Heat management state determination method and device for start-stop process of heat sink

Abstract

The application relates to the technical field of heat absorber control, in particular to a heat absorber start-stop process thermal management state judgment method and device. Distributed temperature, low point acoustic and temperature and meteorological data of a tube panel are collected. The distributed temperature is three-dimensionally reconstructed to generate a thermal cloud picture, segment abnormality and calculate a spatial thermal imbalance comprehensive index and quantify a thermal engineering balance grade. Meteorological data and the balance grade are fused to construct a working condition conversion pre-judgment model of multi-dimensional information fusion, output a working condition conversion coefficient and judge whether to enter a salt dissipation state. In the salt dissipation state, low point acoustic band energy is extracted, combined with a tube wall cooling rate curve, the synchronism of flow energy attenuation and cooling rate turning is detected, and the local salt dissipation state is judged. A thermal health state matrix is established to uniformly map the thermal engineering balance grade and each low point salt dissipation mark. The technical scheme improves the controllability and stability of the heat absorber thermal health, guarantees start-stop safety, high efficiency and life extension.

Description

Technical Field

[0001] This application relates to the field of receiver control technology, specifically to a method and apparatus for determining the thermal management status during receiver start-up and shutdown. Background Technology

[0002] In solar thermal utilization and high-temperature heat transfer systems, the receiver plays a key role in heat collection, transmission and exchange. Its start-up and shutdown process involves frequent switching between two operating conditions: operation and salt removal.

[0003] In existing receiver engineering practices, the determination of thermal management status during start-up and shutdown generally relies on scattered measurement point information and single-dimensional monitoring data, making it difficult to simultaneously characterize the temperature distribution in the tube panel space, the local flow characteristics at low points in the pipeline, and external meteorological changes. The direct result is a lack of a unified quantitative judgment system that can span the entire operation and desalination process during start-up and shutdown. This makes it impossible to provide actionable predictive basis before operating condition transitions, and also makes it difficult to consistently confirm and record the local completion status during the desalination stage. Furthermore, it makes it difficult to compare the status and trace the history between different tube panels and different topological locations, affecting the safety, consistency, and controllability of start-up and shutdown.

[0004] In view of this, this application proposes a method and device for determining the thermal management status during the start-up and shutdown process of a heat absorber. Summary of the Invention

[0005] To achieve the above objectives, this application provides a method and apparatus for determining the thermal management status during the start-up and shutdown process of a heat absorber, the specific technical solution of which is as follows:

[0006] Methods for determining the thermal management status during the start-up and shutdown process of the heat absorber include:

[0007] Distributed temperature data of the receiver tube panel is collected by temperature sensors, as well as acoustic data and low-point temperature data of the receiver pipeline, and meteorological data of the environment in which the receiver is located are obtained, forming a synchronous data stream of spatial thermodynamics, local fluid dynamics and meteorological changes.

[0008] While the receiver is in operation, the distributed temperature data of the receiver is reconstructed in three dimensions and registered in time series to generate a real-time thermal cloud map, segment and identify abnormal temperature areas, calculate a comprehensive index characterizing the degree of spatial thermal imbalance, and standardize and quantify the thermal balance level.

[0009] By integrating meteorological data and thermal equilibrium level, a working condition conversion prediction model based on multi-dimensional information fusion is constructed, and the working condition conversion coefficient is output. Based on the working condition conversion coefficient, it is determined whether to issue a working condition conversion command and control whether the receiver changes from the operating state to the salt-free state.

[0010] In the salt-free state of the receiver, the acoustic signals at each low point of the receiver during salt-free process are acquired and the frequency band energy is extracted. At the same time, the cooling rate curve of the pipe wall temperature is recorded, the synchronous characteristics of the flow energy decay and the cooling rate inflection are detected, and it is determined whether the local salt-free process at the corresponding monitoring point is completed.

[0011] Establish a thermal health status matrix for the receiver, uniformly map the thermal balance level of the receiver to the salt evaporation completion markers at each low point, index it according to the tube panel number and pipeline topology, and perform real-time updates and historical tracing.

[0012] Preferably, distributed temperature data is collected on the surface of the receiver tube screen; acoustic sensors and temperature sensors are deployed at the low points of the receiver pipeline, and acoustic data and temperature data at the low points are collected simultaneously; the solar altitude angle and wind speed change rate are obtained by using the solar tracker and anemometer equipped at the meteorological monitoring station in the receiver field.

[0013] Preferably, while the receiver is in operation, the collected distributed temperature data is reconstructed in three dimensions, a three-dimensional coordinate system is established and the sensor positions are mapped, a continuous temperature field distribution function is constructed using radial basis function interpolation, and time registration is performed to eliminate time deviations.

[0014] Real-time thermal cloud maps are generated based on the registered temperature field data, and the temperature distribution is visualized intuitively by projecting and color mapping using volume rendering technology.

[0015] A gradient-based edge detection algorithm combined with a statistical threshold determination method is used to segment and identify abnormal temperature regions, calculate the spatial gradient of the temperature field, and determine whether the temperature in a local area exceeds the normal range.

[0016] Preferably, a comprehensive evaluation index system is constructed to quantify the degree of spatial thermal inhomogeneity, including: calculating the spatial non-uniformity coefficient of temperature distribution, the kurtosis value of temperature gradient distribution, and the proportion of abnormal areas;

[0017] The spatial non-uniformity coefficient, kurtosis value, and proportion of anomalous areas are weighted and fused to form a comprehensive index of spatial thermal imbalance. Based on the comprehensive index of spatial thermal imbalance, the thermal balance standard is quantitatively divided into multiple levels.

[0018] Preferably, the collected meteorological data are preprocessed and feature extracted, and the data on the rate of change of solar altitude angle and the rate of change of wind speed are smoothed by a sliding window, and meteorological stability indicators are defined.

[0019] The thermal equilibrium level is numerically mapped, and the time derivative of thermal equilibrium is introduced to represent the dynamic change trend of thermal state.

[0020] A fusion decision function is established to integrate meteorological stability indicators, thermal equilibrium, and the dynamic trend of thermal state, and a working condition conversion coefficient is defined.

[0021] Preferably, an adaptive learning mechanism based on historical operating data is introduced to establish a historical operating condition transition event database, and the weight parameters of the operating condition transition coefficients are dynamically adjusted using a Bayesian update method.

[0022] Set a threshold for determining the transition of operating conditions. The threshold for determining the transition of operating conditions is determined by the risk-reward balance principle.

[0023] When the operating condition conversion coefficient exceeds the threshold for determining the operating condition conversion, it is determined that an operating condition conversion is required, and an operating condition conversion control command is generated to control the heat absorber to switch from the operating state to the salt-free state.

[0024] Preferably, when the receiver enters the salt-phobic state, the acoustic signals at each low point are continuously acquired and analyzed in real time.

[0025] Short-time Fourier transform was used for time-frequency analysis, and the frequency bands were divided into multiple characteristic frequency bands for frequency band energy extraction to identify different stages of the salt-repellent process.

[0026] The pipe wall temperature data was acquired, the instantaneous cooling rate curve was constructed and calculated, the five-point difference method was used for numerical differentiation, and the cooling rate curve was piecewise fitted to identify the salt-hydrophobic rate inflection point.

[0027] Preferably, a correlation analysis model is established between acoustic energy attenuation and cooling rate transition, an acoustic energy attenuation index is defined, and the sign transition of the second derivative of the cooling rate is detected.

[0028] A comprehensive criterion for determining whether a heat absorber can achieve salt-phobicity is established. The comprehensive criterion includes: the acoustic energy attenuation index is lower than the set energy attenuation threshold, the cooling rate is lower than the set rate threshold, and the sign of the second derivative of the cooling rate changes.

[0029] A salt-freezing completion confirmation mechanism is established, and the salt-freezing completion status is divided into multiple levels.

[0030] Preferably, a thermal health status matrix of the receiver is constructed, and a multi-dimensional matrix structure is used to store comprehensive status information including thermal equilibrium level value and salt evaporation completion flag.

[0031] Establish a mapping relationship between pipe panel numbers and physical locations, and construct an adjacency matrix based on the pipeline topology; implement a unified mapping mechanism between thermal equilibrium level and salt-free completion indicator, and define a comprehensive health index; establish a real-time update mechanism to reflect the latest operating status of the receiver, and construct a historical data traceability mechanism.

[0032] A thermal management status determination device for the start-up and shutdown process of a heat absorber, which is based on the aforementioned thermal management status determination method for the start-up and shutdown process of a heat absorber, includes: a data acquisition module, a thermal balance assessment module, a status transition module, a shutdown detection module, and a management and maintenance module;

[0033] The data acquisition module collects distributed temperature data of the receiver tube panel through temperature sensors, and also collects acoustic data and low-point temperature data of the receiver pipeline, as well as meteorological data of the environment in which the receiver is located, forming a synchronous data stream of spatial thermodynamics, local fluid dynamics and meteorological changes.

[0034] The heat balance assessment module, under the operating state of the receiver, performs three-dimensional reconstruction and time-series registration of the distributed temperature data of the receiver, generates a real-time thermal cloud map, segments and identifies abnormal temperature areas, calculates a comprehensive index characterizing the degree of spatial thermal imbalance, and standardizes and quantifies the thermal balance level.

[0035] The state transition module integrates meteorological data and thermal equilibrium level to construct a condition transition prediction model based on multi-dimensional information fusion, outputs condition transition coefficients, and determines whether to issue a condition transition command based on the condition transition coefficients to control whether the receiver changes from the operating state to the salt-free state.

[0036] The shutdown detection module acquires acoustic signals at various low points of the receiver during the salt-drying process and extracts the frequency band energy. At the same time, it records the cooling rate curve of the pipe wall temperature, detects the synchronous characteristics of the flow energy decay and the cooling rate inflection, and determines whether the local salt-drying of the corresponding monitoring point is completed.

[0037] The management and maintenance module establishes a thermal health status matrix for the receiver, uniformly mapping the thermal balance level of the receiver to the salt evaporation completion markers at each low point, indexing it by pipe panel number and pipeline topology, and performing real-time updates and historical tracing.

[0038] The beneficial effects of this application are: This application constructs a synchronous data stream covering space thermal, pipeline low-point fluid dynamics and external meteorology, providing a spatiotemporally consistent multi-source information foundation for subsequent judgment, reducing the risk of misjudgment caused by a single measurement dimension, improving data integrity and comparability, and supporting the continuity and accuracy of the entire process monitoring.

[0039] This application achieves intuitive visualization of the temperature field and precise location of anomalies through three-dimensional reconstruction and temporal registration, quantifies the degree of spatial imbalance and forms a standardized level, which facilitates comparison across equipment and time periods; timely identification of abnormal areas, supports early intervention and adjustment of operating strategies, and improves the efficiency of thermal balance management.

[0040] This application integrates meteorological and thermal performance levels to construct a predictive model, outputting operable operating condition conversion coefficients, realizing the transformation from experience-based decision-making to data-driven decision-making; it provides quantitative judgment basis before start-up and shutdown critical points, reducing the risk of unnecessary or delayed switching, and improving start-up and shutdown safety and consistency.

[0041] This application utilizes the synchronous characteristics of acoustic frequency band energy and cooling rate curves to achieve phased identification and completion determination of the salt-removal process, avoiding deviations caused by relying on a single signal; it can precisely confirm the completion of salt-removal at local monitoring points, which helps to shorten the ineffective salt-removal time and reduce energy consumption.

[0042] This application uses a thermal health status matrix to uniformly map thermal performance level and salt-free indicator, and combines topology and number index to achieve structured and traceable status management; it supports real-time updates and historical comparisons, provides quantitative health indicators for operation and maintenance, and facilitates closed-loop management and strategy optimization. Attached Figure Description

[0043] Figure 1 Flowchart of the method for determining the thermal management status during the start-up and shutdown process of the receiver provided in this application;

[0044] Figure 2 The flowchart for evaluating the thermal equilibrium of operating conditions provided in this application;

[0045] Figure 3 The flowchart for predicting and issuing instructions for changing operating conditions provided in this application;

[0046] Figure 4 A flowchart for determining the completion of localized salt-repellent state as provided in this application;

[0047] Figure 5 The structural diagram of the heat absorber start-up and shutdown process thermal management status determination device provided in this application. Detailed Implementation

[0048] To make the above-mentioned objectives, features and advantages of this application more apparent and understandable, the specific embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0049] Many specific details are set forth in the following description in order to provide a full understanding of this application. However, this application may also be implemented in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0050] Secondly, the term "an embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of this application. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single embodiment or an embodiment selectively excluded from other embodiments.

[0051] Example 1

[0052] Reference Figures 1 to 4 This is the first embodiment of the present application, such as Figure 1 As shown, a method for determining the thermal management status during the start-up and shutdown process of a heat absorber is provided.

[0053] Step 1: Collect distributed temperature data of the receiver tube panel through temperature sensors, and collect acoustic data and low-point temperature data of the receiver pipeline, as well as meteorological data of the environment in which the receiver is located, to form a synchronous data stream of spatial thermodynamics, local fluid dynamics and meteorological changes.

[0054] During the start-up and shutdown process of the receiver, a complete multi-source data acquisition system needs to be established first. A distributed temperature sensor array is installed on the surface of the receiver tube panel according to a preset grid layout. The sensors use K-type thermocouples with a temperature measurement range of -200℃ to 1350℃, meeting the temperature monitoring requirements of the receiver under all operating conditions. The receiver tube panel is the direct device for receiving reflected sunlight. Each sensor is evenly arranged to form a uniform monitoring network. For example, the acquisition frequency of the temperature sensors on the surface of the receiver tube panel can be set to 0.1Hz to ensure that the dynamic changes in the temperature field can be captured.

[0055] Temperature and sound monitoring are conducted at the lowest points in the receiver piping system. These lowest points refer to the areas in the receiver piping system where molten salt or other working fluids tend to accumulate due to gravity. These are typically located at the bottom of U-bends, the junctions of horizontal and vertical pipe sections, and the bottom of the header. Acoustic and temperature sensors are deployed simultaneously at these critical low-point locations. The acoustic sensors can be piezoelectric accelerometers with a frequency response range of 10Hz to 10kHz, effectively capturing turbulent noise and bubble bursting sounds generated by molten salt flow. The acoustic sensors can be fixed to the outer surface of the pipe wall using magnetic attraction or strip fastening, and coated with a high-temperature coupling agent to ensure effective acoustic signal transmission.

[0056] Low-point temperature sensors can be surface-mount platinum resistance thermometers, directly attached to the outer surface of the pipe wall and with the gaps filled with thermally conductive silicone grease, and externally covered with insulating material to reduce environmental interference. Temperature and acoustic data are synchronously acquired using the same clock reference to ensure temporal consistency in subsequent multi-source data fusion analysis. Acoustic-thermal coupling monitoring of the receiver's molten salt pipes accurately reflects fluid state changes at low points, providing a reliable basis for precise determination of the receiver's salt-draining process.

[0057] Meteorological data for the receiver field area is obtained through meteorological monitoring stations set up within the field. These stations are equipped with solar trackers and solar intensity meters to measure the solar altitude angle in real time. Wind speed monitoring in the receiver field area was conducted using a three-dimensional ultrasonic anemometer, installed at a height 0.7 times the center height of the receiver. Horizontal and vertical wind speed components were measured, and the wind speed vector magnitude was obtained by integrating these components. Meanwhile, the formula for calculating the rate of change of wind speed is: , This indicates the rate of change of wind speed.

[0058] All collected data is transmitted to a central data processing server via industrial Ethernet, where data quality checks are performed, including range verification, abrupt change detection, and missing value imputation. Abnormal data outside the normal range is automatically flagged and a secondary verification mechanism is triggered. For example, if a temperature sensor reading suddenly jumps from 300℃ to 800℃, the server will cross-validate the data from adjacent sensors. If the temperatures of adjacent sensors are all around 320℃, the data is determined to be abnormal, and interpolation is used to correct it, followed by sensor recalibration.

[0059] This step, by constructing a multi-source synchronous data acquisition system, comprehensively grasps the thermal distribution state of the receiver, the local fluid dynamic characteristics, and changes in the external environment, providing a rich, accurate, and real-time data foundation for subsequent thermal management status determination. This significantly improves the intelligence level of receiver operation monitoring and fault early warning capabilities.

[0060] Step 2: While the receiver is operating, perform 3D reconstruction and time-series registration of the distributed temperature data from the receiver to generate a real-time thermal cloud map. Identify and segment abnormal temperature regions, calculate a comprehensive index characterizing the degree of spatial thermal imbalance, and standardize the thermal equilibrium level. (See also...) Figure 2 This is a flowchart for evaluating the thermal equilibrium of the operating status in this step.

[0061] During receiver operation, the collected distributed temperature data undergoes three-dimensional spatial reconstruction. First, a three-dimensional coordinate system is established for the receiver tube panel, with the geometric center of the panel as the origin, the horizontal direction as the X-axis, the vertical direction as the Y-axis, and the normal depth direction as the Z-axis. The physical location of each temperature sensor is mapped onto the three-dimensional coordinate system, forming a discrete set of temperature sampling points. Radial basis function interpolation is then used to spatially interpolate these discrete temperature points, constructing a continuous temperature field distribution function. ,in Indicates the temperature value. Represents spatial coordinates, To represent time, a Gaussian kernel function is introduced as a weighting factor during the interpolation of the temperature field distribution function to ensure a smooth transition of the temperature field and preservation of local features.

[0062] Real-time thermal cloud maps are generated based on the registered temperature field data, and volume rendering technology is used to project the three-dimensional temperature field onto a two-dimensional display plane. Temperature values ​​are converted into RGB color values ​​through a color mapping table, with the temperature range mapped sequentially from low to high to blue, green, yellow, and red, forming an intuitive visualization of thermal distribution. The cloud map update frequency can be set to once per minute, and can be customized to achieve dynamic monitoring for different needs. The visualization method enables operators to quickly identify temperature distribution patterns and abnormal areas.

[0063] To identify areas of temperature anomalies, a gradient-based edge detection algorithm combined with a statistical thresholding method is used to calculate the spatial gradient of the temperature field. When the gradient value exceeds a set threshold, it is marked as a potential anomaly boundary. Simultaneously, the temperature statistical characteristics of the local area are calculated, including the mean. and standard deviation ,in Indicates the first A local area. When the temperature value of a certain area meets... The area was identified as an abnormal region at that time. Indicates local temperature. and These represent the global temperature mean and standard deviation, respectively. This is the anomaly detection coefficient. For example, if the global average temperature of the receiver is 550℃ and the standard deviation is 30℃ when it is operating normally, if the temperature in a certain local area reaches above 640℃ or below 460℃, it is identified as a temperature anomaly area.

[0064] To quantify the degree of spatial thermal inhomogeneity and construct a comprehensive evaluation index system, the spatial non-uniformity coefficient of temperature distribution is first calculated. ,in Indicates the spatial non-uniformity coefficient. Indicates the standard deviation of space temperature. This represents the spatial temperature mean; then the kurtosis value of the temperature gradient distribution is calculated. ,in Indicates the kurtosis of the gradient. Represents the gradient value. and Let these represent the mean and standard deviation of the gradient, respectively. This represents the mathematical expectation operation; finally, the proportion of abnormal regions is calculated. ,in Indicates the percentage of abnormal areas. Indicates the volume of the abnormal region. This indicates the total volume of the heat absorber.

[0065] The above three indicators are weighted and fused to form a comprehensive indicator of spatial thermal imbalance: ,in This represents a comprehensive index of thermal imbalance. , , , Let be the weighting coefficient, satisfying The weighting coefficients are determined using the analytic hierarchy process (AHP), and can also be assigned values ​​based on the degree of influence of each indicator on the safe operation of the receiver. For example, based on the comprehensive indicator value... Thermal uniformity is classified into five levels: Excellent ( ),good( ),generally( Poor ),Danger( ).

[0066] This step, through multi-dimensional temperature field analysis and quantitative evaluation methods, comprehensively characterizes the thermal distribution features of the receiver during operation. It can promptly identify local overheating or undercooling areas, providing accurate condition assessment basis for operation control, effectively preventing thermal stress damage and operational failures caused by uneven temperature distribution, and improving the safety and economy of receiver operation.

[0067] Step 3: Integrate meteorological data and thermal equilibrium level to construct a condition transition prediction model based on multi-dimensional information fusion. Output condition transition coefficients, and determine whether to issue a condition transition command based on these coefficients to control whether the receiver transitions from the operating state to the salt-free state. See also Figure 3 This is a flowchart for predicting operating conditions and issuing instructions in this step.

[0068] Meteorological data are preprocessed and feature extracted. The collected data on the rate of change of solar altitude angle and wind speed are smoothed using a sliding window with a window length of 5 minutes to eliminate the impact of instantaneous disturbances on the judgment. Meteorological stability indices are defined. ,in Indicators representing meteorological stability Indicates the rate of change of solar altitude angle. Indicates the rate of change of wind speed. and These are normalization coefficients, used to adjust the weights of the effects of changes in solar altitude angle and wind speed on stability, respectively. When meteorological conditions change drastically... A value close to 0 indicates significant external disturbance; when meteorological conditions are stable, The value approaches 1.

[0069] The thermal equilibrium level is numerically mapped: excellent level to 1.0, good level to 0.8, average level to 0.6, poor level to 0.4, and dangerous level to 0.2. This mapping intuitively shows that the better the thermal state, the higher the corresponding numerical value. The time derivative of thermal equilibrium is also introduced. ,in Indicates the rate of change of thermal equilibrium. This represents the thermal equilibrium value at the current moment. The sampling time interval is denoted as . The time derivative of thermal equilibrium reflects the dynamic trend of thermal state changes; a positive value indicates an improvement in thermal state, while a negative value indicates a deterioration in thermal state.

[0070] A fusion decision function for predicting operating condition transitions is established, comprehensively considering meteorological stability, thermal equilibrium, and their changing trends. The operating condition transition coefficient is defined as follows: The specific calculation formula is as follows: ,in Indicates the operating condition conversion factor. , , For the weight parameters, satisfying . This reflects the promoting effect of meteorological instability on operating condition transitions. This reflects the need for a change in operating conditions due to poor thermal performance. Then consider the impact of the trend of deterioration in thermal condition; through The function ensures that the operating condition conversion factor is increased only when meteorological stability and thermal equilibrium show a deteriorating trend.

[0071] To improve the accuracy of the operating condition transition prediction model, an adaptive learning mechanism based on historical operating data is introduced. A historical operating condition transition event database is established, recording the meteorological conditions, thermal state, and operational effects before each transition. A Bayesian update method is used to dynamically adjust the weight parameters; the update formula is as follows: ,in Indicates the updated number Each weight, This indicates the weights before the update. Indicates the learning rate. This indicates the actual performance score. The score represents the prediction effect. The constructed adaptive mechanism enables the working condition transition prediction model to continuously optimize decision parameters based on actual operating experience.

[0072] Set the threshold for determining operating condition transitions When the operating condition conversion coefficient When this occurs, a change in operating condition is deemed necessary. The threshold is determined using a risk-reward balance principle, comprehensively considering the necessity of salt-free operation and the equipment wear and tear caused by frequent switching. For example, when… When set to 0.5, if the meteorological stability index at a certain moment... (Indicating significant weather changes), thermal equilibrium value (Corresponding to poorer level), rate of change in thermal equilibrium (Indicating a deteriorating state), the weight parameters are set as follows: , , Then the calculation yields ,because If so, a working condition change command will be issued.

[0073] When it is determined that a change in operating condition is required, a change in operating condition control command is generated, and the receiver is switched from the operating turntable to the salt-free state. At the same time, the change in operating condition early warning mechanism is activated to notify the operators in advance to make the corresponding preparations, so as to achieve a safe switch-off in human-machine collaboration.

[0074] This step, through this multi-dimensional information fusion prediction method, can comprehensively consider changes in the external environment and the internal thermal state, accurately grasp the best time for the transition of operating conditions, avoid the one-sidedness and lag of judgment based on a single indicator, reduce unnecessary switching of operating conditions, extend the service life of equipment, and ensure that it can enter the salt-free state in a timely manner when necessary, thus ensuring the safe and stable operation of the receiver.

[0075] Step 4: Under the salt-free condition of the receiver, acquire the acoustic signals at various low points during salt-free operation and extract the frequency band energy. Simultaneously, record the cooling rate curve of the pipe wall temperature, detect the synchronous characteristics of the flow energy attenuation and cooling rate inflection, and determine whether the local salt-free operation at the corresponding monitoring point is complete. (See also...) Figure 4 This is a flowchart for determining the completion of local salt-freeing in this step.

[0076] After the receiver enters the salt-repellent state, it is necessary to continuously collect and analyze the acoustic signals at each low point of the receiver in real time to ensure the safety and stability of the salt-repellent process.

[0077] During the salt-draining process, the turbulence noise generated by the molten salt flow inside the pipe, the sound of bubble bursting, and the sound of solid-liquid interaction constitute a complex acoustic characteristic spectrum. A short-time Fourier transform method is used to perform time-frequency analysis on the acoustic signals, transforming the time-domain signals... Transform to the time-frequency domain to obtain the time-frequency spectrum. ,in Represents the time spectrum. The imaginary unit, Represents the original acoustic signal. Represents the window function. Indicates frequency, This represents the integral variable. The window function uses a Hamming window, with a window length that can be set to 256 sampling points and an overlap rate of 50% to ensure a balance between time and frequency resolution.

[0078] time spectrum Energy extraction was performed by dividing the frequency bands into three characteristic bands: the low frequency band (10Hz-500Hz) mainly reflects large-scale flow characteristics, the mid frequency band (500Hz-3kHz) corresponds to turbulent mixing and bubble motion, and the high frequency band (3kHz-10kHz) contains information on solid particle collisions and microbubble bursts.

[0079] Calculate the energy distribution of each frequency band ,in Indicates the first Energy of each frequency band and They represent the first By monitoring the temporal evolution characteristics of the energy in each frequency band, the lower and upper limits of each frequency band can be used to identify different stages of the salt-hydrophobic process.

[0080] Simultaneously record pipe wall temperature data, construct cooling rate curves, and calculate instantaneous cooling rate. ,in Indicates the cooling rate. The tube wall temperature is represented by a five-point difference method for numerical differentiation calculation to reduce the impact of measurement noise. The cooling rate curve is piecewise fitted to identify the rate inflection point. In the initial stage of salination, the tube wall loses its heat source due to the rapid discharge of molten salt, resulting in a high cooling rate. When the molten salt is basically emptied, the cooling rate will show a significant decrease. This inflection point is an important characteristic for determining the completion of salination.

[0081] Establish a correlation analysis model between acoustic energy attenuation and the cooling rate transition, and define an acoustic energy attenuation index. ,in Indicates the acoustic energy attenuation index. express Total acoustic energy at any given moment This represents the total acoustic energy at the start of the salt spray test; when Drop to the set energy decay threshold The following indicates a significant decrease in fluid kinetic energy. Simultaneously, the second derivative of the cooling rate is measured. When it changes from a negative value to a positive value, it indicates that the molten salt cooling process has entered a slow phase.

[0082] A comprehensive criterion for determining the completion of salt-phobicity should be established. Completion of salt-phobicity requires the simultaneous fulfillment of three conditions: 1) Acoustic energy attenuation index. ,in 1) Energy decay threshold; 2) Cooling rate ,in For the rate threshold; 3) the sign of the second derivative of the cooling rate changes. For example, if monitoring at a low point in the receiver duct shows that the total acoustic energy is 85dB at the beginning of the salt-absorbing process, and drops to 32dB after 12 minutes, the calculated... Simultaneously, the pipe wall temperature decreased from 320℃ to 180℃, the cooling rate decreased from the initial 15℃ / min to 2℃ / min, and the second derivative changed from -0.8℃ / min² to 0.2℃ / min². When set... , When the temperature reaches ℃ / min, the monitoring point meets the criteria for salt-free operation.

[0083] A tiered salt removal completion confirmation mechanism is implemented, classifying the salt removal completion status into three levels: preliminary completion, basic completion, and complete completion. Preliminary completion indicates that the main molten salt has been removed; basic completion indicates that the amount of residual molten salt is extremely small; and complete completion indicates that the pipeline is completely emptied. Each level corresponds to different judgment criteria and subsequent operation strategies to achieve refined management of the absorber salt removal process.

[0084] This step achieves non-destructive real-time monitoring of the salt-phlosion process through the coordinated analysis of acoustic and temperature signals, avoiding the drawbacks of traditional methods that require shutdown for inspection, and significantly improving salt-phlosion efficiency and accuracy. Based on a multi-physics coupling-based determination method, this step can accurately capture the dynamic characteristics of the salt-phlosion process, providing reliable technical support for the safe switching and efficient operation of the receiver.

[0085] Step 5: Establish a thermal health status matrix for the receiver, uniformly map the thermal balance level of the receiver to the salt evaporation completion markers at each low point, index it according to the tube panel number and pipeline topology, and perform real-time updates and historical tracing.

[0086] Construct a thermal health state matrix for the receiver, and use a multi-dimensional matrix structure to store and manage the comprehensive state information of the receiver; define the state matrix. ,in Indicates the first The first tube screen Each monitoring location is The state value at time t, For the screen number index, To monitor the location index, This is a time-indexed system. Rows in the matrix correspond to different pipe screens, columns to monitoring locations, and the depth dimension records time-series data. Each matrix element contains two key pieces of information: a thermal equilibrium level value and a salt-evaporation completion flag, encapsulated and stored using a composite data structure.

[0087] A mapping relationship between tube panel numbers and physical locations is established, and the system is coded according to the actual arrangement of the receiver. For example, the tube panel numbers use a three-segment coding rule: the first segment indicates the orientation, the second segment indicates the vertical hierarchy, and the third segment indicates the horizontal sequence number. For instance, the number "N-3-5" represents the 5th tube panel on the 3rd layer on the north side. Each tube panel has multiple monitoring location sub-nodes, including tube panel surface temperature monitoring points, low-point acoustic monitoring points, and valve position monitoring points. This hierarchical coding system achieves an accurate mapping from physical space to data space.

[0088] For the pipeline topology, construct an adjacency matrix. ,in Indicates tube screen With tube screen The connection between them, when the two are directly connected ,otherwise The adjacency matrix can be used to quickly represent heat transfer paths and fault propagation links. During state updates, topological relationships are used for correlation analysis. When an anomaly occurs in a certain tube panel, the state of its adjacent tube panels can be checked, enabling early warning of faults and prediction of propagation paths.

[0089] Implement a unified mapping mechanism between thermal balance levels and salt-phreatic clearance completion indicators. The five levels of thermal balance (Excellent, Good, Average, Poor, Dangerous) are coded as 5, 4, 3, 2, and 1 respectively. Salt-phreatic clearance completion status is coded as a binary symbol, where 1 indicates completion and 0 indicates incomplete or in progress. Define a comprehensive health index. ,in Indicates the first The first tube screen The overall health of each location This represents the normalized thermal equilibrium level value. This indicates the completion of salt-free processing. and Let be the weighting coefficient, satisfying The unified mapping mechanism between the thermal equilibrium level and the salt-free completion indicator integrates the state information of multi-source heterogeneity into the same evaluation system.

[0090] A real-time update mechanism is established. When the sensor acquisition frequency is set to 0.1Hz, the data refresh cycle is set to 10 seconds to ensure the state matrix reflects the latest operating status of the receiver. The update process adopts an incremental strategy, modifying only the changed matrix elements to reduce computational overhead. A state change rate is defined. ,in Represents the rate of change of state. This indicates the number of monitoring points that changed per unit of time. Indicates the total number of monitoring points. When... Exceeding the set state change rate threshold When this occurs, a global state assessment is triggered, and the overall health index of the receiver is recalculated; the state change rate threshold is also considered. It can be set to a large value to avoid frequent global state evaluations.

[0091] A historical data traceability system is constructed, using a timestamp index to store the historical status matrix. For example, a data storage strategy is set: real-time data retains complete records for the most recent 72 hours, daily statistics retain the most recent 30 days, and monthly summary data is stored long-term. Historical data employs compression storage technology, using the LZ77 algorithm to reduce storage space usage while ensuring data integrity. A fast retrieval mechanism is established, supporting multi-dimensional queries of historical records by time period, management screen number, status level, and other dimensions.

[0092] Implement state trend analysis functionality, identifying state evolution patterns through statistical analysis of historical data. Calculate state stability indices. ,in Indicates stability index, This indicates the number of sampling points within the statistical period. express Health value at any time This represents the average health level. For example, a certain screen's health levels over the past 24 hours were 4.2, 4.1, 3.9, 4.0, and 3.8, with a calculated average of 4.0. This is a stability index. This indicates that the tube screen is in a relatively stable state.

[0093] Establish an abnormal status alarm mechanism to automatically generate alarm information when a sharp decline in health or salinity abnormalities are detected. The alarm information includes the location, type, and severity of the abnormality, and is simultaneously communicated to operators via a visual interface and audible / visual alarms. Establish a tiered response mechanism to trigger different levels of emergency plans based on the severity of the abnormality.

[0094] This step, by establishing such a comprehensive thermal health status matrix management mechanism, achieves full monitoring and scientific management of the receiver's operating status, provides data support for operational decisions, improves the accuracy of fault diagnosis and the pertinence of maintenance plans, can effectively extend the service life of the receiver equipment, and ensure the long-term safe and stable operation of the receiver.

[0095] Example 2

[0096] A second embodiment of this application provides a start-up process for a heat absorber in a functional operating state.

[0097] The operation of the absorber is divided into four stages: preheating before startup, standby, operation, salt removal, and shutdown.

[0098] The preheating conditions include: approximately 4 hours before sunrise, the molten salt pipeline electric heat tracing system is turned on by controlling the configuration power group according to the actual electric heat tracing power; the meteorological monitoring system determines that the operating conditions are met on that day; the wind speed is less than the set value of 18m / s (the average wind speed at a height of 10m over 10 minutes); the meteorological conditions during the preheating state of the receiver can be determined by either a cloud monitoring system or manual judgment.

[0099] Since the heat absorber system is the potential freezing point of molten salt, electric heat tracing systems (including containers, pipes, valves, and others) are used to prevent molten salt from freezing and for daily preheating; electric heat tracing systems have the ability to heat molten salt pipes, valves, and containers and maintain them at 300°C.

[0100] The preheating state is triggered by starting the electric heat tracing system; when DNI is greater than 50W / m2, the mirror field preheating absorber is started.

[0101] The conditions for ending the preheating state include that the temperature of the molten salt piping system is greater than 300°C and the average temperature of all absorber panels is greater than 300°C.

[0102] The conditions for triggering standby mode include: the meteorological system determines that operating conditions are met; molten salt pipeline preheating is completed; wind speed is less than the set value of 18 m / s (average wind speed at a height of 10 m over 10 minutes); the receiver system equipment diagnostics are normal; and the air compressor system has established pressure. Meteorological conditions for receiver standby mode can be determined using either a cloud monitoring system or manually.

[0103] The standby state trigger actions include starting the cold salt pump and establishing circulation in the riser, absorber bypass pipe, and downcomer.

[0104] The conditions for ending the standby state include the establishment of a liquid level in the outlet buffer tank.

[0105] The triggering conditions for the operating status include: the meteorological function determines that the receiver is ready for salt inlet; the receiver panel preheating is complete; the wind speed is less than the set value of 18 m / s (the average wind speed at a height of 10 m over 10 minutes); the receiver system equipment diagnostics are normal; and the air compressor system has established pressure. The meteorological conditions for receiver operation can be determined using either a cloud monitoring system or manual assessment.

[0106] The operational actions include: opening the absorber exhaust and desalination valves to allow salt to enter the absorber body; closing the exhaust and desalination valves after the absorber body has been fed with salt, establishing a serial flow in the absorber; gradually inputting mirror field energy until all mirror field energy is input; adjusting the absorber inlet flow rate to maintain the absorber outlet salt temperature at 565℃; when the absorber outlet salt temperature is less than 400℃, it enters the cold salt tank, and when it is greater than 400℃, it enters the hot salt tank. The 400℃ switching temperature can be adjusted according to the design temperature of the storage tank.

[0107] The outlet molten salt temperature of the absorber is regulated by the frequency converter of the molten salt pump. When there is a deviation in the flow rate between the two branches of the absorber, it is regulated by the inlet regulating valve.

[0108] The conditions for ending the operation include the molten salt temperature at the absorber outlet reaching 565°C.

[0109] The triggering conditions for the salt-free state include: the meteorological function determines that the receiver does not meet the operating conditions; the solar altitude angle is less than 5°; and the wind speed is greater than the set value of 18m / s (the average wind speed at a height of 10m over 10 minutes).

[0110] The actions for salt removal include: defocusing the mirror field, maintaining the receiver at 300°C for a small number of heliostats; turning off the cold salt pump; and opening the vent valve and salt removal valve to remove salt.

[0111] The conditions for ending the salt removal process include the completion of salt removal in the absorber (30 minutes after salt removal, and the total molten salt mass in the storage tank is restored to the level of the previous day's shutdown).

[0112] The conditions for triggering the shutdown state include the completion of salt evaporation.

[0113] The trigger actions for shutdown include: the mirror field returning to its initial position; and the electric heat tracing system shutting down (electric heat tracing of valves can be retained).

[0114] The conditions for ending the shutdown include that the mirror field and electric heat tracing system have been shut down.

[0115] Example 3

[0116] Reference Figure 5 This is the third embodiment of the present application, which provides a device for determining the thermal management status during the start-up and shutdown process of a heat absorber.

[0117] The device includes: a data acquisition module, a thermal balance assessment module, a state transition module, a shutdown detection module, and a management and maintenance module.

[0118] The data acquisition module collects distributed temperature data of the receiver tube panel through temperature sensors, as well as acoustic data and low-point temperature data of the receiver pipeline, and meteorological data of the environment in which the receiver is located, forming a synchronous data stream of spatial thermal, local fluid dynamics and meteorological changes.

[0119] The heat balance assessment module, under the operating state of the receiver, performs three-dimensional reconstruction and time-series registration of the distributed temperature data of the receiver, generates a real-time thermal cloud map, segments and identifies abnormal temperature areas, calculates a comprehensive index characterizing the degree of spatial thermal imbalance, and standardizes and quantifies the thermal balance level.

[0120] The state transition module integrates meteorological data and thermal equilibrium level to construct a condition transition prediction model based on multi-dimensional information fusion, outputs condition transition coefficients, and determines whether to issue a condition transition command based on the condition transition coefficients to control whether the receiver changes from the operating state to the salt-free state.

[0121] The shutdown detection module acquires acoustic signals at various low points of the receiver during the salt-drying process and extracts the frequency band energy. At the same time, it records the cooling rate curve of the pipe wall temperature, detects the synchronous characteristics of the flow energy decay and the cooling rate transition, and determines whether the local salt-drying at the corresponding monitoring point is completed.

[0122] The management and maintenance module establishes a thermal health status matrix for the receiver, uniformly mapping the thermal balance level of the receiver to the salt evaporation completion markers at each low point, indexing it by pipe panel number and pipeline topology, and performing real-time updates and historical tracing.

[0123] In the embodiments provided in this application, it should be understood that the disclosed apparatus and methods can be implemented in other ways. The apparatus embodiments described above are merely illustrative. For example, the division of units is only a logical functional division, and in actual implementation, there may be other division methods. Furthermore, multiple units or components may be combined or integrated into another system, or some features may be ignored or not executed. Additionally, the displayed or discussed mutual couplings or direct couplings or communication connections may be through some communication interfaces; indirect couplings or communication connections between devices or units may be electrical, mechanical, or other forms.

[0124] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments under the guidance of this application without departing from the spirit and scope of protection of the claims. All of these variations are within the protection scope of this application.

Claims

1. A method for determining the thermal management status during the start-up and shutdown process of a heat absorber, characterized in that, include: Distributed temperature data of the receiver tube panel is collected by temperature sensors, as well as acoustic data and low-point temperature data of the receiver pipeline, and meteorological data of the environment in which the receiver is located, forming a synchronous data stream of spatial thermodynamics, local fluid dynamics and meteorological changes. While the receiver is in operation, the distributed temperature data of the receiver is reconstructed in three dimensions and registered in time series to generate a real-time thermal cloud map, segment and identify abnormal temperature areas, calculate a comprehensive index characterizing the degree of spatial thermal imbalance, and standardize and quantify the thermal balance level. By integrating meteorological data and thermal equilibrium level, a working condition conversion prediction model based on multi-dimensional information fusion is constructed, and the working condition conversion coefficient is output. Based on the working condition conversion coefficient, it is determined whether to issue a working condition conversion command and control whether the receiver changes from the operating state to the salt-free state. In the salt-free state of the receiver, the acoustic signals at each low point of the receiver during salt-free process are acquired and the frequency band energy is extracted. At the same time, the cooling rate curve of the pipe wall temperature is recorded, the synchronous characteristics of the flow energy decay and the cooling rate inflection are detected, and it is determined whether the local salt-free process at the corresponding monitoring point is completed. Establish a thermal health status matrix for the receiver, uniformly map the thermal balance level of the receiver to the salt evaporation completion markers at each low point, index it according to the tube panel number and pipeline topology, and perform real-time updates and historical tracing.

2. The method for determining the thermal management status during the start-up and shutdown process of a heat absorber according to claim 1, characterized in that, Distributed temperature data is collected on the surface of the receiver tube screen; acoustic and temperature sensors are deployed at the low points of the receiver pipeline, and acoustic and temperature data at the low points are collected simultaneously; the solar altitude angle and wind speed change rate are obtained by using the solar tracker and anemometer equipped at the meteorological monitoring station in the receiver field.

3. The method for determining the thermal management status during the start-up and shutdown process of a heat absorber according to claim 2, characterized in that, While the receiver is in operation, the collected distributed temperature data is reconstructed in three dimensions, a three-dimensional coordinate system is established and the sensor positions are mapped, a continuous temperature field distribution function is constructed using radial basis function interpolation, and time registration is performed to eliminate time deviation. Real-time thermal cloud maps are generated based on the registered temperature field data, and the temperature distribution is visualized intuitively by projecting and color mapping using volume rendering technology. A gradient-based edge detection algorithm combined with a statistical threshold determination method is used to segment and identify abnormal temperature regions, calculate the spatial gradient of the temperature field, and determine whether the temperature in a local area exceeds the normal range.

4. The method for determining the thermal management status during the start-up and shutdown process of a heat absorber according to claim 3, characterized in that, A comprehensive evaluation index system is constructed to quantify the degree of spatial thermal imbalance, including: calculating the spatial non-uniformity coefficient of temperature distribution, the kurtosis value of temperature gradient distribution, and the proportion of abnormal areas; The spatial non-uniformity coefficient, kurtosis value, and proportion of anomalous areas are weighted and fused to form a comprehensive index of spatial thermal imbalance. Based on the comprehensive index of spatial thermal imbalance, the thermal balance standard is quantitatively divided into multiple levels.

5. The method for determining the thermal management status during the start-up and shutdown process of a heat absorber according to claim 4, characterized in that, The collected meteorological data were preprocessed and features were extracted. The data on the rate of change of solar altitude angle and the rate of change of wind speed were smoothed by a sliding window, and meteorological stability indices were defined. The thermal equilibrium level is numerically mapped, and the time derivative of thermal equilibrium is introduced to represent the dynamic change trend of thermal state. A fusion decision function is established to integrate meteorological stability indicators, thermal equilibrium, and the dynamic trend of thermal state, and a working condition conversion coefficient is defined.

6. The method for determining the thermal management status during the start-up and shutdown process of a heat absorber according to claim 5, characterized in that, An adaptive learning mechanism based on historical operating data is introduced to establish a database of historical operating condition transition events, and a Bayesian update method is used to dynamically adjust the weight parameters of the operating condition transition coefficients. Set a threshold for determining the transition of operating conditions. The threshold for determining the transition of operating conditions is determined by the risk-reward balance principle. When the operating condition conversion coefficient exceeds the threshold for determining the operating condition conversion, it is determined that an operating condition conversion is required, and an operating condition conversion control command is generated to control the heat absorber to switch from the operating state to the salt-free state.

7. The method for determining the thermal management status during the start-up and shutdown process of a heat absorber according to claim 6, characterized in that, When the receiver enters the salt-phobic state, the acoustic signals at each low point are continuously acquired and analyzed in real time. Short-time Fourier transform was used for time-frequency analysis, and the frequency bands were divided into multiple characteristic frequency bands for frequency band energy extraction to identify different stages of the salt-repellent process. The pipe wall temperature data was acquired, the instantaneous cooling rate curve was constructed and calculated, the five-point difference method was used for numerical differentiation, and the cooling rate curve was piecewise fitted to identify the salt-hydrophobic rate inflection point.

8. The method for determining the thermal management status during the start-up and shutdown process of a heat absorber according to claim 7, characterized in that, A correlation analysis model for acoustic energy attenuation and cooling rate transition is established, an acoustic energy attenuation index is defined, and the sign change of the second derivative of the cooling rate is detected. A comprehensive criterion for determining whether a heat absorber can achieve salt-phobicity is established. The comprehensive criterion includes: the acoustic energy attenuation index is lower than the set energy attenuation threshold, the cooling rate is lower than the set rate threshold, and the sign of the second derivative of the cooling rate changes. A salt-freezing completion confirmation mechanism is established, and the salt-freezing completion status is divided into multiple levels.

9. The method for determining the thermal management status during the start-up and shutdown process of a heat absorber according to claim 8, characterized in that, A thermal health status matrix for the receiver is constructed, and a multi-dimensional matrix structure is used to store comprehensive status information including thermal equilibrium level values ​​and salt-free completion flags. Establish a mapping relationship between pipe panel numbers and physical locations, and construct an adjacency matrix based on the pipeline topology; implement a unified mapping mechanism between thermal equilibrium level and salt-free completion indicator, and define a comprehensive health index; establish a real-time update mechanism to reflect the latest operating status of the receiver, and construct a historical data traceability mechanism.

10. A device for determining the thermal management status during the start-up and shutdown process of a heat absorber, which is based on the method for determining the thermal management status during the start-up and shutdown process of a heat absorber as described in any one of claims 1 to 9, characterized in that, include: The system includes a data acquisition module, a thermal balance assessment module, a state transition module, a shutdown detection module, and a management and maintenance module. The data acquisition module collects distributed temperature data of the receiver tube panel through temperature sensors, and also collects acoustic data and low-point temperature data of the receiver pipeline, as well as meteorological data of the environment in which the receiver is located, forming a synchronous data stream of spatial thermodynamics, local fluid dynamics and meteorological changes. The heat balance assessment module, under the operating state of the receiver, performs three-dimensional reconstruction and time-series registration of the distributed temperature data of the receiver, generates a real-time thermal cloud map, segments and identifies abnormal temperature areas, calculates a comprehensive index characterizing the degree of spatial thermal imbalance, and standardizes and quantifies the thermal balance level. The state transition module integrates meteorological data and thermal equilibrium level to construct a condition transition prediction model based on multi-dimensional information fusion, outputs condition transition coefficients, and determines whether to issue a condition transition command based on the condition transition coefficients to control whether the receiver changes from the operating state to the salt-free state. The shutdown detection module acquires acoustic signals at various low points of the receiver during the salt-drying process and extracts the frequency band energy. At the same time, it records the cooling rate curve of the pipe wall temperature, detects the synchronous characteristics of the flow energy decay and the cooling rate inflection, and determines whether the local salt-drying of the corresponding monitoring point is completed. The management and maintenance module establishes a thermal health status matrix for the receiver, uniformly mapping the thermal balance level of the receiver to the salt evaporation completion markers at each low point, indexing it by pipe panel number and pipeline topology, and performing real-time updates and historical tracing.

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