An air exhaust control method and system for preventing cavitation of an energy-saving water pump suction pipe

Abstract

The application relates to the technical field of exhaust control, and discloses an exhaust control method and system for preventing cavitation of an energy-saving water pump suction pipe, which comprises the following steps: segmentally dividing the suction pipeline of the energy-saving water pump based on a flow direction, correlating and segmentally analyzing the data of each suction pipe section based on a spatial sequence, determining the gas characteristic values of each suction pipe section, performing difference calculation and change direction determination on the gas characteristic values of adjacent suction pipe sections, merging and determining a plurality of gas sections for the suction pipe sections of the same type, determining a gas aggregation section for a gas section meeting the gas characteristic value condition and located downstream of the suction direction, sequencing each exhaust valve based on the gas characteristic values, judging whether to adjust the opening sequence based on the occurrence frequency of historical data in a historical database, verifying the adjusted opening sequence based on a valve control model, and controlling the opening of each exhaust valve according to the verification result. The application improves the reliability of exhaust control.

Description

Technical Field

[0001] This invention relates to the field of exhaust control technology, and more specifically, to an exhaust control method and system for preventing cavitation in the suction pipe of an energy-saving water pump. Background Technology

[0002] In industrial production, municipal water affairs, agricultural irrigation and other fields, energy-saving water pumps have become important equipment in fluid transportation systems of various industries due to their advantages of efficient hydraulic design, intelligent control technology and low energy consumption. Energy-saving water pumps reduce hydraulic loss and mechanical wear through permanent magnet synchronous motor drive, variable frequency speed regulation and other technologies. However, this energy-saving advantage is restricted and damaged by the cavitation phenomenon of suction pipe. Cavitation has become an important factor affecting the efficient and stable operation of energy-saving water pumps.

[0003] Patent publication number CN112664464A discloses a smart and efficient optimization control method for water pumps. This method monitors the pressure, flow rate, and head parameters of the water pump in real time by setting pressure measuring points, differential pressure sensors, and flow meters in the inlet and outlet pipelines. It also constructs a dimensionless judgment criterion based on the net positive suction head (NPSH) model to constrain and control the pump inlet pressure. However, in practical applications, this method mainly judges and constrains cavitation based on the relationship between pressure parameters and NPSH, but it does not analyze and process the accumulation and precipitation of gas in the suction pipeline. Furthermore, this method focuses on monitoring and adjusting single-phase liquid flow parameters, lacking the identification and control of the gas-liquid two-phase state in the suction pipe. Secondly, cavitation has dynamic evolution characteristics, and this control method lacks the prediction and intervention of the cavitation formation state, making it difficult to suppress the entire cavitation process.

[0004] Therefore, it is necessary to design an exhaust control method and system for preventing cavitation in the suction pipe of an energy-saving water pump to solve the problems existing in the current technology. Summary of the Invention

[0005] In view of this, the present invention proposes an exhaust control method and system for preventing cavitation in the suction pipe of an energy-saving water pump, aiming to solve the above-mentioned problems.

[0006] In one aspect, the present invention proposes an exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump, comprising: The suction pipe of the energy-saving water pump is divided into segments based on the flow direction to determine several suction pipe segments. Pressure data, flow velocity data and gas detection data of each suction pipe segment are obtained. The data of each suction pipe segment are correlated and analyzed segment by segment based on the spatial order to determine the gas characteristic value of each suction pipe segment. The gas characteristic values ​​of adjacent suction pipe sections are calculated by difference and the direction of change is determined. Based on the change range of the gas characteristic value of the current suction pipe section relative to the previous suction pipe section, all suction pipe sections are divided. Suction pipe sections of the same type are merged to determine several gas sections. The positions of each gas section are compared, and the gas section that meets the gas characteristic value conditions and is located downstream of the water absorption direction is determined as the gas accumulation section. Based on the positional relationship between the gas accumulation section and the adjacent gas section, the corresponding exhaust pipe section is determined, and the exhaust valves of each exhaust pipe section are matched. Based on the gas characteristic value, each exhaust valve is sorted to determine the opening sequence of each exhaust valve. The opening sequence is compared with the historical database. Based on the number of occurrences of historical data in the historical database, it is determined whether the opening sequence should be adjusted. When it is determined that the opening sequence should be adjusted, the opening sequence is adjusted according to the number of occurrences of historical data. The adjusted opening sequence is verified based on the valve control model. The opening of each exhaust valve is controlled according to the verification results.

[0007] Furthermore, in determining the gas characteristic values ​​of each suction pipe segment, the process includes: numbering each suction pipe segment based on the flow direction of the suction pipe; determining the number of associated pressure data, flow velocity data, and gas detection data for each suction pipe segment based on an association rule algorithm, and determining the number of unassociated data; determining the association characteristic value based on the ratio of the associated number to the unassociated number; performing differential calculations on the pressure data, flow velocity data, and gas detection data of each suction pipe segment at the previous moment and the current moment to determine the pressure change value, flow velocity change value, and gas change value; normalizing the pressure change value, flow velocity change value, and gas change value; and performing a weighted calculation based on the normalization result and the association characteristic value to determine the gas characteristic value of each suction pipe segment.

[0008] Furthermore, when calculating the difference and determining the direction of change of the gas characteristic values ​​of adjacent suction pipe sections, the process includes: selecting the gas characteristic values ​​of the current suction pipe section and the previous suction pipe section sequentially based on the numbering order of each suction pipe section and calculating the difference between them. When the difference is positive, the direction of change of the gas characteristic value of the current suction pipe section is determined to be increasing. When the difference is negative, the direction of change of the gas characteristic value of the current suction pipe section is determined to be decreasing. When the difference is zero, the direction of change of the gas characteristic value of the current suction pipe section is determined to be stable.

[0009] Furthermore, in determining several gas sections, the process includes: dividing the suction pipe sections where the direction of change of all gas characteristic values ​​is increasing into increasing sections, dividing the suction pipe sections where the direction of change of all gas characteristic values ​​is decreasing into decreasing sections, and dividing the suction pipe sections where the direction of change of all gas characteristic values ​​is stable into stable sections. When there are consecutive suction pipe sections in the increasing / decreasing / stable sections, these consecutive suction pipe sections are merged to determine several gas sections. When there are no consecutive suction pipe sections in the increasing / decreasing / stable sections, and the direction of change of gas characteristic values ​​in adjacent suction pipe sections is increasing or decreasing, these adjacent suction pipe sections are merged to determine several gas sections.

[0010] Furthermore, when determining a gas accumulation segment, the process includes: acquiring the spatial location and corresponding gas characteristic value of each gas segment; sorting each gas segment based on the water absorption direction; if the gas characteristic value of the current gas segment is greater than that of its upstream gas segment, then the gas segment is marked as a candidate segment; and among the candidate segments, the gas segments with gas characteristic values ​​greater than the gas characteristic value threshold are determined as the gas accumulation segment.

[0011] Furthermore, in determining the opening sequence of each exhaust valve, the process includes: matching the exhaust valve with the gas section, sorting the exhaust valves based on the gas characteristic value, sorting the exhaust valves based on the distance between the exhaust valve and the gas accumulation section when there are identical gas characteristic values, prioritizing exhaust valves with a distance less than a distance threshold, and determining the opening sequence of each exhaust valve based on the sorting result.

[0012] Furthermore, when determining whether to adjust the opening sequence, the process includes: the historical database includes several historical opening sequences and the historical opening counts of corresponding exhaust valves; the opening sequence is traversed in the historical database; when there is an exhaust valve corresponding to a historical opening sequence that is the same as the exhaust valve in the opening sequence, the historical opening count of the corresponding exhaust valve is obtained; if the corresponding historical opening count is greater than or equal to a historical opening count threshold, it is determined that the opening sequence should be adjusted; if the corresponding historical opening count is less than the historical opening count threshold, or if there is no exhaust valve corresponding to a historical opening sequence that is the same as the exhaust valve in the opening sequence, it is determined that the opening sequence should not be adjusted.

[0013] Furthermore, when adjusting the opening sequence, the following steps are included: prioritizing exhaust valves whose historical opening count is greater than or equal to a historical opening count threshold in the opening sequence; when adjacent exhaust valves are all prioritized based on their historical opening count, the priority order is determined based on the numerical value of the corresponding historical opening count of the adjacent exhaust valves.

[0014] Furthermore, when verifying the adjusted opening sequence based on the valve control model, the process includes: taking the opening sequence and historical database as input, and outputting model results based on the valve control model. If the model results are consistent with the adjusted opening sequence, the verification is successful, and the opening of each exhaust valve is controlled according to the adjusted opening sequence. If the model results are inconsistent with the adjusted opening sequence, the verification fails, and the opening of each exhaust valve is controlled according to the model results.

[0015] Compared with existing technologies, the advantages of this invention are as follows: The suction pipe of the energy-saving water pump is segmented based on the flow direction, acquiring pressure, flow velocity, and gas detection data for each segment. Based on spatial order, the data of each suction pipe segment are correlated and analyzed segment by segment to determine gas characteristic values. This achieves quantitative characterization of the gas-liquid two-phase state of the suction pipe, overcoming the shortcomings of only monitoring single-phase liquid parameters and fully restoring the true state of gas evolution and distribution. By calculating the difference and determining the direction of change of gas characteristic values ​​of adjacent suction pipe segments, the evolution trend of gas along the water flow direction can be clearly identified. Furthermore, by comparing the positions of each gas segment to determine the gas accumulation segment, and by determining the opening sequence based on the gas characteristic values, the high-risk source of cavitation can be accurately located. Active intervention in gas accumulation from the source is achieved. The opening sequence is compared with the historical database, adjusted according to the frequency of occurrence in historical data, and verified by the valve control model, forming a complete closed-loop control link. This adapts to the dynamic evolution characteristics of cavitation and achieves intervention in the entire cavitation process, ensuring the stable operation of the energy-saving water pump.

[0016] On the other hand, this application also provides an exhaust control system for preventing cavitation in the suction pipe of an energy-saving water pump, for applying the above-mentioned exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump, including: The data acquisition unit is configured to divide the suction pipe of the energy-saving water pump into segments based on the flow direction, determine several suction pipe segments, acquire pressure data, flow velocity data and gas detection data of each suction pipe segment, and correlate and analyze the data of each suction pipe segment based on spatial order to determine the gas characteristic value of each suction pipe segment. The analysis unit is configured to calculate the difference and determine the direction of change of the gas characteristic values ​​of adjacent water intake pipe sections, and divide all water intake pipe sections based on the change range of the gas characteristic value of the current water intake pipe section relative to the previous water intake pipe section, and merge water intake pipe sections of the same type to determine several gas sections. The processing unit is configured to compare the positions of each gas segment, identify the gas segment that meets the gas characteristic value conditions and is located downstream of the water absorption direction as the gas accumulation segment, determine the corresponding exhaust pipe segment based on the positional relationship between the gas accumulation segment and the adjacent gas segment, match the exhaust valves of each exhaust pipe segment, sort each exhaust valve based on the gas characteristic value, and determine the opening sequence of each exhaust valve. The control unit is configured to compare the opening sequence with a historical database, determine whether to adjust the opening sequence based on the number of occurrences of historical data in the historical database, and when it is determined that the opening sequence should be adjusted, adjust the opening sequence according to the number of occurrences of historical data, verify the adjusted opening sequence based on the valve control model, and control the opening of each exhaust valve according to the verification result.

[0017] It is understandable that the above-mentioned exhaust control method and system for preventing cavitation in the suction pipe of energy-saving water pumps have the same beneficial effects, and will not be elaborated further here. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart of an exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump, provided as an embodiment of the present invention; Figure 2 This is a functional block diagram of an exhaust control system for preventing cavitation in the suction pipe of an energy-saving water pump, provided as an embodiment of the present invention. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] See Figure 1As shown in some embodiments of this application, an exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump includes: S100: Based on the flow direction, the suction pipe of the energy-saving water pump is divided into segments to determine several suction pipe segments. The pressure data, flow rate data and gas detection data of each suction pipe segment are obtained. Based on the spatial order, the data of each suction pipe segment are correlated and analyzed segment by segment to determine the gas characteristic value of each suction pipe segment. S200: Calculate the difference and determine the direction of change of the gas characteristic values ​​of adjacent water suction pipe sections, and divide all water suction pipe sections based on the change range of the gas characteristic value of the current water suction pipe section relative to the previous water suction pipe section, and merge water suction pipe sections of the same type to determine several gas sections. S300: The positions of each gas section are compared, and the gas section that meets the gas characteristic value conditions and is located downstream of the water absorption direction is identified as the gas accumulation section. Based on the positional relationship between the gas accumulation section and the adjacent gas section, the corresponding exhaust pipe section is determined, and the exhaust valves of each exhaust pipe section are matched. Based on the gas characteristic value, each exhaust valve is sorted to determine the opening sequence of each exhaust valve. S400: The opening sequence is compared with the historical database. Based on the number of occurrences of historical data in the historical database, it is determined whether the opening sequence should be adjusted. When it is determined that the opening sequence should be adjusted, the opening sequence is adjusted according to the number of occurrences of historical data, and the adjusted opening sequence is verified based on the valve control model. The opening of each exhaust valve is controlled according to the verification results.

[0023] Specifically, the flow direction is the direction of water flow from the front end of the suction pipe to the impeller of the pump. The suction pipe has the fluid dynamic characteristics of gradually decreasing pressure and dynamic changes in flow velocity. Dissolved gas in the water will continue to be released as the pressure decreases, forming bubbles and gradually accumulating. Moreover, gas release and accumulation only occur in local pipe sections rather than the entire pipe. Therefore, by dividing the continuous suction pipe into several independent suction pipe sections of uniform length and interconnected along the water flow direction, the spatial grid-like decomposition of gas distribution in the suction pipe is realized. This fundamentally solves the blind spot of being unable to identify the specific location of gas accumulation when monitoring the entire pipe as a whole. The number of divisions can be dynamically adjusted according to the length of the suction pipe. Based on Henry's Law, the lower the hydrostatic pressure of a liquid, the lower the solubility of dissolved gases in water, and the easier it is for free gas bubbles to precipitate, which is a significant factor inducing cavitation. After segmentation, pressure, flow velocity, and gas detection data were acquired for each suction pipe segment. The pressure data were the real-time pressure values ​​at each sampling moment. The flow velocity data included the average flow velocity, instantaneous flow velocity, and fluid Reynolds number for each suction pipe segment. The gas detection data included the free gas volume fraction (the proportion of free gas bubble volume to the total fluid volume), dissolved gas content, and total gas content for each suction pipe segment. The pressure, flow velocity, and gas detection data reconstructed the true state of the gas-liquid two-phase flow within the suction pipe from three dimensions: pressure inducing factors, flow velocity carriers, and gas itself, ensuring the reliability of venting from the energy-saving water pump's suction pipe. Based on spatial order, the data of each suction pipe segment are correlated and analyzed segment by segment. Spatial order refers to the order in which the water flows through each suction pipe segment. Pressure data, flow velocity data, and gas detection data are correlated accordingly. Then, the three types of data for each suction pipe segment are quantitatively analyzed segment by segment. Through data fusion calculation, the gas characteristic value of each suction pipe segment is determined. The gas characteristic value is a comprehensive quantitative index formed by integrating pressure, flow velocity, and gas detection data. It accurately reflects the gas accumulation tendency and cavitation induction situation in a single suction pipe segment. The difference of gas characteristic values ​​of adjacent suction pipe segments is calculated and the direction of change is determined. The difference calculation is to subtract the gas characteristic value of the previous suction pipe segment from the current gas characteristic value to determine the change range along the pipe. The direction of change determination clarifies whether the gas characteristic value is rising, falling, or remaining unchanged, thereby extracting the dynamic evolution trend of gas along the water flow direction and accurately locating the path of abnormal gas accumulation. Based on the variation of the gas characteristic value of the current suction pipe segment relative to the previous suction pipe segment, all suction pipe segments are divided. The suction pipe segments are classified according to the magnitude of the variation and the consistency of the variation trend. Then, continuous suction pipe segments of the same type are merged into gas segments. Scattered single pipe segment data are integrated into continuous path data, which simplifies the complexity of comprehensive analysis of pipeline gas distribution.By comparing the locations of each gas section, the gas section that meets the gas characteristic value conditions and is located downstream in the water suction direction is identified as the gas accumulation section. Since the gas density is much lower than that of the liquid, it will continue to move downstream in the water suction direction under the push of the water flow. Moreover, the downstream pipe section is closer to the water pump impeller and has lower pressure, which is also the area where gas is most likely to accumulate in large quantities. By combining the gas characteristic values, the high-risk area with the highest gas concentration and the greatest risk of cavitation in the water suction pipeline can be accurately located, so as to achieve targeted identification of the source of cavitation.

[0024] Understandably, gas accumulation zones are high-risk areas for cavitation, while adjacent gas zones are transitional areas for gas diffusion and migration. Gas will not remain stationary within the accumulation zone; it will diffuse and spread to adjacent zones along the water flow direction. The exhaust pipe sections are determined according to the principles of full coverage and extended anti-diffusion. The exhaust pipe sections are selected based on the high points, bends, and diameter changes of the water intake pipe (physical locations where gas tends to float and stagnate due to its low density) to avoid secondary gas accumulation. Since the installation location, specifications, and quantity of exhaust valves are adapted to the length, gas concentration, pipeline structure, and gas emission volume of the exhaust pipe sections, each exhaust pipe section has a corresponding valve to perform exhaust, ensuring that there are no dead zones in the exhaust process. Based on the gas characteristic values, each exhaust valve is sorted to determine the opening sequence of each exhaust valve. The exhaust pipe section with the higher the gas characteristic value has a larger gas accumulation and a more urgent risk of cavitation. The corresponding exhaust valve is opened first, thus forming a targeted control logic of prioritizing exhaust in high-risk areas and subsequent exhaust in low-risk areas. This proactively intervenes at the source of cavitation formation to prevent the continuous accumulation of gas from causing cavitation damage, avoiding the shortcomings of only passively constraining pressure and being unable to actively deal with gas accumulation. After determining the opening sequence of the exhaust valves, the sequence is compared with a historical database. This database stores complete historical data on the opening sequence of exhaust valves under different operating conditions, operating periods, and environmental conditions throughout the entire lifecycle of the energy-saving water pump. Because the operating conditions of the energy-saving water pump are repetitive, and the gas accumulation patterns and cavitation induction conditions in the pipeline also exhibit periodic characteristics, comparison with data-driven historical data ensures that valve control aligns with the actual operating patterns of the energy-saving water pump. The frequency of occurrence of historical data in the database determines whether the opening sequence needs adjustment. A higher frequency indicates a stronger suitability of the opening sequence for suppressing gas accumulation, preventing cavitation, and ensuring stable pump operation. If an adjustment is deemed necessary, the opening sequence is adjusted based on the frequency of occurrence of historical data. The valve opening priority is reordered based on the frequency of operation, prioritizing the high-frequency, high-reliability opening logic. This makes the venting control strategy more suitable for the long-term operating characteristics of the water pump, improving the stability and consistency of cavitation control. After adjustment, the adjusted opening sequence is verified based on the valve control model. The valve control model is a simulation verification model constructed by combining the fluid dynamics characteristics of the suction pipeline, the laws of gas movement and accumulation, historical venting data, and the cavitation induction and inhibition mechanism. It can accurately simulate the venting process, gas discharge efficiency, and pipeline pressure and flow rate recovery under different opening sequences, avoiding problems such as venting failure and cavitation recurrence caused by ineffective adjustments or incorrect sequences. The opening of each venting valve is controlled according to the verification results, thereby realizing intervention and active inhibition of the entire cavitation process, ensuring the accuracy and stability of venting control, and thus ensuring that the energy-saving water pump is in a high-efficiency and stable operating state.

[0025] In some embodiments of this application, determining the gas characteristic value of each suction pipe segment includes: numbering each suction pipe segment based on the flow direction of the suction pipe; determining the number of associated pressure data, flow velocity data, and gas detection data for each suction pipe segment based on an association rule algorithm, and determining the number of unassociated data; determining the association characteristic value based on the ratio of the number of associated data to the number of unassociated data; performing differential calculations on the pressure data, flow velocity data, and gas detection data of each suction pipe segment at the previous moment and the current moment to determine the pressure change value, flow velocity change value, and gas change value; normalizing the pressure change value, flow velocity change value, and gas change value; and performing a weighted calculation based on the normalization result and the association characteristic value to determine the gas characteristic value of each suction pipe segment.

[0026] Specifically, each suction pipe segment is assigned a unique number according to the order of water flow, establishing a fixed and unique identifier for each segment. This ensures that all subsequent data calculations and analyses are linked to the corresponding pipe segment. Since the pressure, flow velocity, and gas detection data within the suction pipe are not independent discrete parameters but rather exhibit fluid dynamic coupling, according to Henry's Law, a decrease in pressure directly leads to the precipitation of dissolved gases in the water and an increase in gas detection data. The precipitation and accumulation of gas, in turn, alters the fluid density and cross-sectional area within the pipe, resulting in fluctuations in flow velocity and increased pressure loss. The flow velocity directly determines whether bubbles are carried by the water flow and whether they remain and accumulate, further influencing pressure and gas levels. The distribution state of the three forms a dynamic coupling relationship, which cannot be described by humans through experience or fixed formulas. Secondly, the operating conditions of energy-saving water pumps are dynamic and variable. The association rule algorithm can mine the inherent fluid dynamic coupling relationship between pressure data, flow rate data, and gas detection data in a data-driven manner. Among them, the number of associated data is the number of data that match each other and have a stable correspondence among the three types of data, and the number of unassociated data is the number of data that are isolated from each other and have no coupling logic. The association feature value is determined based on the ratio of the number of associated data to the number of unassociated data. The association feature value can directly quantify the degree of association among the three types of data. The larger the ratio, the higher the coupling between the data. Differential calculations are performed on the pressure, flow velocity, and gas detection data of each suction pipe section at the previous and current moments. Specifically, differential calculations are performed on the pressure data, the instantaneous flow velocity in the flow velocity data, and the free gas volume fraction in the gas detection data to determine the pressure, flow velocity, and gas change values. Since these three values ​​belong to different physical dimensions, they cannot be directly merged. Normalization can unify these three types of changes with different dimensions and magnitudes. The values ​​are converted to dimensionless values ​​within the range of 0 to 1 to eliminate calculation biases caused by differences in dimensions and magnitudes, ensuring that the three types of change values ​​are calculated on an equal scale. Weighted calculations are then performed based on the normalized results and associated characteristic values. This involves determining the sum of the product of the associated characteristic value and its corresponding weight, and the product of each normalized change value and its corresponding weight. Statistical algorithms such as entropy weighting, Pearson correlation coefficient, and principal component analysis (PCA) are used to determine the weights of pressure, flow rate, and gas change values, or analytic hierarchy process (AHP) and expert scoring methods are used to determine the corresponding weights. Ultimately, gas characteristic values ​​that comprehensively reflect the gas content, gas accumulation rate, and cavitation risk level within a single suction pipe section are determined, laying the data foundation for subsequent gas segmentation.

[0027] In some embodiments of this application, when calculating the difference and determining the direction of change of the gas characteristic values ​​of adjacent suction pipe sections, the method includes: selecting the gas characteristic values ​​of the current suction pipe section and the previous suction pipe section in sequence based on the numbering order of each suction pipe section and calculating the difference between the two. When the difference is positive, the direction of change of the gas characteristic value of the current suction pipe section is determined to be increasing. When the difference is negative, the direction of change of the gas characteristic value of the current suction pipe section is determined to be decreasing. When the difference is zero, the direction of change of the gas characteristic value of the current suction pipe section is determined to be stable.

[0028] Specifically, based on the numbering order of each suction pipe segment, the gas characteristic values ​​of the current suction pipe segment and the previous suction pipe segment are selected sequentially, and the difference between the two is calculated. The static gas characteristic value of a single suction pipe segment is transformed into a quantitative indicator that can reflect the range of gas variation along the pipe. Since the precipitation and accumulation of gas in the suction pipe is a continuous and dynamic evolution process along the direction of water flow, the gas characteristic value of a single pipe segment can only characterize the instantaneous gas state of that pipe segment. Only by calculating the difference between adjacent pipe segments can the range of gas content, accumulation degree and cavitation risk along the pipe be accurately quantified, providing an objective data basis for judging the gas movement trend. Based on this, when the calculated difference is positive, the direction of change of the gas characteristic value of the current water intake pipe section is determined to be increasing, indicating that the risk of cavitation is gradually increasing. When the difference is negative, it indicates that the gas is effectively carried by the water flow and the degree of accumulation is reduced, and the risk of cavitation decreases accordingly. When the difference is zero, it indicates that the gas state of the current water intake pipe section is in dynamic equilibrium with that of the previous water intake pipe section. The accuracy of the selection of adjacent pipe sections is ensured by the numbering order, and the gas state description is transformed from static to dynamic quantification through difference calculation, thereby completing the identification of the gas evolution trend along the pipeline. This simplifies the analysis complexity of the gas state of the entire water intake pipeline and provides a trend basis for the subsequent division of gas sections.

[0029] In some embodiments of this application, determining several gas sections includes: dividing the suction pipe section where the direction of change of all gas characteristic values ​​is increasing into an increasing pipe section, dividing the suction pipe section where the direction of change of all gas characteristic values ​​is decreasing into a decreasing pipe section, and dividing the suction pipe section where the direction of change of all gas characteristic values ​​is stable into a stable pipe section. When there are consecutive suction pipe sections in the increasing / decreasing / stable pipe sections, the consecutive suction pipe sections are merged to determine several gas sections. When there are no consecutive suction pipe sections in the increasing / decreasing / stable pipe sections, and the direction of change of gas characteristic values ​​in adjacent suction pipe sections is increasing or decreasing, the adjacent suction pipe sections are merged to determine several gas sections.

[0030] Specifically, all suction pipe sections are precisely classified according to the direction of change in gas characteristic values. Suction pipe sections with increasing characteristics are classified as increasing sections, those with decreasing characteristics as decreasing sections, and those with stable characteristics as stable sections. Increasing sections indicate continuous gas precipitation and accumulation, with a rising risk of cavitation. Decreasing sections indicate gas diffusion carried by water flow, with a gradually decreasing risk of cavitation. Stable sections indicate a dynamic balance between gas content and accumulation. Classifying by direction of change ensures that each type of section possesses uniform gas properties. This classification aligns with the actual evolution of gas along the suction pipe. When increasing sections, decreasing sections, and stable sections exhibit a stable cavitation risk, the gas content and accumulation are in dynamic equilibrium. When there are continuous suction pipe sections in the reduced-flow and stable-flow pipe sections, the continuous suction pipe sections of the same type are merged. Since the accumulation, diffusion, and stabilization of gas in the suction pipeline do not occur in isolation in a single pipe section, but are continuously distributed along the direction of water flow, continuous pipe sections with the same trend belong to the same complete gas evolution process. If they are not merged, a large amount of scattered single-pipe section data will be retained, resulting in fragmented pipeline gas distribution analysis and making it impossible to identify continuous gas accumulation, diffusion, or stabilization areas. The continuous gas section formed after merging can truly restore the continuity characteristics of pipeline gas distribution, integrating scattered single pipe sections into continuous path-based units, and avoiding the judgment bias caused by fragmented data. When there are no continuous suction pipe sections in the ascending / decreasing / stable pipe segments—that is, no adjacent continuous suction pipe sections with the same change—but the gas characteristic values ​​of adjacent suction pipe sections change in the direction of ascending or decrementing segments (i.e., there is an upstream or downstream decrementing segment in the ascending pipe segment), these two types of adjacent suction pipe sections are merged. In discontinuous scenarios, adjacent ascending and decrementing pipe sections belong to the dynamic transition region from gas accumulation to diffusion, and there is a gas migration relationship between them in fluid dynamics. If the gas is divided separately, it will sever the complete evolution process from gas accumulation to diffusion and fail to reflect the true transition characteristics of gas state transformation. Merging the gas sections can completely preserve the regional attributes of gas dynamic transformation. By fully covering all water intake pipe sections, the division of gas sections is suitable for both conventional scenarios of continuous gas distribution and special scenarios of discontinuous gas transition. The resulting gas sections can completely and accurately reflect the gas distribution and evolution of the entire water intake pipe, improving the accuracy and comprehensiveness of cavitation source identification and targeted exhaust control.

[0031] In some embodiments of this application, when determining a gas accumulation segment, the process includes: obtaining the spatial location and corresponding gas characteristic value of each gas segment; sorting each gas segment based on the water absorption direction; if the gas characteristic value of the current gas segment is greater than that of its upstream gas segment, then marking the gas segment as a candidate segment; and determining the gas segment with a gas characteristic value greater than the gas characteristic value threshold among the candidate segments as a gas accumulation segment.

[0032] Specifically, the spatial location and corresponding gas characteristic values ​​of each gas segment are obtained. The spatial location clarifies the specific arrangement of each gas segment along the suction direction in the water intake pipeline, the upstream and downstream connection relationship, and the distance from the water pump impeller. The gas segments are sorted based on the suction direction, which is the direction of water flow from the water intake inlet to the water pump impeller. Since the density of gas is much lower than that of liquid, it will continuously migrate and accumulate along the suction direction under the influence of water flow and low pressure. This ensures the consistency between the sorting of gas segments and the actual migration path of the gas. If the gas characteristic value of the current gas segment is greater than that of its upstream gas segment, the gas segment is marked as a candidate segment. This is because the pressure in the water intake pipeline continuously decreases along the suction direction, and dissolved gas in the water will continuously precipitate. A gas characteristic value higher than that of the upstream segment indicates that the gas will continue to accumulate in the current segment and has a tendency to accumulate. Conversely, a gas characteristic value lower than or equal to that of the upstream segment indicates that the gas is diffused or in a stable state. By comparing the trends along the pipeline, segments with a tendency to accumulate are quickly screened out, improving the efficiency and accuracy of cavitation location and judgment. In the candidate sections, gas sections with gas characteristic values ​​greater than the gas characteristic value threshold are identified as gas accumulation sections. The gas characteristic value threshold is a judgment value pre-set by combining the anti-cavitation standard of energy-saving water pump, the hydraulic characteristics of the water intake pipeline, fluid medium parameters and cavitation induction conditions. The candidate sections only represent the existence of accumulation trend. By identifying high-risk areas with large gas accumulation and extremely high cavitation risk in the water intake pipeline, the source of cavitation is targeted and located. This provides a basis for determining the exhaust pipe section, matching the exhaust valve, and implementing targeted exhaust control, thereby improving the pertinence and reliability of anti-cavitation exhaust control.

[0033] In some embodiments of this application, determining the opening sequence of each exhaust valve includes: matching the exhaust valve with the gas section, sorting the exhaust valves based on gas characteristic values, sorting the exhaust valves based on the distance between the exhaust valve and the gas accumulation section when there are identical gas characteristic values, prioritizing exhaust valves with a distance less than a distance threshold, and determining the opening sequence of each exhaust valve based on the sorting result.

[0034] Specifically, exhaust valves are the actuators that perform exhaust actions on the corresponding exhaust pipe sections. Exhaust valves are ranked based on gas characteristic values, which quantify the gas content, accumulation intensity, and cavitation risk level within a given gas section. Higher gas characteristic values ​​indicate a greater urgency of cavitation induction within that gas section. By ranking exhaust valves according to their gas characteristic values, priority is given to venting the area with the highest cavitation risk, thereby quickly blocking the path of continuous gas accumulation that leads to cavitation. This prevents gas stagnation in high-risk areas and premature cavitation due to improper exhaust sequence. When gas characteristic values ​​are the same, exhaust valves are ranked based on their distance from the gas accumulation section, prioritizing those with a distance less than a threshold. Since identical gas characteristic values ​​imply consistent risk levels, the determining factor for exhaust efficiency becomes the spatial distance between the exhaust valve and the gas accumulation area. Closer distances indicate shorter exhaust paths, lower gas discharge resistance, and more direct exhaust effects on the accumulation area. Exhaust valves with distances less than this threshold are considered key valves covering the accumulation area. Gas valves must be opened first to quickly vent accumulated gas in the core area. Failure to prioritize them by distance will result in low venting efficiency at the same risk level, failing to quickly eliminate the source of cavitation. For example, the opening order might be vent valve 1, vent valve 2, and vent valve 3. However, gas segments 2 and 3 have the same gas characteristic values, but vent valve 3 is the closest to the gas accumulation segment. Therefore, according to the priority principle, the opening order should be vent valve 1, vent valve 3, and vent valve 2. Under the condition of identical gas characteristic values, spatial distance further optimizes the venting priority, improving the venting speed and venting effect on the gas accumulation segment. Finally, the opening order of each vent valve is determined based on the complete arrangement result. This sorting integrates the principles of prioritizing gas risk and enhancing spatial venting efficiency, conforming to the gas accumulation distribution pattern and fluid dynamics venting characteristics within the water intake pipeline. This achieves rapid targeted venting of gas accumulation segments and priority handling of high-risk areas, ensuring the energy-saving water pump operates in a highly efficient and stable state.

[0035] In some embodiments of this application, determining whether to adjust the opening sequence includes: a historical database containing several historical opening sequences and the historical opening counts of corresponding exhaust valves; traversing the historical database for the opening sequence; when there is an exhaust valve corresponding to a historical opening sequence that is the same as the exhaust valve in the opening sequence, obtaining the historical opening count of the corresponding exhaust valve; if the corresponding historical opening count is greater than or equal to a historical opening count threshold, determining that the opening sequence should be adjusted; if the corresponding historical opening count is less than the historical opening count threshold, or if there is no exhaust valve corresponding to a historical opening sequence that is the same as the exhaust valve in the opening sequence, determining that the opening sequence should not be adjusted.

[0036] Specifically, the historical opening sequence is the sequence of exhaust valve openings actually performed by the energy-saving water pump under different operating conditions, different gas accumulation scenarios, and different cavitation risk levels in the past. The historical opening count of the corresponding exhaust valve is the total frequency of each exhaust valve being opened during the historical anti-cavitation exhaust control process. The historical database stores the control experience accumulated over a long period of operation. The historical database can be accumulated and determined by experimental simulation, data simulation, and other methods. The currently generated opening sequence is iterated through the historical database, comparing each historical opening sequence with the one in the database. If the exhaust valve corresponding to a historical opening sequence is the same as the exhaust valve in the current opening sequence, the historical opening count of the corresponding exhaust valve is obtained. The historical opening count of the same exhaust valve can directly quantify the frequency of its activation in similar cavitation control scenarios in the past. The higher the historical opening count, the more times the control strategy of prioritizing the opening of the valve in the corresponding scenario has been run, and its cavitation exhaust efficiency is more reliable and has a stronger adaptability to hydraulic characteristics. Using the historical opening count threshold as the judgment standard, if the historical opening count of the corresponding exhaust valve is greater than or equal to the historical opening count threshold, it is determined that the opening sequence should be adjusted. After adjustment, the exhaust control logic can conform to the long-term operation pattern and avoid the deviation of the control strategy caused by real-time data fluctuations and sudden changes in instantaneous operating conditions. If the historical opening count of the corresponding exhaust valve is less than the historical opening count threshold, or if there is no exhaust valve in the historical opening sequence that is the same as the exhaust valve in the current opening sequence, then it is determined that the opening sequence will not be adjusted. The absence of the same valve indicates that the current operating condition and gas accumulation state are completely new scenarios, and there is no matching historical experience to reuse. In this case, retaining the real-time calculated opening sequence can adapt to the current unique operating state, avoiding problems such as exhaust failure and lagging cavitation control caused by blindly applying historical strategies. Based on historical data, a dual judgment mechanism of real-time strategy generation and historical experience verification is constructed. It not only ensures the comprehensiveness of historical data comparison through full domain traversal, but also avoids the failure of control strategy caused by relying solely on real-time calculation. Through data-driven approach, it ensures that the adjustment of the opening sequence can conform to the actual operating rules of the energy-saving water pump suction pipeline, improving the reliability of the exhaust control strategy and the accuracy of cavitation control.

[0037] In some embodiments of this application, adjusting the opening sequence includes: prioritizing exhaust valves whose historical opening count is greater than or equal to a historical opening count threshold in the opening sequence; when adjacent exhaust valves are all prioritized based on their historical opening count, the priority order is determined based on the numerical value of the historical opening count corresponding to the adjacent exhaust valves.

[0038] Specifically, exhaust valves with a historical opening count greater than or equal to the historical opening count threshold are prioritized in the opening sequence. These valves are frequently used in the actual operation of the energy-saving water pump's long-term anti-cavitation exhaust control, and their exhaust efficiency is relatively reliable. They are also compatible with the hydraulic characteristics and gas accumulation patterns of the suction pipeline. The opening logic of these valves has been tested in practice under various operating conditions, effectively avoiding the randomness and bias caused by factors such as instantaneous data fluctuations, sudden changes in operating conditions, and sensor errors in the real-time calculated opening sequence. Therefore, they are prioritized. For example, if the opening sequence is exhaust valve 1, exhaust valve 2, and exhaust valve 3, and exhaust valve 2 is an exhaust valve with a historical opening count greater than or equal to the historical opening count threshold, then according to the priority principle, the opening sequence is exhaust valve 2, exhaust valve 1, and exhaust valve 3. This quickly eliminates the cavitation risk caused by gas accumulation, improves the stability and reliability of the exhaust control strategy, and ensures that the exhaust action conforms to the long-term operation pattern of the water pump, avoiding exhaust failure and cavitation control lag caused by real-time strategy deviation. When adjacent exhaust valves are prioritized based on their historical opening counts, the priority order is determined by the numerical value of the corresponding historical opening counts for each adjacent exhaust valve. For example, if the opening order is exhaust valve 1, exhaust valve 2, and exhaust valve 3, and exhaust valves 1 and 2 are both prioritized based on their historical opening counts, then the numerical values ​​of the corresponding historical opening counts are compared. If the historical opening count for exhaust valve 1 is greater than or equal to that for exhaust valve 2, the sorting order remains exhaust valve 1, exhaust valve 2, and exhaust valve 3. If the historical opening count for exhaust valve 1 is less than that for exhaust valve 2, the sorting order is exhaust valve 2, exhaust valve 1, and exhaust valve 3. Since adjacent... All of these exhaust valves meet historical high reliability requirements. The number of historical openings can further quantify the valve's verification frequency and actual control performance. The larger the value, the higher the frequency of activation of the exhaust valve in similar cavitation risk scenarios, the stronger its adaptability, and the better its exhaust effect and cavitation suppression success rate. Sorting by value can accurately solve the sorting conflict problem of valves with the same priority, and prevent exhaust logic disorder and reduced exhaust efficiency caused by disordered sorting. It realizes a refined secondary sorting of valves, which conforms to the actual fluid dynamics law of gas accumulation and distribution in water intake pipeline and exhaust control. Thus, an adjusted opening sequence is formed that combines the reliability of historical experience with the accuracy of sorting, improving the targeting of exhaust control and the reliability of cavitation prevention and control.

[0039] In some embodiments of this application, when verifying the adjusted opening sequence based on the valve control model, the process includes: taking the opening sequence and historical database as input, and outputting model results based on the valve control model. When the model results are consistent with the adjusted opening sequence, the verification is successful, and the opening of each exhaust valve is controlled according to the adjusted opening sequence. When the model results are inconsistent with the adjusted opening sequence, the verification fails, and the opening of each exhaust valve is controlled according to the model results.

[0040] Specifically, the valve control model is a simulation verification model pre-built based on the fluid dynamics characteristics of the energy-saving water pump's suction pipeline, gas evolution and accumulation patterns, cavitation induction and inhibition mechanisms, full historical exhaust control data, and exhaust effect parameters under different operating conditions. It possesses the ability to simulate the exhaust process of the suction pipeline, evaluate exhaust efficiency, predict exhaust control effects, and verify the opening sequence. The valve control model can be trained and determined using convolutional neural network models, random forests, and other related machine learning models. Inputting the opening sequence into the model allows it to perform a full-dimensional simulation of the exhaust effect, cavitation inhibition capability, and pipeline operational stability of that sequence. Inputting the historical database into the model ensures that it relies on long-term accumulated real-world operating experience and control logic as a decision-making benchmark, guaranteeing the reliability of the verification results. The valve control model outputs model results based on learned data patterns and models. The model results are the exhaust valve opening sequence calculated by the valve control model based on the current pipeline status, historical operating patterns, and cavitation control requirements. This sequence can accurately adapt to the current real-time operating conditions and gas accumulation state, and the adjusted opening sequence can be corrected accordingly. The model may have issues such as over-reliance on historical experience and insufficient adaptation to instantaneous operating conditions. When the model results are consistent with the adjusted opening sequence, it indicates that the adjusted opening sequence meets both the reliability requirements of historical operating experience and the standards of model simulation. In this case, directly controlling the opening of each exhaust valve according to the adjusted opening sequence can ensure the accuracy and stability of exhaust control. When the model results are inconsistent with the adjusted opening sequence, it indicates that the adjusted opening sequence is not compatible with the current real-time operating conditions, pipeline gas state, and cavitation control requirements. Direct execution may lead to reduced exhaust efficiency, delayed cavitation control, or even exhaust failure. The model results output by the valve control model are strategies that have been verified through full-dimensional simulation and are more in line with the current actual operating state. Therefore, controlling the opening of each exhaust valve according to the model results can avoid the limitations and potential risks of the adjusted opening sequence. It not only ensures the practical basis for verification through the historical database but also realizes intelligent verification and optimization of the opening sequence through model simulation, thereby improving the accuracy and reliability of exhaust control and achieving precise suppression of cavitation throughout the entire process.

[0041] It should be noted that the valve control model in this application can preferably be implemented using existing technologies in the field, and it is not the focus of the improvement claimed in this application. The focus of the improvement in this application lies in its data organization method, data connection relationship, and constraint processing logic for handling the opening sequence and historical database. The valve control model takes the opening sequence and historical database as input and outputs model results. Those skilled in the art can complete the adaptation, replacement, or equivalent implementation based on the input-output relationship, parameter configuration rules, and calling sequence disclosed in this application, combined with existing disclosed technologies or conventional engineering methods, without affecting the implementation of the technical solution of this application.

[0042] In summary, the beneficial effects of this invention are as follows: The suction pipe of the energy-saving water pump is segmented based on the flow direction, acquiring pressure, flow velocity, and gas detection data for each segment. Based on spatial order, the data of each suction pipe segment are correlated and analyzed segment by segment to determine gas characteristic values. This achieves quantitative characterization of the gas-liquid two-phase state of the suction pipe, overcoming the shortcomings of only monitoring single-phase liquid parameters and fully restoring the true state of gas evolution and distribution. By calculating the difference and determining the direction of change of gas characteristic values ​​of adjacent suction pipe segments, the evolution trend of gas along the water flow direction can be clearly identified. Furthermore, by comparing the positions of each gas segment to determine the gas accumulation segment, and by determining the opening sequence based on the gas characteristic values, the high-risk source of cavitation can be accurately located. Active intervention in gas accumulation from the source is achieved. The opening sequence is compared in a historical database, adjusted according to the frequency of occurrence in historical data, and verified by a valve control model, forming a complete closed-loop control link. This adapts to the dynamic evolution characteristics of cavitation and achieves intervention in the entire cavitation process, ensuring the stable operation of the energy-saving water pump.

[0043] In another preferred embodiment based on the above embodiments, see [reference] Figure 2 As shown, this embodiment provides an exhaust control system for preventing cavitation in the suction pipe of an energy-saving water pump, which applies the above-described exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump, including: The data acquisition unit is configured to divide the suction pipe of the energy-saving water pump into segments based on the flow direction, determine several suction pipe segments, acquire pressure data, flow velocity data and gas detection data of each suction pipe segment, and correlate and analyze the data of each suction pipe segment based on spatial order to determine the gas characteristic value of each suction pipe segment. The analysis unit is configured to calculate the difference and determine the direction of change of the gas characteristic values ​​of adjacent water intake pipe sections, and divide all water intake pipe sections based on the change range of the gas characteristic value of the current water intake pipe section relative to the previous water intake pipe section, and merge water intake pipe sections of the same type to determine several gas sections. The processing unit is configured to compare the positions of each gas section, identify the gas section that meets the gas characteristic value conditions and is located downstream of the water absorption direction as the gas accumulation section, determine the corresponding exhaust pipe section based on the positional relationship between the gas accumulation section and the adjacent gas section, match the exhaust valves of each exhaust pipe section, sort each exhaust valve based on the gas characteristic value, and determine the opening sequence of each exhaust valve. The control unit is configured to compare the opening sequence with the historical database, determine whether to adjust the opening sequence based on the number of occurrences of historical data in the historical database, and when it is determined that the opening sequence should be adjusted, the opening sequence is adjusted according to the number of occurrences of historical data, and the adjusted opening sequence is verified based on the valve control model. The opening of each exhaust valve is controlled according to the verification result.

[0044] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program goods according to embodiments of this application. 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... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0045] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that modifications or equivalent substitutions can still be made to the specific implementation of the present invention. Any modifications or equivalent substitutions that do not depart from the spirit and scope of the present invention should be covered within the scope of protection of the claims of the present invention.

Claims

1. A method for controlling venting to prevent cavitation in the suction pipe of an energy-saving water pump, characterized in that, include: The suction pipe of the energy-saving water pump is divided into segments based on the flow direction to determine several suction pipe segments. Pressure data, flow velocity data and gas detection data of each suction pipe segment are obtained. The data of each suction pipe segment are correlated and analyzed segment by segment based on the spatial order to determine the gas characteristic value of each suction pipe segment. The gas characteristic values ​​of adjacent suction pipe sections are calculated by difference and the direction of change is determined. Based on the change range of the gas characteristic value of the current suction pipe section relative to the previous suction pipe section, all suction pipe sections are divided. Suction pipe sections of the same type are merged to determine several gas sections. The positions of each gas section are compared, and the gas section that meets the gas characteristic value conditions and is located downstream of the water absorption direction is determined as the gas accumulation section. Based on the positional relationship between the gas accumulation section and the adjacent gas section, the corresponding exhaust pipe section is determined, and the exhaust valves of each exhaust pipe section are matched. Based on the gas characteristic value, each exhaust valve is sorted to determine the opening sequence of each exhaust valve. The opening sequence is compared with the historical database. Based on the number of occurrences of historical data in the historical database, it is determined whether the opening sequence should be adjusted. When it is determined that the opening sequence should be adjusted, the opening sequence is adjusted according to the number of occurrences of historical data. The adjusted opening sequence is verified based on the valve control model. The opening of each exhaust valve is controlled according to the verification results.

2. The exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump according to claim 1, characterized in that, The process of determining the gas characteristic values ​​of each suction pipe segment includes: numbering each suction pipe segment based on the flow direction of the suction pipe; determining the number of associated pressure data, flow velocity data, and gas detection data for each suction pipe segment based on an association rule algorithm, and determining the number of unassociated data; determining the association characteristic value based on the ratio of the associated number to the unassociated number; performing differential calculations on the pressure data, flow velocity data, and gas detection data of each suction pipe segment at the previous moment and the current moment to determine the pressure change value, flow velocity change value, and gas change value; normalizing the pressure change value, flow velocity change value, and gas change value; and performing a weighted calculation based on the normalization result and the association characteristic value to determine the gas characteristic value of each suction pipe segment.

3. The exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump according to claim 2, characterized in that, When calculating the difference and determining the direction of change of gas characteristic values ​​of adjacent suction pipe sections, the process includes: selecting the gas characteristic values ​​of the current suction pipe section and the previous suction pipe section in sequence according to the numbering order of each suction pipe section and calculating the difference between the two. When the difference is positive, the direction of change of the gas characteristic value of the current suction pipe section is determined to be increasing. When the difference is negative, the direction of change of the gas characteristic value of the current suction pipe section is determined to be decreasing. When the difference is zero, the direction of change of the gas characteristic value of the current suction pipe section is determined to be stable.

4. The exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump according to claim 3, characterized in that, When determining several gas sections, the process includes: dividing the suction pipe sections where the direction of change of all gas characteristic values ​​is increasing into increasing sections, dividing the suction pipe sections where the direction of change of all gas characteristic values ​​is decreasing into decreasing sections, and dividing the suction pipe sections where the direction of change of all gas characteristic values ​​is stable into stable sections. When there are consecutive suction pipe sections in the increasing / decreasing / stable sections, the consecutive suction pipe sections are merged to determine several gas sections. When there are no consecutive suction pipe sections in the increasing / decreasing / stable sections, and the direction of change of gas characteristic values ​​in adjacent suction pipe sections is increasing or decreasing, the adjacent suction pipe sections are merged to determine several gas sections.

5. The exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump according to claim 4, characterized in that, When identifying a gas accumulation zone, the process includes: obtaining the spatial location and corresponding gas characteristic value of each gas zone; sorting each gas zone based on the water absorption direction; if the gas characteristic value of the current gas zone is greater than that of its upstream gas zone, then marking the gas zone as a candidate zone; and identifying the gas zones with gas characteristic values ​​greater than the gas characteristic value threshold among the candidate zones as the gas accumulation zone.

6. The exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump according to claim 5, characterized in that, Determining the opening sequence of each exhaust valve includes: matching the exhaust valve with the gas section, sorting the exhaust valves based on the gas characteristic value, sorting the exhaust valves based on the distance between the exhaust valve and the gas accumulation section when there are identical gas characteristic values, prioritizing exhaust valves with a distance less than a distance threshold, and determining the opening sequence of each exhaust valve based on the sorting result.

7. The exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump according to claim 6, characterized in that, When determining whether to adjust the opening sequence, the process includes: the historical database includes several historical opening sequences and the historical opening counts of corresponding exhaust valves; the opening sequence is traversed in the historical database; when there is an exhaust valve corresponding to a historical opening sequence that is the same as the exhaust valve in the opening sequence, the historical opening count of the corresponding exhaust valve is obtained; if the corresponding historical opening count is greater than or equal to a historical opening count threshold, it is determined that the opening sequence should be adjusted; if the corresponding historical opening count is less than the historical opening count threshold, or if there is no exhaust valve corresponding to a historical opening sequence that is the same as the exhaust valve in the opening sequence, it is determined that the opening sequence should not be adjusted.

8. The exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump according to claim 7, characterized in that, When adjusting the opening sequence, the following steps are included: prioritizing exhaust valves whose historical opening count is greater than or equal to a historical opening count threshold in the opening sequence; when adjacent exhaust valves are all prioritized based on their historical opening count, the priority order is determined based on the numerical value of the historical opening count corresponding to the adjacent exhaust valves.

9. The exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump according to claim 8, characterized in that, When verifying the adjusted opening sequence based on the valve control model, the process includes: taking the opening sequence and historical database as input, and outputting model results based on the valve control model. If the model results are consistent with the adjusted opening sequence, the verification is successful, and the opening of each exhaust valve is controlled according to the adjusted opening sequence. If the model results are inconsistent with the adjusted opening sequence, the verification fails, and the opening of each exhaust valve is controlled according to the model results.

10. An exhaust control system for preventing cavitation in the suction pipe of an energy-saving water pump, used in applying the exhaust control method for preventing cavitation in the suction pipe of an energy-saving water pump as described in any one of claims 1-9, characterized in that, include: The data acquisition unit is configured to divide the suction pipe of the energy-saving water pump into segments based on the flow direction, determine several suction pipe segments, acquire pressure data, flow velocity data and gas detection data of each suction pipe segment, and correlate and analyze the data of each suction pipe segment based on spatial order to determine the gas characteristic value of each suction pipe segment. The analysis unit is configured to calculate the difference and determine the direction of change of the gas characteristic values ​​of adjacent water intake pipe sections, and divide all water intake pipe sections based on the change range of the gas characteristic value of the current water intake pipe section relative to the previous water intake pipe section, and merge water intake pipe sections of the same type to determine several gas sections. The processing unit is configured to compare the positions of each gas segment, identify the gas segment that meets the gas characteristic value conditions and is located downstream of the water absorption direction as the gas accumulation segment, determine the corresponding exhaust pipe segment based on the positional relationship between the gas accumulation segment and the adjacent gas segment, match the exhaust valves of each exhaust pipe segment, sort each exhaust valve based on the gas characteristic value, and determine the opening sequence of each exhaust valve. The control unit is configured to compare the opening sequence with a historical database, determine whether to adjust the opening sequence based on the number of occurrences of historical data in the historical database, and when it is determined that the opening sequence should be adjusted, adjust the opening sequence according to the number of occurrences of historical data, verify the adjusted opening sequence based on the valve control model, and control the opening of each exhaust valve according to the verification result.

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