Wind tunnel test method and system for quantifying material surface salt deposition flux

Abstract

The invention relates to the technical field of wind tunnel tests, solves the technical problem that the deposition flux of salt on the surface of a material cannot be accurately quantified in a wind tunnel test environment in the prior art, and provides a wind tunnel test method for quantifying the deposition flux of salt on the surface of the material. The method comprises the following steps: evaluating the salt mist spatial distribution uniformity in a wind tunnel salt mist test environment, and obtaining a target wind tunnel salt mist test environment meeting a preset salt mist spatial distribution condition; dynamically adjusting the spraying rate in the target wind tunnel salt spray test environment according to a preset target salt spray concentration value, and obtaining sedimentation liquid samples corresponding to preset sedimentation liquid collection positions in the target wind tunnel salt spray test environment; and carrying out sample analysis and parameter quantification on the sedimentation liquid sample to obtain key parameters for quantifying the deposition flux of the salt on the surface of the material. The method can accurately quantify the salt deposition flux on the surface of the material in a wind tunnel test environment.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing technology, and in particular to a wind tunnel testing method and system for quantifying the salt deposition flux on the surface of materials. Background Technology

[0002] Salt spray corrosion is a crucial factor affecting the service performance of materials and structures in marine, coastal atmospheric, and high-humidity, high-salt environments. To assess the durability and reliability of materials in salt spray environments, accelerated testing is typically used to simulate the salt input conditions experienced by materials in real-world environments, and to quantitatively analyze the salt received by the material surface. Compared to traditional static salt spray test chambers, wind tunnel testing can simultaneously introduce environmental factors such as airflow, temperature, and humidity under controlled conditions, more closely resembling real-world service conditions. Therefore, it has gradually become an important technical means for research on salt spray corrosion and environmental simulation testing of materials. However, quantitatively obtaining the salt deposition flux on the material surface under dynamic airflow conditions in a wind tunnel faces significant technical challenges. On the one hand, the trajectory of salt spray droplets under airflow is complex and variable. The open-type sedimentation collection method commonly used in traditional static salt spray tests is easily affected by lateral airflow in a wind tunnel environment, resulting in low collection efficiency and difficulty in accurately reflecting the actual salt input received by the material surface. Consequently, the test results are difficult to quantify and have poor repeatability. On the other hand, in order to simulate the real atmospheric environment, especially the low-concentration salt spray environment that is common in coastal areas, it is necessary to form and maintain a stable, controllable and spatially uniform salt spray concentration field in the wind tunnel test section for a long time, which is particularly difficult under dynamic airflow conditions.

[0003] To address the aforementioned issues, existing technologies have attempted to improve the accuracy and automation of salt spray testing from different perspectives. For example, existing patents propose online salinity monitoring devices that dynamically monitor salt spray concentration by comparing sampling results before and after salt spray testing (e.g., CN120629270A). While this technology can reflect changes in salt spray concentration, it is primarily used for performance evaluation of components such as filters, focusing on concentration monitoring itself and not addressing closed-loop regulation of the salt spray process under dynamic airflow conditions in a wind tunnel. This makes it difficult to guarantee the stability of salt spray concentration within the target range during testing. Other technologies have proposed broad-spectrum salt spray artificial simulation systems capable of simulating various salt spray environments, such as high-temperature and acidic conditions (e.g., CN222952174U). These systems offer advantages in terms of salt spray type and operating condition coverage, but their salt spray generation process typically relies on open-loop liquid supply or preset spray parameters, making it difficult to adjust the spray rate in real-time according to changes in airflow conditions within the wind tunnel. Therefore, maintaining a stable and spatially uniform salt spray environment in dynamic wind fields remains challenging. Furthermore, for monitoring salt spray deposition behavior, existing technologies have achieved automated measurement of salt spray deposition rates using impedance methods (e.g., CN115493981B). These methods are suitable for continuous monitoring in static or low-flow-rate environments. However, under high-speed airflow conditions such as wind tunnels, salt spray droplets are significantly affected by aerodynamic effects, making it difficult for these methods to achieve isodynamic sampling. Consequently, the measurement results cannot accurately reflect the actual salt deposition on the material surface in a dynamic wind field. Some technologies also improve the spraying and humidification processes in salt spray test chambers by optimizing the spray structure or liquid level control methods to enhance spray uniformity and control accuracy (e.g., CN223166557U, CN223276461U). However, these technologies still limit the control object to the spraying process inside the static test chamber, failing to address the assessment of the spatial distribution uniformity of salt spray under dynamic airflow conditions in wind tunnels, and even more so, failing to establish a control mechanism for dynamically adjusting the spray rate based on the spatial distribution assessment results.

[0004] Therefore, how to accurately quantify the salt deposition flux on the material surface in a wind tunnel testing environment is a technical problem that urgently needs to be solved. Summary of the Invention

[0005] In view of this, embodiments of the present invention provide a wind tunnel testing method and system for quantifying the salt deposition flux on the surface of materials, in order to solve the problem in the prior art that the salt deposition flux on the surface of materials cannot be accurately quantified in a wind tunnel testing environment.

[0006] In a first aspect, embodiments of the present invention provide a wind tunnel testing method for quantifying the salt deposition flux on a material surface, the method comprising: The uniformity of salt spray spatial distribution in the wind tunnel salt spray test environment is evaluated to obtain a target wind tunnel salt spray test environment that meets the preset salt spray spatial distribution conditions; Based on the preset target salt spray concentration value, the spray rate in the target wind tunnel salt spray test environment is dynamically adjusted, and sediment samples corresponding to each preset sediment collection location in the target wind tunnel salt spray test environment are obtained. The sedimentation fluid sample was analyzed and its parameters were quantified to obtain key parameters for quantifying the salt deposition flux on the material surface.

[0007] In an optional embodiment, evaluating the spatial distribution uniformity of salt spray within the wind tunnel salt spray testing environment to obtain a target wind tunnel salt spray testing environment that meets preset salt spray spatial distribution conditions includes: According to the preset grid layout method, the collection locations of each sediment in the wind tunnel salt spray test environment are obtained; Based on the preset target salt spray conditions, the operating parameters of the wind tunnel salt spray test environment are adjusted to obtain the initial wind tunnel salt spray test environment; The sedimentation rate at each sedimentation collection location within the initial wind tunnel salt spray test environment is obtained by collecting and calculating the sedimentation fluid at each sedimentation collection location. The uniformity of the spatial distribution of the salt spray is evaluated based on the settling rate corresponding to each settling liquid collection location, and the evaluation results are obtained. If the evaluation result indicates that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions, then the wind tunnel salt spray test environment is adjusted, and the adjusted wind tunnel salt spray test environment is used as a new wind tunnel salt spray test environment. The process of adjusting the operating parameters of the wind tunnel salt spray test environment according to the preset target salt spray conditions is repeated until the evaluation result indicates that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions. If the evaluation result indicates that the uniformity of the salt spray spatial distribution meets the preset salt spray spatial distribution conditions, then the current wind tunnel salt spray test environment will be used as the target wind tunnel salt spray test environment.

[0008] In an optional embodiment, the evaluation of the spatial distribution uniformity of the salt spray based on the settling rate corresponding to each of the settling liquid collection locations, and the resulting evaluation, includes: Based on the settlement rates described, the average and standard deviation of the settlement rates were calculated. The coefficient of variation for each of the settlement rates is calculated based on the average value and standard deviation. The coefficient of variation is compared with a preset coefficient of variation threshold. If the coefficient of variation is less than or equal to the coefficient of variation threshold, the evaluation result is that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions. If the coefficient of variation is greater than the coefficient of variation threshold, the evaluation result is that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions.

[0009] In an optional embodiment, the step of dynamically adjusting the spray rate within the target wind tunnel salt spray test environment according to a preset target salt spray concentration value, and obtaining sediment samples corresponding to each preset sediment collection location within the target wind tunnel salt spray test environment, includes: The salt spray concentration in the target wind tunnel salt spray test environment is collected to obtain the real-time salt spray concentration value; The difference between the real-time salt spray concentration value and the target salt spray concentration value is calculated to obtain the salt spray concentration difference. Based on the salt spray concentration difference, the spray rate is dynamically adjusted using a PID algorithm to maintain a stable salt spray concentration in the target wind tunnel salt spray test environment. In response to a sediment collection signal, a sediment sample is acquired within the target wind tunnel salt spray test environment where the salt spray concentration is stable.

[0010] In an optional embodiment, the step of dynamically adjusting the spray rate using a PID algorithm based on the salt spray concentration difference to maintain a stable salt spray concentration in the target wind tunnel salt spray test environment includes: Based on the salt spray concentration difference, the spray rate adjustment amount is calculated using the PID algorithm. The spray rate is adjusted according to the spray rate adjustment amount to obtain the adjusted spray rate; Based on the adjusted spray rate, the salt spray concentration in the target wind tunnel salt spray test environment is collected again to obtain a new real-time salt spray concentration value. The new real-time salt spray concentration value is compared with the target salt spray concentration value to obtain a new salt spray concentration difference value; Based on the new salt spray concentration difference, determine whether the new salt spray concentration difference meets the preset concentration stability condition; If the new salt spray concentration difference satisfies the concentration stability condition, then the current spray rate is maintained; If the new salt spray concentration difference does not meet the concentration stability condition, then return to the step of calculating the spray rate adjustment amount using the PID algorithm based on the salt spray concentration difference, until the new salt spray concentration difference meets the concentration stability condition.

[0011] In an optional embodiment, the step of performing sample analysis and parameter quantification on the sediment sample to obtain key parameters for quantifying the salt deposition flux on the material surface includes: The volume or mass of the sediment sample is measured to obtain sediment volume parameters or sediment mass parameters; The concentration of the sediment sample was analyzed by conductivity method to obtain the sediment concentration parameters at each preset sediment collection location; Based on the sediment volume parameter or sediment mass parameter, and combined with the sediment concentration parameter, the salt spray sedimentation amount parameter is calculated. Based on the salt spray deposition parameters, the salt spray deposition rate at each preset deposition liquid collection location is calculated to obtain the target salt spray deposition rate. The average salt spray settling rate and the average settling liquid concentration of each of the target salt spray settling rates are calculated to obtain the average salt spray settling rate and the average settling liquid concentration. The key parameters are determined based on the average salt spray settling rate and the average settling liquid concentration.

[0012] In an optional embodiment, the step of calculating the salt spray settling rate at each preset settling liquid collection location based on the salt spray settling amount parameter to obtain each target salt spray settling rate includes: Obtain the salt spray deposition parameters and test condition parameters corresponding to each preset sedimentation collection location, wherein the test condition parameters include the sampling duration and the effective sampling area; Based on the salt spray deposition parameters and test condition parameters, the target salt spray deposition rates are calculated.

[0013] In a second aspect, embodiments of the present invention provide a wind tunnel testing system for quantifying the salt deposition flux on a material surface, used to implement the wind tunnel testing method for quantifying the salt deposition flux on a material surface as described in the first aspect, the system comprising: The wind tunnel environment simulation module is used to provide a test section and simulate and adjust the wind speed and environmental parameters within the test section; A salt spray generating module is used to atomize the salt solution and supply salt spray to the test section; The parameter acquisition module includes a salt spray concentration monitoring device set in the test section and multiple salt spray sedimentation collection devices arranged in the sample area, used to acquire salt spray concentration data and collect sedimentation samples. The central control module is connected to the wind tunnel environment simulation module, the salt spray generation module, and the parameter acquisition module. It is used to perform closed-loop control of the salt spray generation module based on the salt spray concentration data and to record the data corresponding to the sedimentation sample to support the quantification of salt deposition flux.

[0014] In an optional embodiment, the salt spray sedimentation collection device has an air inlet and a collection container. The air inlet is provided with a windproof and flow-guiding structure and is configured such that the deviation between the air inlet direction and the dominant airflow direction of the test section is no greater than a preset angle, so as to be suitable for collecting sediment samples in a dynamic wind field.

[0015] In an optional embodiment, the central control module is configured to adjust the atomization output of the salt spray generation module based on the deviation between the salt spray concentration data output by the salt spray concentration monitoring device and a preset target value, so as to maintain the stability of the salt spray concentration in the test section.

[0016] In summary, the beneficial effects of the present invention are as follows: This invention provides a wind tunnel testing method and system for quantifying the salt deposition flux on material surfaces. The method includes: evaluating the spatial distribution uniformity of salt spray in a wind tunnel salt spray testing environment to obtain a target wind tunnel salt spray testing environment that meets preset salt spray spatial distribution conditions; dynamically adjusting the spray rate in the target wind tunnel salt spray testing environment according to a preset target salt spray concentration value, and obtaining sediment samples corresponding to preset sediment collection locations in the target wind tunnel salt spray testing environment; and performing sample analysis and parameter quantification on the sediment samples to obtain key parameters for quantifying the salt deposition flux on material surfaces. This invention decomposes the quantification process of salt deposition flux into three closed-loop links: establishing environmental controllability, stabilizing the input process, and calculating the output parameters. This transforms the originally unknown surface salt reception in the dynamic airflow of the wind tunnel into repeatable and traceable quantitative results. First, the uniformity of salt spray spatial distribution within the wind tunnel salt spray testing environment is evaluated and a target wind tunnel salt spray testing environment that meets the preset spatial distribution conditions is selected. This ensures that the sample area is in a spatially consistent salt spray field, reducing sampling bias and result dispersion caused by spatial inhomogeneity. Second, within this target wind tunnel salt spray testing environment, the spray rate is dynamically adjusted based on a preset target salt spray concentration value to maintain a stable salt spray input intensity over time. This suppresses concentration fluctuations and long-term drift caused by wind field disturbances at the source, making the salt spray environment input a controllable quantity. Simultaneously, sediment samples are acquired at each preset sediment collection location under controlled conditions. This converts the surface salt reception process, which is difficult to measure directly in a dynamic wind field, into analyzable sediment sample data. Finally, through sample analysis and parameter quantification, such as volume or mass measurement and concentration analysis of the sediment samples, key parameters characterizing the salt deposition level in the sample area are calculated. This allows for the use of measurable sediment results to infer and quantify the salt deposition flux on the material surface. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the embodiments of the present invention will be briefly introduced below. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort, and these are all within the protection scope of the present invention.

[0018] Figure 1 This is a schematic diagram of the overall process of the wind tunnel test method for quantifying the salt deposition flux on the surface of materials in Embodiment 1 of the present invention; Figure 2 This is a schematic diagram of the salt spray settling and collection device arrangement in the wind tunnel test section of Embodiment 1 of the present invention; Figure 3 This is a schematic diagram of the process of performing sample analysis and parameter quantification on the sediment sample in Embodiment 1 of the present invention to obtain key parameters for quantifying the salt deposition flux on the material surface. Figure 4 This is a schematic diagram of the sedimentation collection device with a windproof and flow-guiding structure in Embodiment 2 of the present invention; The numbers in the diagram are as follows: 1-Windproof deflector; 2-Liquid storage tank; 3-Settling liquid; 4-Drainage rod; 5-Dominant wind direction. Detailed Implementation

[0019] The features and exemplary embodiments of various aspects of the present invention will now be described in detail. To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present invention and are not configured to limit the present invention. For those skilled in the art, the present invention can be practiced without some of these specific details. The following description of the embodiments is merely intended to provide a better understanding of the present invention by illustrating examples of the invention.

[0020] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising..." does not exclude the presence of additional identical elements in the process, method, article, or apparatus that includes said element.

[0021] It should be noted that all actions involving the acquisition of signals, information, or data in this invention are carried out in compliance with the relevant data protection laws and regulations of the locality and with authorization from the owner of the relevant device.

[0022] Example 1 Please see Figure 1 This invention provides a wind tunnel testing method for quantifying the salt deposition flux on a material surface, the method comprising: The uniformity of salt spray spatial distribution in the wind tunnel salt spray test environment is evaluated to obtain a target wind tunnel salt spray test environment that meets the preset salt spray spatial distribution conditions; Specifically, the uniformity of salt spray spatial distribution reflects whether the salt spray deposition levels at different locations within the test section are of the same order of magnitude, avoiding different salt spray inputs to the sample area due to different locations. In engineering, multiple sampling points can be arranged in a grid pattern within the test section, typically with no fewer than nine deposition collection devices as spatial sampling points. After the system reaches the target salt spray conditions, deposition data at each point is acquired, and the coefficient of variation (CV) of the deposition rate is calculated as a uniformity index. If the CV meets the threshold, the preset salt spray spatial distribution conditions are considered met, forming a target wind tunnel salt spray test environment suitable for subsequent quantitative experiments. If the CV does not meet the threshold, adjustments can be made to the nozzle layout or airflow organization until the requirements are met, ensuring that differences in subsequent sampling results are more due to controlled conditions than system deviations caused by spatial inconsistencies. Based on the preset target salt spray concentration value, the spray rate within the target wind tunnel salt spray test environment is dynamically adjusted, and deposition samples corresponding to each preset deposition collection location within the target wind tunnel salt spray test environment are acquired. Specifically, the target salt spray concentration value is used to define the set level of salt spray mass concentration within the test section, and the spray rate corresponds to the intensity of the salt spray output by the atomizer to the test section. Together, they determine the controllability of the salt spray environment input. During the salt spraying phase, the system outputs the concentration monitoring value in real time from the online salt spray concentration monitoring probe. The central control system compares the monitoring value with the target value and runs a PID algorithm to continuously adjust the atomizer spray rate to resist concentration fluctuations caused by changes in wind tunnel airflow. At the same time, it sends a synchronous trigger signal to each sedimentation collection device, so that the preset sedimentation liquid collection positions start and stop collecting synchronously within the same exposure window, obtaining sedimentation liquid samples corresponding to the salt spray input at that stage, avoiding the decrease in sample comparability caused by inconsistent collection times.

[0023] The sedimentation fluid sample was analyzed and its parameters were quantified to obtain key parameters for quantifying the salt deposition flux on the material surface.

[0024] Specifically, the sedimentation sample is a liquid sample collected at each sampling point during the salt spraying stage. It can be regarded as a measurable carrier for the reception of salt near the sample. The sample analysis usually includes volume or mass measurement of each sedimentation sample, and concentration analysis is performed using the conductivity method to obtain the sedimentation concentration parameter. Based on this, the salt spray sedimentation rate at each sampling point is calculated according to the sedimentation data. Then, the average value of the salt spray sedimentation rate and sedimentation concentration parameter at each sampling point is calculated to form the statistically representative average salt spray sedimentation rate and average sedimentation concentration of the sample area. Both serve as key parameters for quantifying the salt deposition flux on the material surface, transforming the surface salt input, which was originally difficult to measure directly under the dynamic airflow conditions of the wind tunnel, into a verifiable and repeatable quantitative result.

[0025] In an optional embodiment, evaluating the spatial distribution uniformity of salt spray within the wind tunnel salt spray testing environment to obtain a target wind tunnel salt spray testing environment that meets preset salt spray spatial distribution conditions includes: According to the preset grid layout method, the collection locations of each sediment in the wind tunnel salt spray test environment are obtained; Specifically, the grid layout method refers to dividing the wind tunnel test section into several grid cells according to rules, and selecting sedimentation collection points at the intersections of each grid or within representative cells. This is used to characterize the spatial distribution of the salt spray field. The sedimentation collection points can be understood as the locations of the collection devices, for example, evenly distributing points along the upstream, middle, and downstream sides of the sample area, as well as at different lateral positions, forming a sampling array covering the perimeter of the sample. Pre-determining the collection points ensures spatial comparability of subsequent data collection, avoiding distortion of uniformity judgments due to sampling only at local locations. The grid layout also facilitates subsequent statistical analysis of the sedimentation rates at each point and calculation of the dispersion, reflecting whether the spatial distribution of the salt spray meets the preset requirements. Please refer to [link to relevant documentation]. Figure 2 , Figure 2This is a top-down view of the salt spray deposition collection device within the wind tunnel test section. The test section is rectangular in shape, with an outer boundary dimension of 3000mm × 3000mm. The effective test area is 2500mm × 2500mm, and the sample is positioned at the center of the test section. Multiple concentric rings of deposition collection points are arranged outwards from the sample, with each sampling point evenly distributed circumferentially to form a regular ring sampling array. The sample area is located in the center of the test section, with multiple concentric rings of deposition collection points arranged outwards from the sample, forming a regular ring sampling array. The radii of each ring, from the center outwards, are 600mm, 900mm, and 1250mm, respectively. Different ring radii correspond to different distance levels, used to characterize the deposition distribution of salt spray in the space surrounding the sample. Multiple sampling points together constitute a spatial sampling grid covering the sample area. The test section is surrounded by wind tunnel wall structures. The airflow flows through the sample area along the dominant direction of the test section and passes through the locations of each sediment collection device. This arrangement can simultaneously acquire sedimentation data from multiple points without significantly disturbing the mainstream airflow, providing a spatial basis for assessing the spatial uniformity of salt spray distribution and for subsequent statistical calculations of average sedimentation rate and average sediment concentration.

[0026] Based on the preset target salt spray conditions, the operating parameters of the wind tunnel salt spray test environment are adjusted to obtain the initial wind tunnel salt spray test environment; Specifically, the target salt spray condition defines the desired salt spray environment state during this uniformity commissioning. The operating parameters correspond to the controllable quantities of the wind tunnel and salt spray generation system, which together determine the wind speed, temperature, humidity, and salt spray concentration levels within the test section. Operating parameter adjustments are typically based on the settings of the wind tunnel environment simulation body, while simultaneously ensuring stable output of salt spray generation and delivery. This allows the test section to enter a sampleable initial wind tunnel salt spray test environment. The initial state does not require immediate uniformity; it only needs to reach the basic operating point corresponding to the target salt spray condition. This facilitates subsequent evaluation of spatial distribution differences using sedimentation data from each sampling point and provides a basis for determining whether further adjustments to the nozzle layout or airflow organization are necessary.

[0027] The sedimentation rate at each sedimentation collection location within the initial wind tunnel salt spray test environment is obtained by collecting and calculating the sedimentation fluid at each sedimentation collection location. Specifically, sedimentation collection refers to the collection and aggregation of sedimentation samples by various collection devices within the same salt spray exposure window. Sedimentation rate characterizes the amount of salt spray sedimentation obtained per unit time at the corresponding collection location, serving as fundamental data for subsequent uniformity assessment. During collection, each collection device operates synchronously during a controlled salt spraying phase. After the phase concludes, sedimentation samples are collected uniformly. In the laboratory, the volume or mass of each sample is measured, and concentration parameters obtained through conductivity analysis are used to calculate the sedimentation amount at that point. This sedimentation rate is then calculated by combining the collection duration with the sedimentation rate data. This ensures that each collection location corresponds to a set of sedimentation rate data suitable for spatial comparison, providing a quantitative basis for subsequent calculations of dispersion based on multi-point data and for determining the uniformity of the salt spray field.

[0028] The uniformity of the spatial distribution of the salt spray is evaluated based on the settling rate corresponding to each settling liquid collection location, and the evaluation results are obtained. Specifically, sedimentation rate is a quantitative indicator reflecting the actual deposition level of salt spray at different spatial locations. Using the sedimentation rate corresponding to each sediment collection location as input, the spatial distribution of salt spray within the test section can be reflected as a whole. During evaluation, statistical processing can be performed on the sedimentation rates at multiple points, such as calculating the mean and dispersion. Indicators like the coefficient of variation characterize the relative differences between locations; the smaller the dispersion, the more consistent the spatial distribution of salt spray. This evaluation result is not simply a judgment of whether a single sampling point meets the standard, but rather a comprehensive assessment of the salt spray distribution characteristics of the entire sample area based on multi-point data. This allows for quantitative comparison and judgment of the spatial state of salt spray, providing a basis for determining whether adjustments to the test environment are necessary.

[0029] In one embodiment, the evaluation of the spatial distribution uniformity of the salt spray based on the settling rate corresponding to each of the settling liquid collection locations, and the resulting evaluation, includes: Obtain the settling rate corresponding to each of the settling liquid collection locations, and summarize the settling rates to form a set of settling rates; Specifically, sedimentation rate is a quantitative result used to characterize the amount of salt spray deposited per unit time and unit area at each sedimentation collection location. It is usually calculated by combining the salt spray sedimentation parameter at that location with the sampling duration and the effective sampling area. Therefore, when forming a sedimentation rate set, it is necessary to first extract the sedimentation rate corresponding to each sedimentation collection location one by one, and verify whether these sedimentation rates come from the sampling window under the same round of target salt spray conditions, to avoid mixing calculation results from different sampling durations or different effective sampling areas into the same set. In implementation, the central control system can generate a record for each sedimentation collection location after sampling. The record includes the location number, sampling duration, effective sampling area, salt spray sedimentation parameter, and the calculated sedimentation rate. Then, the sedimentation rates of all locations are summarized into a sedimentation rate set in a preset order. Subsequent evaluations are only performed on this set. This ensures that the data caliber for the evaluation of the uniformity of salt spray spatial distribution is consistent and avoids distortion of evaluation results due to inconsistent data sources.

[0030] Based on the set of settlement rates, the average and standard deviation of the settlement rates are calculated, and the coefficient of variation is calculated based on the average and standard deviation. Specifically, the average value reflects the central level of the overall settling intensity under the current wind tunnel salt spray test environment, while the standard deviation reflects the dispersion of settling rates between different settling fluid collection locations. The coefficient of variation, obtained by combining the two, normalizes the dispersion to an average level, facilitating horizontal comparisons between different target salt spray concentrations or different test batches. During calculation, statistical operations can be directly performed on the set of settling rates. First, the settling rates within the set are summed and divided by the number of locations to obtain the average settling rate. Then, the standard deviation is calculated based on the deviation of each settling rate from the average value. Finally, the coefficient of variation is obtained by the ratio of the standard deviation to the average value. When the average value is close to zero, causing instability in the ratio, a minimum average value constraint can be set under the same calculation rules, or equivalent normalization processing can be used to ensure the engineering usability of the coefficient of variation determination. By placing the primary criterion for uniformity on the coefficient of variation, a quantitative indicator can intuitively reflect whether there is overall inhomogeneity in the salt spray field, thus providing a clear basis for subsequent parameter adjustment and reducing interference from single-point anomalies or random fluctuations in the determination.

[0031] Based on the set of settlement rates, determine the maximum and minimum settlement rates, and calculate the ratio of the maximum to the minimum values; Specifically, the maximum and minimum values ​​reflect the locations of strongest and weakest settlement in the set of settlement rates, respectively. The ratio of the maximum to the minimum value characterizes the extreme differences between the worst-case locations, compensating for the insensitivity of the coefficient of variation to local extreme points. In implementation, each settlement rate in the set of settlement rates is traversed, and the current maximum and minimum values ​​are updated accordingly. After obtaining the final maximum and minimum values, their ratio is calculated. To avoid an abnormally amplified ratio due to an excessively small minimum value, a reasonable lower limit can be set for the minimum value without changing the calculation logic, or a validity check consistent with the sampling duration and effective sampling area can be used to ensure that the minimum value indeed comes from valid sampling. Introducing the ratio of the maximum and minimum values ​​allows for timely identification of locations with significantly higher or lower values, even if the overall dispersion is not large. This helps to discover potential local flow deviations, local enrichment, or local dilution in the wind tunnel salt spray testing environment, thereby improving the sensitivity of salt spray spatial distribution uniformity assessment to abnormal areas.

[0032] The sediment collection locations are grouped into a central region group and an edge region group. The average sedimentation rate of the central region and the average sedimentation rate of the edge region are calculated respectively, and then the difference value between the central region and the edge region is calculated. Specifically, when dividing the sediment collection locations into central region groups and edge region groups, the central region and edge region correspond to different spatial areas on the cross-section of the test section or the target evaluation plane in the wind tunnel salt spray test environment. The purpose of grouping is to identify whether there is a systematic deviation in the salt spray between the core region and the boundary region. In practice, the spatial coordinates or grid number of each sediment collection location can be determined first according to a preset grid layout method, and then the classification can be completed according to preset grouping rules. For example, several points at the center of the grid can be defined as the central region group, and points near the wall or the boundary can be defined as the edge region group. The grouping rules should be kept consistent for each test for comparison. After grouping, the average settling rate of the central region is obtained by averaging the settling rate of the central region group and the average settling rate of the peripheral region group. Finally, the difference or relative difference between the two is used to form the difference value between the central region and the peripheral region. This difference value can directly reflect whether there is a trend of central enrichment or peripheral enrichment in the spatial distribution of salt spray. It helps to find regional non-uniformity caused by airflow boundary layer, wall effect or backflow organization even when the overall coefficient of variation is not high, so that the uniformity assessment is closer to the actual wind tunnel operation characteristics.

[0033] Obtain adjacent sedimentation liquid collection location pairs, calculate the sedimentation rate difference of each adjacent sedimentation liquid collection location pair, and calculate the spatial gradient change rate based on the sedimentation rate difference. Specifically, adjacent sedimentation collection location pairs correspond to two spatially adjacent sampling points under the grid layout method. The spatial gradient change rate is used to characterize the degree of abrupt change in sedimentation rate in space, revealing gradient anomalies caused by local inhomogeneities or local flow deviations. In implementation, adjacent sedimentation collection location pairs can first be generated based on the adjacency relationship of the grid layout method, for example, by row and column adjacency or by obtaining a list of adjacent point pairs according to preset neighborhood rules. Then, the sedimentation rate of each pair of adjacent sedimentation collection locations is read and the sedimentation rate difference is calculated. When spatial scale needs to be represented, the sedimentation rate difference can be further correlated with the grid spacing between the two points, so that the gradient representation has a consistent spatial benchmark. Subsequently, the sedimentation rate differences of all adjacent sedimentation collection location pairs can be summarized, and the spatial gradient change rate can be calculated according to a preset method, such as taking the average, maximum, or root mean square value of the difference as the spatial gradient change rate to reflect the smoothness of the sedimentation rate in space. By introducing the spatial gradient rate of change, even if the central and peripheral regions are generally similar, it is possible to identify situations where there are sharp changes in local areas. This improves the ability of uniformity assessment to detect local anomalies and avoids missed detections caused by relying solely on overall statistics.

[0034] The coefficient of variation is compared with a preset coefficient of variation threshold to obtain the main evaluation result, and the ratio of the maximum value to the minimum value, the difference between the central region and the edge region, and the spatial gradient change rate are compared with the corresponding auxiliary thresholds to obtain the auxiliary evaluation result. Specifically, the main evaluation result is based on the comparison of the coefficient of variation with the coefficient of variation threshold, ensuring that the uniformity assessment still uses the overall dispersion as the core criterion. The auxiliary evaluation results supplement the identification of extreme differences, regional deviations, and local abrupt changes by comparing the ratio of maximum to minimum values, the difference between the central and peripheral regions, and the spatial gradient change rate with their respective auxiliary thresholds. In implementation, the coefficient of variation is first calculated and compared with the coefficient of variation threshold to obtain the main evaluation result as either meeting or not meeting the preset salt spray spatial distribution conditions. Then, the ratio of maximum to minimum values, the difference between the central and peripheral regions, and the spatial gradient change rate are compared item by item with the corresponding auxiliary thresholds to obtain the judgment set for whether each auxiliary indicator meets the standard, thus forming the auxiliary evaluation result. This multi-indicator comparison method maps different types of non-uniformity phenomena to quantifiable criteria, ensuring that the evaluation result retains the judgment of overall consistency while also covering the risk points of local and regional deviations, avoiding situations where the coefficient of variation meets the standard but there are significant deviations in local or boundary areas.

[0035] The evaluation result is determined based on the main evaluation result and the auxiliary evaluation result.

[0036] Specifically, when determining the evaluation result based on the main evaluation result and the auxiliary evaluation result, a consistency judgment logic can be used to ensure the stability of the conclusion. For example, the main evaluation result can be used as a necessary condition, and the auxiliary evaluation result can be used as a constraint condition to form a uniformity judgment rule that is more in line with engineering applications. In implementation, it can be set that when the main evaluation result meets the preset salt spray spatial distribution conditions and all judgments in the auxiliary evaluation results meet the corresponding auxiliary thresholds, the output evaluation result is that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions; if the main evaluation result does not meet or any auxiliary indicator does not meet the corresponding auxiliary threshold, the output evaluation result is that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions, and the unmet item is used as the basis for subsequent wind tunnel salt spray test environment parameter adjustment. Through this main-auxiliary combined determination method, the evaluation result can more realistically reflect the spatial distribution state of the wind tunnel salt spray test environment, making subsequent parameter adjustment actions more targeted, improving the reliability of the target wind tunnel salt spray test environment selection, and thus improving the repeatability and interpretability of the quantitative results of salt deposition flux on the material surface.

[0037] If the evaluation result indicates that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions, then the wind tunnel salt spray test environment is adjusted, and the adjusted wind tunnel salt spray test environment is used as a new wind tunnel salt spray test environment. The process of adjusting the operating parameters of the wind tunnel salt spray test environment according to the preset target salt spray conditions is repeated until the evaluation result indicates that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions. Specifically, when the evaluation results show that the difference in sedimentation rate between different sampling points exceeds a preset threshold, it indicates that there is still significant spatial inhomogeneity in the current salt spray field. At this time, further adjustments to the wind tunnel salt spray test environment are needed. The adjustment method can be based on the evaluation results to specifically change the wind tunnel operating parameters, nozzle layout, or airflow organization to make the salt spray transport and diffusion process more balanced. The adjusted wind tunnel salt spray test environment is regarded as a new test object, and the process of setting operating parameters, sampling, and calculating sedimentation rate is repeated. Through repeated sampling and evaluation, the spatial distribution state of salt spray is gradually converged, and the environmental state that does not meet the conditions is continuously corrected until the sedimentation rate distribution at multiple points stabilizes within the preset range.

[0038] In an optional embodiment, the step of adjusting the wind tunnel salt spray test environment if the evaluation result indicates that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions, and returning the adjusted wind tunnel salt spray test environment as a new wind tunnel salt spray test environment to the initial wind tunnel salt spray test environment by adjusting the operating parameters of the wind tunnel salt spray test environment according to the preset target salt spray conditions, until the evaluation result indicates that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions, includes: Obtain the coefficient of variation corresponding to the current wind tunnel salt spray test environment, and compare the coefficient of variation with a preset first coefficient of variation threshold and a second coefficient of variation threshold, wherein the first coefficient of variation threshold is greater than the second coefficient of variation threshold. Specifically, the coefficient of variation is used here to characterize the dispersion of sedimentation rates at different sedimentation locations within the current wind tunnel salt spray testing environment. It is a statistical measure of uniformity using a relative scale, facilitating comparability under different target salt spray conditions or different sampling durations. In actual acquisition, after the wind tunnel salt spray testing environment is run according to the preset target salt spray conditions, sedimentation samples are simultaneously acquired at each sedimentation location. Volume or mass measurements are performed on each sedimentation sample, and concentration analysis using conductivity methods is combined to obtain salt spray sedimentation parameters. Then, the sedimentation rate is calculated based on the sampling duration and effective sampling area. Subsequently, the average and standard deviation are calculated based on each sedimentation rate, and the coefficient of variation is obtained accordingly. When comparing the coefficient of variation with the first and second coefficient of variation thresholds, the first coefficient of variation threshold is used to determine the state where the uniformity of salt spray spatial distribution is significantly deviated, and the second coefficient of variation threshold is used to determine the state where the preset salt spray spatial distribution conditions are nearly met but further convergence is still needed. The two form a graded judgment boundary, which provides a clear basis for switching in the subsequent parameter adjustment stage, thereby reducing the number of parameter adjustments caused by repeated trial and error based on experience, and improving the repeatability and traceability of salt spray spatial distribution uniformity debugging.

[0039] When the coefficient of variation is greater than or equal to the first coefficient of variation threshold, the current parameter tuning stage is determined as the coarse tuning stage, and the preset coarse tuning step size is obtained. Specifically, when the coefficient of variation is greater than or equal to the first coefficient of variation threshold, the current parameter tuning stage is defined as the coarse tuning stage, and the coarse tuning step size is obtained. The coarse tuning step size can be understood as the adjustment range of at least one operating parameter in a single operation. Its purpose is to significantly move the current wind tunnel salt spray test environment towards meeting the preset salt spray spatial distribution conditions within a few rounds. The coarse tuning step size can be obtained by the central control system from the step size library based on preset rules. For example, it can be mapped to the corresponding step size level according to the excess range of the coefficient of variation relative to the first coefficient of variation threshold, or upper and lower limits of the coarse tuning step size can be set for different operating parameters to avoid overshoot. At the same time, the coarse tuning step size can be bound to the allowable range of the operating parameters to ensure that subsequent coarse adjustments to the operating parameters will not cause the wind tunnel salt spray test environment to deviate from the achievable operating conditions. By triggering the coarse tuning stage with the first coefficient of variation threshold and matching it with the coarse tuning step size, stronger adjustment actions can be prioritized when the uniformity of the salt spray spatial distribution is significantly insufficient, avoiding repeated sampling and calculation with too small an adjustment range, which would lead to an excessively long debugging cycle.

[0040] Based on the coarse adjustment step size, at least one operating parameter of the wind tunnel salt spray test environment is coarsely adjusted to obtain the coarsely adjusted wind tunnel salt spray test environment; Specifically, when performing coarse adjustments to at least one operating parameter of the wind tunnel salt spray test environment based on the coarse adjustment step size, the central control system can discretely update the setpoint of the selected operating parameter once or multiple times according to the coarse adjustment step size. After each update, the wind tunnel salt spray test environment is brought back into a stable operating window under the target salt spray conditions to ensure that the coarsely adjusted wind tunnel salt spray test environment can truly reflect the adjustment effect. The coarse adjustment of the operating parameters can be performed by adjusting one operating parameter first and observing the trend of the coefficient of variation, or by adjusting two or more operating parameters simultaneously according to a preset ratio using a multi-parameter linkage method. However, each adjustment retains the corresponding parameter records, and the sampling duration and effective sampling area are consistent to facilitate subsequent horizontal comparison based on the sedimentation rate calculated from the sedimentation liquid sample. After the wind tunnel salt spray test environment is formed after coarse adjustment, the transport and mixing state of salt spray in the test section will undergo considerable changes, which will allow the dispersion of sedimentation rate at each sedimentation liquid collection location to converge quickly. This will create a foundation for entering the fine adjustment stage or directly meeting the preset salt spray spatial distribution conditions, while also reducing the risk of deviation in the quantitative distribution of salt deposition flux on the material surface due to uneven spatial distribution of salt spray.

[0041] When the coefficient of variation is less than the first coefficient of variation threshold and greater than the second coefficient of variation threshold, the current parameter tuning stage is determined as the fine-tuning stage, and the preset fine-tuning step size is obtained. Specifically, when the coefficient of variation is already less than the first threshold but still greater than the second threshold, defining the current parameter adjustment stage as the fine-tuning stage is more in line with the rhythm of on-site debugging. At this point, the uniformity of the salt spray spatial distribution has moved from significant unevenness to a convergent range. Continuing to use coarse adjustments can easily cause overshoot or oscillations around the threshold. The fine-tuning step size corresponds to a smaller single adjustment amplitude, which can be directly read by the central control system according to preset rules. For example, the corresponding step size level can be selected based on the difference between the coefficient of variation and the second threshold, or fine-tuning step sizes can be set separately for different operating parameters to match their adjustment sensitivity, avoiding large drifts in the salt spray field caused by small changes in a certain operating parameter. By binding the fine-tuning stage with the fine-tuning step size, subsequent adjustments can be made more refined, making it easier to stably reduce the coefficient of variation to below the second threshold and reduce time consumption and conditional drift caused by repeated experiments.

[0042] Based on the fine-tuning step size, at least one operating parameter of the wind tunnel salt spray test environment is fine-tuned to obtain the fine-tuned wind tunnel salt spray test environment; Specifically, when fine-tuning at least one operating parameter of the wind tunnel salt spray test environment using a fine-tuning step size, the operating parameters are typically updated in small iterative steps, with sufficient stabilization time for the salt spray field after each update, before proceeding to the sampling and calculation stage to verify the adjustment effect. In terms of execution, the operating parameter with the most direct impact on the coefficient of variation can be prioritized for adjustment. Its setpoint is updated once according to the fine-tuning step size. The central control system records the setpoints before and after the update, the update time, and the wind tunnel operating status. After the update, the wind tunnel salt spray test environment is maintained under the target salt spray conditions until the concentration and flow field reach a new stable range. If the coefficient of variation decreases but remains above the second coefficient of variation threshold, the fine-tuning step size is continued to be added in the same direction. If the coefficient of variation increases in the opposite direction, the adjustment direction is switched according to a preset strategy, or another operating parameter is used for fine-tuning. Through this kind of fine-tuning in small steps, the spatial consistency of the settling rate can be further improved without compromising the overall stability of salt spray concentration control, making the fine-tuned wind tunnel salt spray test environment closer to the target state that meets the preset salt spray spatial distribution conditions.

[0043] Based on the coarsely adjusted wind tunnel salt spray test environment and / or the finely adjusted wind tunnel salt spray test environment, each of the sedimentation liquid samples is collected, and each of the sedimentation rates is calculated. Specifically, when collecting sedimentation samples and calculating sedimentation rates under coarsely and / or finely tuned wind tunnel salt spray testing environments, it is necessary to ensure that the sampling action and the target salt spray conditions are within the same stable range to avoid introducing transient parameters or unstable concentration states into the evaluation results. During collection, the central control system sends synchronous acquisition trigger signals to each sedimentation collection location, ensuring that each location operates within the same sampling duration. After sampling, sedimentation samples are uniformly retrieved, and the volume or mass of each sample is measured. The concentration parameters of the sedimentation are obtained using conductivity analysis. Then, the salt spray sedimentation parameters are calculated by combining the effective sampling area and sampling duration, and the sedimentation rates are converted. During the calculation process, the effective sampling area and sampling duration are kept consistent at each sedimentation collection location to reduce spurious dispersion caused by differences in sampling conditions. The sedimentation rates obtained in this way can accurately reflect the spatial distribution of salt spray deposition under coarsely or finely tuned wind tunnel salt spray testing environments, providing reliable input for subsequent recalculation of the coefficient of variation, and establishing the quantification of salt deposition flux on the material surface on a repeatable sampling and calculation chain.

[0044] The coefficient of variation is recalculated based on each of the settlement rates, and the evaluation results are updated based on the recalculated coefficient of variation. Specifically, when recalculating the coefficient of variation after obtaining each settling rate, the settling rate is still calculated point-by-point according to each settling fluid collection location, and the calculation caliber remains consistent with the previous round. First, the average value of each settling rate is calculated, then the standard deviation is calculated, and finally, the coefficient of variation is obtained to characterize the spatial distribution uniformity of salt spray in the current wind tunnel salt spray test environment. To ensure the repeatability of the updated evaluation results, a consistency check can be performed on the settling rate data before calculation. For example, the sampling duration and effective sampling area can be verified to be consistent with the settings of this round, and there can be no obvious abnormalities such as missed sampling or measurement errors. After confirming that there are no errors, the coefficient of variation is output, and the evaluation results are updated accordingly to indicate whether the spatial distribution uniformity of salt spray meets or does not meet the preset salt spray spatial distribution conditions. This transforms the evaluation results from subjective judgment to quantitative judgment based on settling rate data, ensuring that the environmental state after each parameter adjustment has a clear evaluation basis. This avoids inconsistencies in uniformity judgment caused by transient fluctuations or differences in human experience under dynamic airflow conditions in the wind tunnel, thereby ensuring the stability and reliability of the environmental benchmark upon which the subsequent quantification of salt deposition flux on the material surface relies.

[0045] When the updated evaluation result indicates that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions, the recalculated coefficient of variation is used as the input parameter for the next round of graded parameter tuning. The process returns to the step of obtaining the coefficient of variation corresponding to the current wind tunnel salt spray test environment and comparing the coefficient of variation with the preset first and second coefficient of variation thresholds to redetermine the parameter tuning stage and perform the corresponding coarse or fine adjustment until the updated evaluation result indicates that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions.

[0046] Specifically, when the updated evaluation result still indicates that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions, the recalculated coefficient of variation is used as the input parameter for the next round of graded parameter adjustment and returned to the stage of comparison with the first and second coefficient of variation thresholds. This is to ensure that the parameter adjustment forms a closed-loop iteration rather than a one-time adjustment. In practice, the central control system writes the coefficient of variation of this round into the parameter adjustment record and uses it as the judgment value for the new round. It then compares it again with the first and second coefficient of variation thresholds to determine the next round of parameter adjustment. If the coefficient of variation is still greater than or equal to the first coefficient of variation threshold, it enters the coarse adjustment stage and performs coarse adjustment on at least one operating parameter according to the coarse adjustment step size. If the coefficient of variation falls between the first and second coefficient of variation thresholds, it enters the fine adjustment stage and performs fine adjustment on at least one operating parameter according to the fine adjustment step size. After each round of corresponding operating parameter adjustment is completed, the system runs under the target salt spray conditions and collects sedimentation samples simultaneously to calculate the sedimentation rate. Then, the coefficient of variation is recalculated and the evaluation result is updated. This cycle continues until the evaluation result meets the preset salt spray spatial distribution conditions. By using a graded parameter tuning closed loop driven by the coefficient of variation, it can converge quickly when the deviation is large, and avoid repeated fluctuations caused by over-adjustment when approaching the threshold. This ensures that the uniformity of the salt spray spatial distribution eventually stabilizes to the preset salt spray spatial distribution conditions, thereby improving the controllability of the wind tunnel salt spray test environment and the comparability of the test results.

[0047] If the evaluation result indicates that the uniformity of the salt spray spatial distribution meets the preset salt spray spatial distribution conditions, then the current wind tunnel salt spray test environment will be used as the target wind tunnel salt spray test environment.

[0048] Specifically, when the evaluation results indicate that the dispersion of sedimentation rates at each sedimentation collection location is within a preset threshold, it means that the salt spray in the test section has formed a spatially consistent distribution in the sample area. At this point, the current wind tunnel salt spray test environment is determined as the target wind tunnel salt spray test environment. This environmental condition can serve as the basis for subsequent formal salt spray tests and the quantification of salt deposition flux on material surfaces, ensuring that sedimentation samples obtained under this environment have spatial representativeness and statistical reliability. This reduces systematic errors caused by the inhomogeneity of the salt spray field and provides a stable and repeatable environmental prerequisite for subsequent key parameters obtained based on sample analysis.

[0049] In an optional embodiment, the evaluation of the spatial distribution uniformity of the salt spray based on the settling rate corresponding to each of the settling liquid collection locations, and the resulting evaluation, includes: Based on the settlement rates described, the average and standard deviation of the settlement rates were calculated. Specifically, the average sedimentation rate is used to characterize the central value of salt spray deposition level in the sample area under this grid sampling, and the standard deviation is used to characterize the fluctuation range of sedimentation rate around this central value at each sedimentation collection location. Together, they consolidate the originally discrete multi-point sedimentation rate data into comparable statistics. The average value is mainly calculated based on the arithmetic mean of the sedimentation rates at each sampling point, while the standard deviation is obtained based on the deviation of the sedimentation rate at each point from the average value. It can reflect whether the spatial distribution is concentrated. A smaller standard deviation usually means that the sedimentation levels at each location are more similar, which is beneficial to transform the spatial uniformity of salt spray from empirical judgment to quantitative judgment, and provides the necessary basic parameters for subsequent calculation of the coefficient of variation.

[0050] The coefficient of variation for each of the settlement rates is calculated based on the average value and standard deviation. Specifically, the coefficient of variation is a dimensionless index, used to characterize the relative dispersion by the ratio of the standard deviation to the mean. It allows for comparisons on the same scale under different target salt spray conditions or different settling levels. By combining the standard deviation and the mean to form the coefficient of variation, the uniformity evaluation is no longer affected by the absolute magnitude of the average settling rate. For example, in a low-concentration salt spray environment, the average settling rate is small, and simply looking at the standard deviation can easily exaggerate the degree of fluctuation. Using the coefficient of variation can normalize the fluctuation amplitude to an average level, making the evaluation results more stable, easier to set a uniform threshold, and more suitable for uniformity debugging and repeated verification under different operating conditions in the wind tunnel.

[0051] The coefficient of variation is compared with a preset coefficient of variation threshold. If the coefficient of variation is less than or equal to the coefficient of variation threshold, the evaluation result is that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions. Specifically, the coefficient of variation threshold is a quantitative limit for the allowable deviation of the spatial distribution uniformity of salt spray. It can be preset in conjunction with the grid density and test accuracy requirements. The smaller the threshold, the stricter the requirement for uniformity. A coefficient of variation less than or equal to this threshold means that the relative difference in sedimentation rate between sampling points has been controlled within the allowable range, and the salt spray input in the sample area is spatially consistent. At this time, the evaluation result is judged to meet the preset salt spray spatial distribution conditions, so that when entering the formal salt spray test, no additional compensation is needed for the systematic error introduced by the point difference. The collected sediment samples are more representative of the true receiving level under the same controlled environment.

[0052] If the coefficient of variation is greater than the coefficient of variation threshold, the evaluation result is that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions.

[0053] Specifically, if the coefficient of variation is greater than the threshold, it means that the relative dispersion of the settling rate at each settling fluid collection location exceeds the allowable range, indicating the existence of obvious high and low settling zones in space, and that the salt spray field has not yet reached a uniform state suitable for quantitative testing. In this case, the evaluation result is determined to not meet the preset salt spray spatial distribution conditions. This provides a clear trigger for subsequent adjustments to the wind tunnel salt spray testing environment, creating a closed-loop debugging process. It avoids directly conducting sample analysis when the salt spray field is not yet uniform, which could lead to key parameters deviating from their true levels, thereby improving the repeatability and comparability of subsequent quantitative results.

[0054] In an optional embodiment, the step of dynamically adjusting the spray rate within the target wind tunnel salt spray test environment according to a preset target salt spray concentration value, and obtaining sediment samples corresponding to each preset sediment collection location within the target wind tunnel salt spray test environment, includes: The salt spray concentration in the target wind tunnel salt spray test environment is collected to obtain the real-time salt spray concentration value; Specifically, salt spray concentration refers to the mass concentration of salt spray within the test section. Real-time salt spray concentration values ​​are derived from continuous sampling outputs of the salt spray state within the test section by an online concentration monitoring device. This can be understood as an instantaneous measurement used by the control system to characterize the current salt spray input intensity. The sampling location is typically positioned within the test section to represent the salt spray level of the sample area, ensuring that the collected values ​​reflect the instantaneous fluctuations of the salt spray field within the wind tunnel under dynamic airflow disturbances. After the real-time data enters the central control module, it forms the feedback basis for spray rate adjustment, transforming the salt spray environment from a single-setup state to a continuously observable one. Concentration drift and short-term fluctuations can be captured promptly and used for subsequent calculations.

[0055] The difference between the real-time salt spray concentration value and the target salt spray concentration value is calculated to obtain the salt spray concentration difference. Specifically, the target salt spray concentration is a pre-set concentration benchmark used to define the desired salt spray input level for this experiment. The salt spray concentration difference calculated from the difference represents the direction and magnitude of the deviation between the current salt spray state and the set state. A positive difference indicates that the current concentration is higher than the target, while a negative difference indicates that the current concentration is lower than the target. This deviation signal can be directly used by the control algorithm to determine whether to increase or decrease the spray rate. Differential processing reduces complex environmental disturbances to a single, calculable control variable, enabling the control system to maintain a quantitative adjustment path for the salt spray concentration even under coupled changes in wind speed, humidity, etc., avoiding over-adjustment or under-adjustment caused by relying solely on experience.

[0056] Based on the salt spray concentration difference, the spray rate is dynamically adjusted using a PID algorithm to maintain a stable salt spray concentration in the target wind tunnel salt spray test environment. Specifically, the PID algorithm uses the salt spray concentration difference as input, comprehensively processes the deviation using proportional, integral, and derivative terms, and outputs an adjustment to the spray rate. The spray rate corresponds to the atomization output intensity of the ultrasonic atomizer, and adjusting the spray rate is equivalent to adjusting the supply of salt spray to the test section. The proportional term enables a rapid response when a concentration deviation occurs, the integral term cumulatively corrects persistent deviations to suppress long-term drift, and the derivative term predicts the deviation change trend to reduce oscillations and overshoot, ensuring that the salt spray concentration remains stably within the target range even under dynamic wind field disturbances. Through this closed-loop regulation, the salt spray input intensity is transitioned from an open-loop setting to a stable control state with real-time correction, providing a consistent environmental benchmark for subsequent synchronous collection of sediment samples.

[0057] In response to a sediment collection signal, a sediment sample is acquired within the target wind tunnel salt spray test environment where the salt spray concentration is stable.

[0058] Specifically, the sedimentation collection signal can be issued by the central control module during the salt spraying phase to trigger the synchronous start of collection by each sedimentation collection device. The signal's function is to lock the collection action within a time window when the salt spray concentration is under stable control, ensuring the comparability of samples obtained from each preset sedimentation collection location under the same environmental input conditions. The collection devices are arranged near the sample and start and stop synchronously during the salt spraying phase. After the phase ends, the sedimentation samples are collected uniformly. These samples serve as the basis for subsequent volume or mass measurements and conductivity concentration analysis, converting the surface salt reception process, which is difficult to measure directly in the dynamic airflow of the wind tunnel, into analyzable sample data. The timing coordination between the collection signal and closed-loop control reduces systematic errors caused by sampling window misalignment, making the subsequently calculated salt spray sedimentation rate and average sedimentation concentration more statistically representative.

[0059] In an optional embodiment, the step of dynamically adjusting the spray rate using a PID algorithm based on the salt spray concentration difference to maintain a stable salt spray concentration in the target wind tunnel salt spray test environment includes: Based on the salt spray concentration difference, the spray rate adjustment amount is calculated using the PID algorithm. Specifically, the spray rate adjustment is a correction factor for the atomizer's output intensity, used to bring the salt spray concentration back to the target level from its current deviation. The salt spray concentration difference, as the PID input signal, participates in the calculations of the proportional, integral, and derivative components. The proportional component provides immediate correction based on the current deviation magnitude; the larger the deviation, the more significant the correction. The integral component accumulates the persistent deviation over a period of time, compensating for potential drift during long-term system operation. The derivative component focuses on the deviation trend, suppressing potential overshoot or oscillations to make the adjustment process smoother. This adjustment factor transforms the concentration fluctuations caused by disturbances within the wind tunnel into an executable control output. The atomizer spray can adaptively change according to the magnitude and trend of the deviation, avoiding long-term concentration deviations caused by relying solely on fixed spray parameters.

[0060] The spray rate is adjusted according to the spray rate adjustment amount to obtain the adjusted spray rate; Specifically, the spray rate can be understood as the output intensity of the atomizer atomizing the salt solution and supplying it to the test section. The adjusted spray rate is the control setpoint obtained by superimposing or correcting the original spray rate with the adjusted spray rate. In practice, the central control module can convert the adjusted amount into a control quantity that the atomizer can recognize, such as output power or drive duty cycle, so that the atomization process operates according to the new setpoint, and the supply of salt mist into the test section changes accordingly. Only when the adjustment action is implemented into executable spray control can the deviation of salt mist concentration be effectively eliminated, and the continuously output salt mist input intensity can be corrected according to the changes in wind tunnel airflow, ensuring that the salt mist field in the test section does not drift significantly due to disturbances.

[0061] Based on the adjusted spray rate, the salt spray concentration in the target wind tunnel salt spray test environment is collected again to obtain a new real-time salt spray concentration value. Specifically, the new real-time salt spray concentration value reflects the actual environmental feedback after the spray rate has been adjusted once, and belongs to the feedback update quantity in closed-loop control. Subsequent acquisition is typically achieved through continuous output from the online concentration monitoring device during the test section. After a certain response time following a change in the spray rate, this is reflected in the concentration reading, allowing the control system to obtain an objective evaluation of the adjustment effect. Compared with the concentration value before adjustment, this new concentration value shows whether the deviation has decreased and whether the direction of change is correct. The control system updates subsequent control inputs accordingly, forming a continuous iteration between spray control and concentration monitoring, avoiding error accumulation caused by long-term lack of correction after a one-time adjustment.

[0062] The new real-time salt spray concentration value is compared with the target salt spray concentration value to obtain a new salt spray concentration difference value; Specifically, the new salt spray concentration difference is a deviation signal calculated based on the latest feedback concentration and the target set concentration. It characterizes the remaining deviation between the currently adjusted salt spray field and the target state. This deviation includes both the magnitude and the implied direction, enabling the control system to determine whether the current spray rate is close to the target operating point or whether further correction is needed. By continuously updating the deviation signal, the input of the control system always corresponds to the latest wind tunnel salt spray environment state. Short-term disturbances and long-term drifts are reflected in the new difference value, and subsequent PID calculations can adjust for the latest deviation, making the stable control of salt spray concentration continuous and traceable.

[0063] Based on the new salt spray concentration difference, determine whether the new salt spray concentration difference meets the preset concentration stability condition; Specifically, the concentration stability condition is used to limit the allowable deviation range between the salt spray concentration and the target salt spray concentration value. The new salt spray concentration difference, as a judgment input, can directly reflect whether the current salt spray field has entered a stable operating range. During judgment, the absolute value of the difference can be compared with a preset threshold, or the fluctuation range of the difference can be constrained within a preset time window, ensuring that stability is not just instantaneous but continuous. The threshold setting is matched to the control precision of the target low-concentration salt spray field, avoiding frequent adjustments by the control system within the allowable error range that could cause oscillations, and also avoiding excessively large allowable errors that could lead to uncertainty in the environmental input for subsequent sediment samples. When the difference meets the stability condition, it means that the environmental input intensity can be used as a benchmark for sediment sample collection and subsequent quantitative analysis.

[0064] If the new salt spray concentration difference satisfies the concentration stability condition, then the current spray rate is maintained; Specifically, maintaining the current spray rate means keeping the atomizer output at the current control setpoint without introducing new adjustments, thus ensuring a stable output during salt spray generation. The control system can continue to collect salt spray concentration data in this state to monitor for new disturbances or drift. However, keeping the spray rate constant as long as the difference is within acceptable limits reduces secondary fluctuations caused by control actions, keeping the salt spray concentration stable over a period of time. Synchronous collection of settling liquid samples after the salt spray concentration has stabilized makes it easier to ensure the consistency of samples from each sampling point. The settling rate and average settling liquid concentration obtained from sample analysis are more representative of the surface receiving level under the same environmental input conditions.

[0065] If the new salt spray concentration difference does not meet the concentration stability condition, then return to the step of calculating the spray rate adjustment amount using the PID algorithm based on the salt spray concentration difference, until the new salt spray concentration difference meets the concentration stability condition.

[0066] Specifically, if the new salt spray concentration difference still exceeds the stability condition, it indicates that the salt spray field has not yet converged to the target operating point, potentially indicating insufficient spray adjustment, increased external disturbances, or system response lag. In this case, continuing to the next round of PID calculations can convert the remaining deviation into a new spray rate adjustment. This iterative loop creates an iterative closed loop for spray control, with concentration acquisition, difference updates, and spray rate adjustment repeatedly performed within the same logic chain until the deviation converges to an acceptable range and the salt spray concentration stabilizes near the target level. This closed-loop iteration can resist continuous disturbances caused by dynamic airflow changes in the wind tunnel, suppress long-term drift, and keep the salt spray input intensity under control. This provides a stable and repeatable environmental prerequisite for subsequent sediment sample collection and quantification of key parameters of deposition flux.

[0067] In an alternative embodiment, please refer to Figure 3 The sample analysis and parameter quantification of the sediment sample to obtain key parameters for quantifying the salt deposition flux on the material surface include: The volume or mass of the sediment sample is measured to obtain sediment volume parameters or sediment mass parameters; Specifically, the sedimentation sample is a liquid sample collected simultaneously at each pre-designed sedimentation collection location during the salt spraying phase. Volume or mass parameters characterize the amount of sample collected. Volume can be measured using a graduated cylinder, pipette, etc., while mass can be measured by weighing the sample using an electronic balance and subtracting the container's own weight. Volume or mass serves as a fundamental measurement quantity, which can be used in conjunction with concentration parameters to calculate the amount of salt received at that sampling point within the sampling window, avoiding quantitative deviations caused by relying solely on concentration or volume. Under dynamic airflow conditions in a wind tunnel, the amount of sample collected at each point may vary depending on local salt spray transport and sedimentation conditions. Obtaining volume or mass parameters first solidifies these differences as verifiable data, providing reliable input for subsequent sedimentation amount and sedimentation rate calculations.

[0068] The concentration of the sediment sample was analyzed by conductivity method to obtain the sediment concentration parameters at each preset sediment collection location; Specifically, the conductivity method for concentration analysis utilizes the correlation between solution conductivity and dissolved salt ion concentration to detect the conductivity of the sediment sample, obtain a conductivity measurement, and then convert it into a sediment concentration parameter. This concentration parameter can be understood as the salt content level in the sample. Concentration parameters are obtained for each preset sediment collection location, ensuring that spatial sampling reflects not only differences in collection volume but also differences in salt content. The concentration parameter, combined with the aforementioned volume or mass parameters, provides a quantitative result for salt spray deposition. The conductivity method is suitable for rapid and consistent analysis of multiple samples, reducing operational differences caused by methods such as manual titration, and making concentration data from different sampling points more comparable, facilitating subsequent statistical summarization of the sample area.

[0069] Based on the sediment volume parameter or sediment mass parameter, and combined with the sediment concentration parameter, the salt spray sedimentation amount parameter is calculated. Specifically, the salt spray deposition rate parameter characterizes the total amount of salt actually collected at a predetermined deposition collection location within the sampling window. It can be obtained by multiplying the sample collection volume by the sample concentration. The collection volume can be a volume parameter or a mass parameter, and the concentration parameter corresponds to the salt content level in the sample. During calculation, a correspondence is established according to the sampling points, and the volume or mass and concentration of each point are paired for calculation to obtain the salt spray deposition rate parameter for each point. This allows for direct comparison and statistical analysis of the salt received at different sampling points during the same exposure phase. This deposition rate parameter provides a direct input for subsequent deposition rate calculations, transforming the surface salt reception process, which is difficult to measure directly in the dynamic airflow of the wind tunnel, into a calculable quantitative link, reducing the uncertainty of results caused by spatial fluctuations or differences in sampling volume.

[0070] Based on the salt spray deposition parameters, the salt spray deposition rate at each preset deposition liquid collection location is calculated to obtain the target salt spray deposition rate. Specifically, the salt spray deposition rate characterizes the deposition level of salt spray at the corresponding collection location per unit time. The target salt spray deposition rate is calculated separately for each preset deposition collection location, reflecting the spatial differences in salt spray deposition. The calculation uses the salt spray deposition amount parameter at each point as the core input, while also incorporating the sampling duration parameter for that stage for time normalization. This ensures that different sampling points can be compared on the same time scale even if the deposition amounts differ. Under the condition of synchronous start and stop sampling in stages during wind tunnel testing, the sampling duration is consistent for all sampling points, and the deposition rate directly reflects the spatial distribution and deposition intensity of the salt spray field in the sample area. After converting the deposition amount to the deposition rate, subsequent uniformity assessments, regional statistics, and key parameter outputs are more stable, avoiding incomparable results caused by differences in sampling duration or stage switching.

[0071] The average salt spray settling rate and the average settling liquid concentration of each of the target salt spray settling rates are calculated to obtain the average salt spray settling rate and the average settling liquid concentration. Specifically, the average salt spray settling rate reflects the overall settling level of the sample area during this salt spray exposure phase, while the average settling concentration reflects the representative value of the sample's salt content under synchronous sampling conditions. Both are derived from the statistical summarization of data from multiple preset settling collection locations. The mean is calculated by taking the arithmetic mean of the target salt spray settling rates at each sampling point and the arithmetic mean of the settling concentration parameters at each sampling point, ensuring statistical representativeness rather than dependence on a single location. Taking the mean from multiple points suppresses random fluctuations caused by factors such as local turbulence and local spray transport deviations, converging the discrete data formed by spatial sampling into regional indicators, facilitating repeatable comparisons between different batches of tests and samples of different materials.

[0072] The key parameters are determined based on the average salt spray settling rate and the average settling liquid concentration.

[0073] Specifically, key parameters are used to support the quantitative output of salt deposition flux on the material surface. The average salt spray settling rate and average settling liquid concentration provide a quantitative characterization of salt input in the sample area from two dimensions: the intensity of settling behavior and the salt content of the sample. When determining key parameters, the average values ​​of the above two items can be recorded and stored as the final output, and correlated with the target salt spray concentration value and sampling stage information of this experiment, so that the surface reception results of the material under the controlled salt spray input conditions are traceable. These key parameters are directly derived from the data link of synchronous sampling and unified analysis, which can transform the surface salt reception amount, which is originally difficult to measure directly under the dynamic airflow conditions of the wind tunnel, into a verifiable quantitative indicator, providing a stable data foundation for material durability comparison and subsequent standardized evaluation.

[0074] In an optional embodiment, the step of calculating the salt spray settling rate at each preset settling liquid collection location based on the salt spray settling amount parameter to obtain each target salt spray settling rate includes: Obtain the salt spray deposition parameters and test condition parameters corresponding to each preset sedimentation collection location, wherein the test condition parameters include sampling duration and effective sampling area; Specifically, the salt spray deposition rate parameter corresponds to the total amount of salt accumulated at each preset sedimentation collection location during the same salt spray exposure phase. The sampling duration parameter in the test conditions represents the time window for synchronous operation of the collection device, and the effective sampling area represents the equivalent area actually participating in sedimentation capture at that collection location. Together, they determine the normalized scale when converting deposition rate to deposition rate. The acquisition process establishes a one-to-one correspondence based on the preset sedimentation collection location as an index, and collects the salt spray deposition rate parameter of each location with the corresponding sampling duration and effective sampling area. The sampling duration can be directly obtained from the time sequence record of the salt spraying phase by the central control system, and the effective sampling area can be obtained from the structural parameters of the collection device or preset calibration values, ensuring that the input quantities at each location are consistent and traceable during subsequent calculations, and avoiding distortion of the deposition rate due to parameter mismatch.

[0075] Based on the salt spray deposition parameters and test condition parameters, the target salt spray deposition rates are calculated.

[0076] Specifically, the salt spray deposition rate parameter reflects the total amount of salt actually collected at each preset deposition collection location during a single sampling process. The sampling duration and effective sampling area in the experimental condition parameters correspond to the time and spatial scales of the sampling process, respectively. Therefore, when calculating the target salt spray deposition rate, it is necessary to establish a correspondence between the deposition rate parameter and these two condition parameters. In practice, for each preset deposition collection location, the corresponding salt spray deposition rate parameter is first converted to the sampling duration at that location, transforming the total deposition rate into the deposition rate per unit time. Then, the result is correlated with the effective sampling area at that location, further converting the deposition rate per unit time into the deposition intensity per unit area, thereby obtaining the target salt spray deposition rate at that location. Since the sampling duration and effective sampling area remain controllable or verifiable in the same round of testing, the above conversion process can eliminate the influence of differences in sampling duration and sampling structure size on the results. This gives the target salt spray settling rate obtained at each settling liquid collection location a unified physical meaning, which can be directly used to compare the salt spray input intensity at different locations. It also provides a reliable basis for subsequent calculation of the average salt spray settling rate and evaluation of the uniformity of salt spray spatial distribution, thereby improving the accuracy and repeatability of the quantification results of salt deposition flux on the material surface.

[0077] Example 2 This invention provides a wind tunnel testing system for quantifying the salt deposition flux on material surfaces, used to implement the wind tunnel testing method for quantifying the salt deposition flux on material surfaces as described in Example 1. The system includes: The wind tunnel environment simulation module is used to provide a test section and simulate and adjust the wind speed and environmental parameters within the test section; A salt spray generating module is used to atomize the salt solution and supply salt spray to the test section; The parameter acquisition module includes a salt spray concentration monitoring device set in the test section and multiple salt spray sedimentation collection devices arranged in the sample area, used to acquire salt spray concentration data and collect sedimentation samples. The central control module is connected to the wind tunnel environment simulation module, the salt spray generation module, and the parameter acquisition module. It is used to perform closed-loop control of the salt spray generation module based on the salt spray concentration data and to record the data corresponding to the sedimentation sample to support the quantification of salt deposition flux.

[0078] Specifically, this wind tunnel testing system is modularly structured around three key aspects: controllability, measurability, and traceability of the salt spray environment within the wind tunnel. This transforms the previously unquantifiable salt deposition flux on material surfaces under dynamic airflow conditions into a key parameter output that can be calculated using a standardized approach. The wind tunnel environment simulation module provides a closed test section and a circulating air channel. Within the test section, the wind speed can be continuously adjusted within a preset range, and the temperature and relative humidity can be independently controlled within set intervals. When necessary, simulation modules for solar radiation and background sky radiation can be added to place the sample in dynamic climatic conditions consistent with the target operating conditions, reducing the impact of environmental drift on sedimentation behavior. The salt spray generation module uses a storage tank as the salt solution supply end. The salt solution concentration is configured and maintained within a preset range. An ultrasonic atomizer atomizes the salt solution into salt spray, which enters the test section's nozzle network via a delivery pipeline. The nozzle network introduces the salt spray into the test section, forming a salt spray field covering the sample area, providing a stable source of salt spray for subsequent sedimentation fluid sampling. One end of the parameter acquisition module is equipped with an online salt spray concentration monitoring device, which continuously outputs the salt spray mass concentration data of the test section for real-time characterization of environmental input intensity; the other end has multiple salt spray sedimentation collection devices arranged near the sample to form a spatial sampling array. The collection devices adopt air inlets with windproof and airflow guiding structures and collection containers to realize the synchronous collection of sediment samples in dynamic wind fields. Multiple sampling points can reflect the spatial distribution differences of salt spray and support uniformity assessment and statistical summary. The central control module, consisting of an industrial computer, a PLC controller, and control software, is responsible for the overall system coordination and closed-loop control. It not only coordinates and programs the environmental parameters of the wind tunnel, such as temperature, humidity, wind speed, and radiation, but also reads online salt spray concentration data and compares it with the target salt spray concentration value. It uses a closed-loop feedback control algorithm to dynamically adjust the atomizer spray rate, ensuring that the salt spray concentration in the test section remains stable under disturbance conditions. At the same time, the central control module sends precise synchronization trigger signals to the parameter acquisition module, enabling the sedimentation collection device to start and stop synchronously with the salt spraying stage. This ensures that the sedimentation samples at each location correspond to the same exposure window. Finally, the environmental parameters, control commands, concentration data, and sedimentation data are recorded and stored uniformly. This allows the sedimentation rate, average sedimentation concentration, and other results obtained during the sample analysis stage to be traced back to specific environmental input conditions, supporting the quantitative output of salt deposition flux on the material surface at the system level.

[0079] In an optional embodiment, the salt spray sedimentation collection device has an air inlet and a collection container. The air inlet is provided with a windproof and flow-guiding structure and is configured such that the deviation between the air inlet direction and the dominant airflow direction of the test section is no greater than a preset angle, so as to be suitable for collecting sediment samples in a dynamic wind field.

[0080] Specifically, please see Figure 4 , Figure 4 This demonstration showcases a sedimentation collection device with a windproof and flow-guiding structure and its arrangement within a wind tunnel airflow. The windproof and flow-guiding hood 1, positioned at the top of the device, serves as a flow guide for the air inlet, rectifying the salt mist-containing airflow entering the device and reducing lateral disturbances in a dynamic wind field. A storage tank 2, located below and connected to the windproof and flow-guiding hood 1, collects and stores the liquid samples formed during the sampling process. Sediment 3, formed in the lower part of the storage tank 2, acts as an accumulation area for the collected sediment samples, facilitating subsequent volume or mass measurements and electrical analysis. Concentration analysis using the conductivity method; the guide rod 4 penetrates the windproof guide hood 1 and extends into the liquid storage tank 2, providing a stable flow path so that salt spray droplets entering the guide hood converge and fall along the surface of the guide rod, reducing splashing and re-carrying of droplets under airflow disturbance; the dominant wind direction 5 indicates the main flow direction of the airflow in the wind tunnel, and the windproof guide hood 1 is set to the windward orientation within a preset angle range relative to the dominant wind direction 5, so that the deviation between the device's air intake direction and the dominant airflow direction is controlled, thereby improving the stability and representativeness of collecting sediment samples in dynamic wind fields. The salt spray sedimentation collection device consists of an air inlet and a collection container. The air inlet is used to guide the salt spray-containing airflow into the device, and the collection container is used to receive and collect the droplet samples that settle with the airflow. The windproof guide structure is set at the air inlet to rectify and buffer the airflow entering the device under the dynamic airflow conditions of the wind tunnel. By configuring the air inlet's intake direction to deviate from the dominant airflow direction of the test section by no more than a preset angle, the airflow entering the device is made as close as possible to the external mainstream airflow in both direction and velocity. This avoids airflow separation, backflow, or enhanced turbulence caused by excessive windward angle or leeward arrangement, thereby reducing sampling errors caused by inertial displacement or resuspension of salt spray droplets. This structural configuration allows the collection device to achieve approximately isodynamic sampling even in high-speed or variable-speed wind fields. The formation process of the sedimentation sample more closely resembles the actual salt spray deposition behavior on the sample surface, improving the stability and representativeness of sedimentation sample collection in dynamic wind fields, and providing a reliable basis for subsequent calculations of sedimentation amount and sedimentation rate.

[0081] In an optional embodiment, the central control module is configured to adjust the atomization output of the salt spray generation module based on the deviation between the salt spray concentration data output by the salt spray concentration monitoring device and a preset target value, so as to maintain the stability of the salt spray concentration in the test section.

[0082] Specifically, the central control module uses the real-time salt spray concentration data output by the salt spray concentration monitoring device as an environmental feedback signal. This feedback signal is compared with a preset target salt spray concentration value to obtain the concentration deviation. Based on this deviation, the atomization output of the salt spray generation module is continuously adjusted, allowing the salt spray input intensity to adaptively correct for changes in environmental conditions. Under dynamic airflow conditions in the wind tunnel, fluctuations in wind speed, changes in humidity, or changes in the salt spray transport path can all cause instantaneous shifts in the salt spray concentration within the test section. The central control module reads online concentration data and combines it with a control algorithm to convert the deviation into adjustments to the atomizer's operating parameters, such as adjusting the atomization power or spray rate, to match the salt spray supply with the current airflow conditions, thereby suppressing concentration overshoot or attenuation. Through this closed-loop control method based on real-time monitoring data, the salt spray concentration within the test section can be stably maintained within the target range over a relatively long timescale. This ensures that the salt spray input conditions are always clear and controllable during the sedimentation sample collection phase, reducing the impact of environmental fluctuations on the quantification results of salt deposition flux on the material surface.

[0083] In summary, the embodiments of the present invention provide a wind tunnel testing method and system for quantifying the salt deposition flux on the surface of materials.

[0084] It should be clarified that the present invention is not limited to the specific configurations and processes described above and shown in the figures. For the sake of brevity, detailed descriptions of known methods are omitted here. In the above embodiments, several specific steps are described and shown as examples. However, the method process of the present invention is not limited to the specific steps described and shown. Those skilled in the art can make various changes, modifications, and additions, or change the order of steps, after understanding the spirit of the present invention.

[0085] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0086] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0087] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0088] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0089] It should also be noted that the exemplary embodiments mentioned in this invention describe methods or systems based on a series of steps or apparatus. However, this invention is not limited to the order of the steps described above; that is, the steps can be performed in the order mentioned in the embodiments, or in a different order, or several steps can be performed simultaneously.

[0090] The above description is merely a specific embodiment of the present invention. Those skilled in the art will clearly understand that, for the sake of convenience and brevity, the specific working processes of the systems, modules, and units described above can be referred to the corresponding processes in the foregoing method embodiments, and will not be repeated here. It should be understood that the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A wind tunnel testing method for quantifying the salt deposition flux on material surfaces, characterized in that, The method includes: The uniformity of salt spray spatial distribution in the wind tunnel salt spray test environment is evaluated to obtain a target wind tunnel salt spray test environment that meets the preset salt spray spatial distribution conditions; Based on the preset target salt spray concentration value, the spray rate in the target wind tunnel salt spray test environment is dynamically adjusted, and sediment samples corresponding to each preset sediment collection location in the target wind tunnel salt spray test environment are obtained. The sedimentation fluid sample was analyzed and its parameters were quantified to obtain key parameters for quantifying the salt deposition flux on the material surface.

2. The wind tunnel testing method for quantifying the salt deposition flux on a material surface according to claim 1, characterized in that, The process of evaluating the uniformity of salt spray spatial distribution within the wind tunnel salt spray testing environment to obtain a target wind tunnel salt spray testing environment that meets preset salt spray spatial distribution conditions includes: According to the preset grid layout method, the collection locations of each sediment in the wind tunnel salt spray test environment are obtained; Based on the preset target salt spray conditions, the operating parameters of the wind tunnel salt spray test environment are adjusted to obtain the initial wind tunnel salt spray test environment; The sedimentation rate at each sedimentation collection location within the initial wind tunnel salt spray test environment is obtained by collecting and calculating the sedimentation fluid at each sedimentation collection location. The uniformity of the spatial distribution of the salt spray is evaluated based on the settling rate corresponding to each settling liquid collection location, and the evaluation results are obtained. If the evaluation result indicates that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions, then the wind tunnel salt spray test environment is adjusted, and the adjusted wind tunnel salt spray test environment is used as a new wind tunnel salt spray test environment. The process of adjusting the operating parameters of the wind tunnel salt spray test environment according to the preset target salt spray conditions is repeated until the evaluation result indicates that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions. If the evaluation result indicates that the uniformity of the salt spray spatial distribution meets the preset salt spray spatial distribution conditions, then the current wind tunnel salt spray test environment will be used as the target wind tunnel salt spray test environment.

3. The wind tunnel testing method for quantifying the salt deposition flux on a material surface according to claim 2, characterized in that, The evaluation of the spatial distribution uniformity of the salt spray based on the settling rate corresponding to each of the settling liquid collection locations yields the following evaluation results: Based on the settlement rates described, the average and standard deviation of the settlement rates were calculated. The coefficient of variation for each of the settlement rates is calculated based on the average value and standard deviation. The coefficient of variation is compared with a preset coefficient of variation threshold. If the coefficient of variation is less than or equal to the coefficient of variation threshold, the evaluation result is that the uniformity of salt spray spatial distribution meets the preset salt spray spatial distribution conditions. If the coefficient of variation is greater than the coefficient of variation threshold, the evaluation result is that the uniformity of salt spray spatial distribution does not meet the preset salt spray spatial distribution conditions.

4. The wind tunnel testing method for quantifying the salt deposition flux on a material surface according to claim 1, characterized in that, The step of dynamically adjusting the spray rate within the target wind tunnel salt spray test environment according to a preset target salt spray concentration value, and acquiring sediment samples corresponding to each preset sediment collection location within the target wind tunnel salt spray test environment includes: The salt spray concentration in the target wind tunnel salt spray test environment is collected to obtain the real-time salt spray concentration value; The difference between the real-time salt spray concentration value and the target salt spray concentration value is calculated to obtain the salt spray concentration difference. Based on the salt spray concentration difference, the spray rate is dynamically adjusted using a PID algorithm to maintain a stable salt spray concentration in the target wind tunnel salt spray test environment. In response to a sediment collection signal, a sediment sample is acquired within the target wind tunnel salt spray test environment where the salt spray concentration is stable.

5. The wind tunnel testing method for quantifying the salt deposition flux on a material surface according to claim 4, characterized in that, The step of dynamically adjusting the spray rate using a PID algorithm based on the salt spray concentration difference to maintain a stable salt spray concentration in the target wind tunnel salt spray test environment includes: Based on the salt spray concentration difference, the spray rate adjustment amount is calculated using the PID algorithm. The spray rate is adjusted according to the spray rate adjustment amount to obtain the adjusted spray rate; Based on the adjusted spray rate, the salt spray concentration in the target wind tunnel salt spray test environment is collected again to obtain a new real-time salt spray concentration value. The new real-time salt spray concentration value is compared with the target salt spray concentration value to obtain a new salt spray concentration difference value; Based on the new salt spray concentration difference, determine whether the new salt spray concentration difference meets the preset concentration stability condition; If the new salt spray concentration difference satisfies the concentration stability condition, then the current spray rate is maintained; If the new salt spray concentration difference does not meet the concentration stability condition, then return to the step of calculating the spray rate adjustment amount using the PID algorithm based on the salt spray concentration difference, until the new salt spray concentration difference meets the concentration stability condition.

6. The wind tunnel testing method for quantifying the salt deposition flux on a material surface according to any one of claims 1-5, characterized in that, The sample analysis and parameter quantification of the sedimentation fluid sample yielded key parameters for quantifying the salt deposition flux on the material surface, including: The volume or mass of the sediment sample is measured to obtain sediment volume parameters or sediment mass parameters; The concentration of the sediment sample was analyzed by conductivity method to obtain the sediment concentration parameters at each preset sediment collection location; Based on the sediment volume parameter or sediment mass parameter, and combined with the sediment concentration parameter, the salt spray sedimentation amount parameter is calculated. Based on the salt spray deposition parameters, the salt spray deposition rate at each preset deposition liquid collection location is calculated to obtain the target salt spray deposition rate. The average salt spray settling rate and the average settling liquid concentration of each of the target salt spray settling rates are calculated to obtain the average salt spray settling rate and the average settling liquid concentration. The key parameters are determined based on the average salt spray settling rate and the average settling liquid concentration.

7. The wind tunnel testing method for quantifying the salt deposition flux on a material surface according to claim 6, characterized in that, The calculation of the salt spray settling rate at each preset settling liquid collection location based on the salt spray settling amount parameter, to obtain the target salt spray settling rate, includes: Obtain the salt spray deposition parameters and test condition parameters corresponding to each preset sedimentation collection location, wherein the test condition parameters include sampling duration and effective sampling area; Based on the salt spray deposition parameters and test condition parameters, the target salt spray deposition rates are calculated.

8. A wind tunnel testing system for quantifying the salt deposition flux on material surfaces, characterized in that, For implementing the wind tunnel testing method for quantifying the salt deposition flux on a material surface as described in any one of claims 1-7, the system comprises: The wind tunnel environment simulation module is used to provide a test section and simulate and adjust the wind speed and environmental parameters within the test section; A salt spray generating module is used to atomize the salt solution and supply salt spray to the test section; The parameter acquisition module includes a salt spray concentration monitoring device set in the test section and multiple salt spray sedimentation collection devices arranged in the sample area, used to acquire salt spray concentration data and collect sedimentation samples. The central control module is connected to the wind tunnel environment simulation module, the salt spray generation module, and the parameter acquisition module. It is used to perform closed-loop control of the salt spray generation module based on the salt spray concentration data and to record the data corresponding to the sedimentation sample to support the quantification of salt deposition flux.

9. The wind tunnel testing system for quantifying the salt deposition flux on a material surface according to claim 8, characterized in that, The salt spray sedimentation collection device has an air inlet and a collection container. The air inlet is equipped with a windproof and flow-guiding structure and is configured to ensure that the deviation between the air inlet direction and the main airflow direction of the test section is no greater than a preset angle, so as to be suitable for collecting sediment samples in a dynamic wind field.

10. The wind tunnel testing system for quantifying the salt deposition flux on a material surface according to claim 8, characterized in that, The central control module is configured to adjust the atomization output of the salt spray generation module based on the deviation between the salt spray concentration data output by the salt spray concentration monitoring device and the preset target value, so as to maintain the stability of the salt spray concentration in the test section.

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