Method and device for judging heat management state in start-stop process of heat absorber

Abstract

The invention relates to the technical field of heat absorber control, in particular to a heat absorber start-stop process heat management state judgment method and device, and the method comprises the steps: collecting the distributed temperature, low-point acoustics and temperature and meteorological data of a tube panel; carrying out three-dimensional reconstruction on the distributed temperature, generating a thermodynamic cloud picture, segmenting abnormity, calculating a comprehensive index of spatial thermal imbalance, and quantifying a thermodynamic balance level; fusing the meteorological data and the balance level, constructing a multi-dimensional information fused working condition conversion pre-judgment model, outputting a working condition conversion coefficient, and judging whether to turn into a salt dredging state or not; low-point acoustic frequency band energy is extracted in the salt dredging state, the synchronism of flow energy attenuation and cooling rate turning is detected in combination with a pipe wall cooling rate curve, and the local salt dredging state is judged; and establishing a thermal health state matrix, and uniformly mapping the thermal equilibrium level and each low-point salt dredging mark. According to the technical scheme, the controllability and stability of heat health of the heat absorber are improved, starting and stopping safety and efficiency are guaranteed, and the service life is prolonged.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of heat absorber control, in particular to a heat management state determination method and device for heat absorber start-stop process. BACKGROUND

[0002] The heat absorber bears the key functions of heat collection, transmission and heat exchange in solar heat utilization and high-temperature heat transfer systems, and its start-stop process involves frequent switching between operation and salt flushing conditions.

[0003] In existing heat absorber engineering practice, the heat management state determination in the start-stop process generally relies on dispersed measurement point information and single-dimensional monitoring quantities, which is difficult to form a synchronous characterization of the temperature distribution in the tube screen space, the local flow characteristics of the low point of the pipeline and the external meteorological changes. The direct result caused thereby is that there is a lack of a unified quantitative determination system that can run through the whole process of operation and salt flushing, which cannot give executable prediction basis before the working condition conversion, cannot consistently confirm and record the local completion during the salt flushing stage, further makes it difficult to realize the state comparison and historical tracing between different tube screens and different topological positions, and affects the safety, consistency and controllability of the start-stop.

[0004] In view of this, the application provides a heat management state determination method and device for heat absorber start-stop process SUMMARY To achieve the above-mentioned purpose, the application provides a heat management state determination method and device for heat absorber start-stop process, and the specific technical solutions are as follows: The heat management state determination method for heat absorber start-stop process comprises the following steps: Distributed temperature data of the heat absorber tube screen are collected by a temperature sensor, acoustic data and low point temperature data of the low point of the heat absorber pipeline are collected, and meteorological data of the environment to which the heat absorber belongs are obtained, so as to form synchronous data streams of spatial thermal force, local fluid dynamics and meteorological changes; In the operation state of the heat absorber, the distributed temperature data of the heat absorber are three-dimensionally reconstructed and time-sequentially registered to generate a real-time thermal force cloud picture, a temperature abnormal area is segmented and identified, a comprehensive index representing the degree of spatial thermal force imbalance is calculated, and a thermal engineering uniformity level is quantitatively standardized; The meteorological data and the thermal engineering uniformity level are fused to construct a working condition conversion prediction model based on multi-dimensional information fusion, a working condition conversion coefficient is output, whether a working condition conversion instruction is issued is determined according to the working condition conversion coefficient, and whether the heat absorber enters a salt flushing state from an operation state is controlled; In the salt flushing state of the heat absorber, acoustic signals of each low point of the heat absorber during salt flushing are obtained and frequency band energy is extracted, a cooling rate curve of the tube wall temperature is recorded, synchronous characteristics of flow energy attenuation and cooling rate turning are detected, and whether local salt flushing of the corresponding monitoring point is completed is determined; A heat absorber thermal health state matrix is established, the heat balance level of the heat absorber is uniformly mapped with each low point salt dissolving completion marker, indexed according to the tube panel number and pipeline topology, and updated in real time and traced back in history.

[0005] Preferably, distributed temperature data is collected on the surface of the heat absorber tube panel; acoustic sensors and temperature sensors are deployed at the low point of the heat absorber pipeline, and low point acoustic data and low point temperature data are collected synchronously; a solar tracker and an anemometer are provided on the heat absorber field area weather monitoring station to obtain the solar elevation angle and the wind speed change rate, respectively.

[0006] Preferably, in the operating state of the heat absorber, the collected distributed temperature data is reconstructed in three-dimensional space, a three-dimensional coordinate system is established and the sensor positions are mapped, a radial basis function interpolation is used to construct a continuous temperature field distribution function, and time series registration is performed to eliminate time deviation; A real-time thermal cloud image is generated based on the registered temperature field data, and the temperature distribution is visually projected and color-mapped by volume rendering technology; An edge detection algorithm based on gradient is used in combination with a statistical threshold judgment method to segment and identify temperature abnormal regions, calculate the spatial gradient of the temperature field, and determine whether the temperature of the local region exceeds the normal range.

[0007] Preferably, a comprehensive evaluation index system is constructed to quantify the spatial thermal imbalance degree, including: calculating the spatial non-uniformity coefficient of temperature distribution, the kurtosis value of temperature gradient distribution, and the proportion of abnormal regions; The spatial non-uniformity coefficient, the kurtosis value, and the proportion of abnormal regions are fused by weighting to form a spatial thermal imbalance comprehensive index, and the thermal balance standard is quantitatively divided into multiple grades according to the spatial thermal imbalance comprehensive index.

[0008] Preferably, the collected meteorological data is preprocessed and feature extracted, the solar elevation angle change rate and the wind speed change rate data are smoothed by sliding window processing, and a meteorological stability index is defined; The thermal balance level is numerically mapped, and the time derivative of the thermal balance is introduced to represent the dynamic change trend of the thermal state; A fusion decision function is established to fuse the meteorological stability index, the thermal balance, and the dynamic change trend of the thermal state, and a working condition conversion coefficient is defined.

[0009] Preferably, an adaptive learning mechanism of historical operation data is introduced, a historical working condition conversion event database is established, and a Bayesian updating method is used to dynamically adjust the weight parameters of the working condition conversion coefficient; A judgment threshold for working condition conversion is set, and the judgment threshold for working condition conversion is determined by the risk-reward balance principle; When the operating condition conversion coefficient exceeds the operating condition conversion determination threshold, it is determined that operating condition conversion is needed, and an operating condition conversion control instruction is generated to control the heat absorber to enter the salt-bleeding state from the running state.

[0010] Preferably, when the heat absorber enters the salt-bleeding state, the acoustic signals at each low point position are continuously collected and analyzed in real time. The short-time Fourier transform method is used for time-frequency analysis, and the signal is divided into multiple characteristic frequency bands for frequency band energy extraction to identify different stages of the salt-bleeding process. The pipe wall temperature data is obtained, and the instantaneous cooling rate curve is constructed and calculated. The five-point difference method is used for numerical differentiation, and the cooling rate curve is segmented and fitted to identify the salt-bleeding rate turning point.

[0011] Preferably, an acoustic energy attenuation and cooling rate turning point correlation analysis model 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 determination criterion for the completion of salt-bleeding of the heat absorber is constructed, which 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-bleeding completion confirmation mechanism is constructed, and the salt-bleeding completion state is divided into multiple levels.

[0012] Preferably, a heat health state matrix of the heat absorber is constructed, and a multi-dimensional matrix structure is used to store comprehensive state information including the heat balance level value and the salt-bleeding completion flag. A mapping relationship between the tube panel number and the physical position is established, and an adjacency relationship matrix is constructed according to the pipeline topology structure. A unified mapping mechanism for the heat balance level and the salt-bleeding completion flag is implemented, and a comprehensive health degree index is defined. A real-time updating mechanism is established to reflect the latest operating conditions of the heat absorber, and a historical data tracing mechanism is constructed.

[0013] The heat management state determination device for the heat absorber start-stop process is realized based on the heat management state determination method for the heat absorber start-stop process, and includes a data acquisition module, a heat balance evaluation module, a state conversion module, a shutdown detection module, and a management and maintenance module. The data acquisition module acquires distributed temperature data of the heat absorber tube panel through a temperature sensor, acquires acoustic data and low point temperature data of the heat absorber pipeline low point, and acquires meteorological data of the environment to which the heat absorber belongs, forming synchronous data streams of spatial thermal force, local fluid dynamics, and meteorological changes. The heat balance evaluation module performs three-dimensional reconstruction and time series registration on the distributed temperature data of the heat absorber in the running state to generate a real-time thermal force cloud map, identifies and segments the temperature abnormal area, calculates the comprehensive index representing the degree of spatial thermal imbalance, and quantifies the heat balance level. The state conversion module fuses meteorological data and thermal equilibrium level to build a working condition conversion prediction model based on multi-dimensional information fusion, outputs a working condition conversion coefficient, determines whether to issue a working condition conversion instruction according to the working condition conversion coefficient, and controls whether the heat absorber enters the salt-bleeding state from the running state; The shutdown detection module acquires acoustic signals of each low point of the heat absorber during salt bleeding and extracts frequency band energy, and records the cooling rate curve of the tube wall temperature, detects the synchronization characteristics of flow energy attenuation and cooling rate turning point, and determines whether the local salt bleeding of the corresponding monitoring point is completed; The management and maintenance module establishes a heat health state matrix of the heat absorber, uniformly maps the thermal equilibrium level of the heat absorber and the salt-bleeding completion flag, indexes according to the tube panel number and pipeline topology, and performs real-time updating and historical tracing.

[0014] The application has the beneficial effects that the application constructs a synchronous data stream covering space heat, pipeline low point fluid dynamics and external weather, provides a multi-source information basis consistent in time and space for subsequent determination, reduces the misjudgment risk caused by a single measurement dimension, improves data integrity and comparability, and supports the continuity and accuracy of the whole process monitoring.

[0015] The application realizes intuitive visualization and accurate positioning of the temperature field through three-dimensional reconstruction and time sequence registration, quantifies the spatial imbalance degree and forms a standardized level, facilitates cross-device and cross-period comparison, identifies abnormal areas in a timely manner, supports early intervention and operation strategy adjustment, and improves the efficiency of thermal equilibrium management.

[0016] The application fuses meteorological and thermal levels to build a prediction model and outputs an operable working condition conversion coefficient, realizes the transition from experience-based decision-making to data-driven, provides quantitative judgment basis before start-stop criticality, reduces the risk of unnecessary switching or delayed switching, and improves the safety and consistency of start-stop.

[0017] The application uses the synchronization characteristics of acoustic frequency band energy and cooling rate curve to realize the phased identification and completion determination of salt bleeding process, avoids the deviation caused by relying on a single signal, can finely confirm the completion of salt bleeding at local monitoring points, and helps to shorten the invalid salt bleeding time and reduce energy consumption.

[0018] The application uniformly maps the thermal level and the salt-bleeding flag through the heat health state matrix, realizes the structured and traceable management of the state in combination with the topology and number index, supports real-time updating and historical comparison, provides a quantitative health degree index for operation and maintenance, and facilitates partition control and strategy optimization closed loop. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 A heat management state determination method flowchart for the start-stop process of the heat absorber is provided in the application. Figure 2 The running state thermal balance evaluation flowchart provided for the present application is shown in FIG. 1. Figure 3 The working condition conversion pre-judgment and instruction issuing flowchart provided for the present application is shown in FIG. 2. Figure 4 The salt-removing state local salt-removing completion judgment flowchart provided for the present application is shown in FIG. 3. Figure 5 The heat absorber start-stop process thermal management state judgment device structure diagram provided for the present application is shown in FIG. 4. DETAILED DESCRIPTION

[0020] In order to make the above objectives, features and advantages of the present application more apparent and easy to understand, the specific embodiments of the present application will be described in detail below with reference to the accompanying drawings.

[0021] In the following description, a large number of specific details are set forth in order to facilitate a thorough understanding of the present application, but the present application can also be implemented in other ways different from the description, and those skilled in the art can make similar generalizations without departing from the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0022] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor does it mean an embodiment that is separate or selectively excluded from other embodiments.

[0023] Embodiment 1 Reference Figures 1 to 4 For the first embodiment of the present application, as shown in FIG. 1, a heat absorber start-stop process thermal management state judgment method is provided. Figure 1

[0024] Step 1: Collect distributed temperature data of the heat absorber tube screen through temperature sensors, and collect acoustic data and low point temperature data of the heat absorber tube low point, and obtain meteorological data of the environment to which the heat absorber belongs, to form a synchronous data stream of space thermal, local fluid dynamics and meteorological changes.

[0025] During the heat absorber start-stop process, a complete multi-source data acquisition system needs to be established first. A distributed temperature sensor array is installed on the surface of the heat absorber tube screen according to a preset grid layout. The sensor uses a K-type thermocouple, with a temperature measurement range of -200°C to 1350°C, meeting the temperature monitoring requirements of the heat absorber under all working conditions. The heat absorber tube screen is a direct device for receiving reflected sunlight. Each sensor is uniformly arranged to form a uniform monitoring network. For example, the temperature sensor acquisition frequency of the heat absorber tube screen surface can be set to 0.1 Hz to ensure that the dynamic change characteristics of the temperature field can be captured.​

[0026] For temperature and sound monitoring of the low point of the heat sink pipeline, the low point of the heat sink pipeline refers to the lowest position area of the heat sink pipeline system where the molten salt or other working medium is prone to accumulate due to gravity, usually located at the bottom of the U-shaped bend pipe, the connection between the horizontal pipe section and the vertical pipe section, and the bottom of the header. Acoustic sensors and temperature sensors are simultaneously deployed at these key low point positions; the acoustic sensor can use a piezoelectric acceleration sensor with a frequency response range of 10 Hz to 10 kHz, which can effectively capture the turbulent flow noise and bubble breaking sound generated by the molten salt flow; the acoustic sensor can be fixed on the outer surface of the pipe wall by magnetic attraction or strip rolling, and coated with high-temperature coupling agent to ensure effective transmission of acoustic signals.

[0027] The low point temperature sensor can use a patch type platinum resistance thermometer, which is directly attached to the outer surface of the pipe wall and filled with heat-conducting silicone grease, and is externally coated with thermal insulation material to reduce environmental interference. Temperature data and acoustic data are synchronously collected by the same clock reference to ensure the timing consistency of subsequent multi-source data fusion analysis. The acoustic-thermal coupling monitoring method of the heat sink molten salt pipeline can accurately reflect the fluid state change at the low point, and provide reliable basis for accurate determination of the heat sink salt removal process.

[0028] The meteorological data of the heat sink field area is obtained through the meteorological monitoring station arranged in the heat sink field area, and a solar tracker and a sunshine intensity meter are provided in the meteorological station to measure the solar elevation angle in real time; the wind speed monitoring of the heat sink field area uses a three-dimensional ultrasonic wind speed meter, which is installed at a position 0.7 times the height of the center of the heat sink, measures the horizontal and vertical wind speed components, and integrates the horizontal and vertical wind speed components to obtain the wind speed vector module , and the wind speed change rate calculation formula is: , , where represents the wind speed change rate.

[0029] All collected data is transmitted to the central data processing server through industrial Ethernet, and data quality checking is performed on the server side, including range verification, sudden change detection and missing value interpolation. For abnormal data beyond the normal range, automatic marking and secondary confirmation mechanism are triggered. For example, when the measurement value of a certain temperature sensor suddenly jumps from 300°C to 800°C, the server side calls the adjacent sensor data for cross verification, if the adjacent sensor temperature is about 320°C, the data is determined to be abnormal and corrected by interpolation method and the sensor is recalibrated.

[0030] This step builds a multi-source synchronous data acquisition system to comprehensively grasp the thermal distribution state, local fluid dynamic characteristics and external environmental changes of the heat sink, providing rich, accurate and real-time data basis for subsequent thermal management state judgment, which can significantly improve the intelligent level and fault warning ability of heat sink operation monitoring.

[0031] Step 2: In the heat sink running state, the distributed temperature data of the heat sink is three-dimensionally reconstructed and time-sequentially registered to generate real-time thermal cloud map, segment and identify temperature abnormal area, calculate comprehensive index representing spatial thermal imbalance degree, and standardize and quantify thermal equilibrium level. Referring to Figure 2 , the flow chart of this step for thermal equilibrium evaluation in running state.

[0032] In the heat sink running state, the distributed temperature data collected is processed by three-dimensional spatial reconstruction. First, a three-dimensional coordinate system of the heat sink tube screen is established, taking the geometric center of the heat sink tube screen 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 position of each temperature sensor is mapped into the three-dimensional coordinate system to form a discrete temperature sampling point set. Radial basis function interpolation method is used to interpolate the discrete temperature points to construct a continuous temperature field distribution function , wherein represents the temperature value, represents the spatial coordinate, represents the time, and in the interpolation process of the temperature field distribution function, Gaussian kernel function is introduced as the weight factor to ensure the smooth transition of the temperature field and the preservation of local features.

[0033] Based on the registered temperature field data, real-time thermal cloud map is generated, and volume rendering technology is used to project three-dimensional temperature field to two-dimensional display plane. Temperature value is converted to RGB color value through color mapping table, and temperature range can be mapped from low to high to blue, green, yellow and red color system in turn to form intuitive thermal distribution visualization effect. The cloud map update frequency can be set to once per minute, and the cloud map update frequency can be set according to the demand to realize dynamic monitoring of different needs. The visualization method enables the operation personnel to quickly identify the temperature distribution pattern and abnormal area.

[0034] For the identification of temperature abnormal area, gradient-based edge detection algorithm combined with statistical threshold judgment method is adopted to calculate the spatial gradient of the temperature field. When the gradient value exceeds the set threshold, it is marked as potential abnormal boundary. At the same time, the temperature statistical characteristics of local area are calculated, including mean and standard deviation , wherein represents the th local area. When the temperature value of a certain area meets , it is determined as abnormal area. represents local temperature, represents global temperature mean and standard deviation, respectively, is an abnormality determination coefficient. For example, if the global average temperature is 550°C and the standard deviation is 30°C when the heat absorber is running normally, if the temperature of a local area is above 640°C or below 460°C, it is identified as a temperature abnormal area.

[0035] To quantify the degree of spatial thermal imbalance and construct a comprehensive evaluation index system, the spatial unevenness coefficient of temperature distribution is calculated first represents the spatial unevenness coefficient, represents the spatial temperature standard deviation, represents the spatial temperature mean; then the kurtosis value of temperature gradient distribution is calculated represents the gradient kurtosis, represents the gradient value, represents the mean and standard deviation of the gradient, respectively, represents the mathematical expectation operation; finally, the abnormal area ratio is calculated represents the abnormal area ratio, represents the abnormal area volume, represents the total volume of the heat absorber.

[0036] The above three indexes are fused by weighting to form a comprehensive index of spatial thermal imbalance: represents the comprehensive index of thermal imbalance, is a weight coefficient, satisfying .The weight coefficient is determined by the analytic hierarchy process, and can also be assigned according to the influence of each index on the safe operation of the heat absorber. For example, according to the comprehensive index value The thermal equilibrium is divided into five levels: excellent ( ), good ( ), general ( ), poor ( ), and dangerous ( ).

[0037] ​​​​​​​​​The step can comprehensively depict the thermal distribution characteristics of the heat absorber during operation by the multi-dimensional temperature field analysis and quantitative evaluation method, can timely find the local overheating or overcooling area, provide accurate state evaluation basis for operation regulation and control, effectively prevent the thermal stress damage and operation failure caused by uneven temperature distribution, and improve the safety and economy of the heat absorber operation.

[0038] Step 3: Fuse meteorological data and thermal equilibrium level to build a working condition conversion prediction model based on multi-dimensional information fusion, output working condition conversion coefficient, and determine whether to issue working condition conversion instruction according to the working condition conversion coefficient to control whether the heat absorber enters the salt-removing state from the running state. Referring to Figure 3 The working condition conversion prediction and instruction issuing flowchart provided for the step is as follows.

[0039] The meteorological data is preprocessed and feature extracted, and the collected solar elevation angle change rate and wind speed change rate data are subjected to sliding window smoothing processing, and the window length is set to 5 minutes to eliminate the influence of instantaneous disturbance on the judgment. The meteorological stability index is defined as , wherein represents the meteorological stability index, represents the solar elevation angle change rate, represents the wind speed change rate, and are normalization coefficients for adjusting the influence weight of solar elevation angle change and wind speed change on stability. When the meteorological condition changes dramatically, the value tends to 0, indicating that the external disturbance is large; when the meteorological condition is stable, the value tends to 1.

[0040] The thermal equilibrium level is numerically mapped, the excellent level is mapped to 1.0, the good level is mapped to 0.8, the general level is mapped to 0.6, the poor level is mapped to 0.4, and the dangerous level is mapped to 0.2. The mapping relationship can directly represent that the better the thermal state is, the higher the corresponding numerical value is. At the same time, the time derivative of the thermal equilibrium is introduced , wherein represents the thermal equilibrium change rate, represents the thermal equilibrium value at the current time, is the sampling time interval. The time derivative of the thermal equilibrium reflects the dynamic change trend of the thermal state, and the positive value represents the improvement of the thermal state, and the negative value represents the deterioration of the thermal state.

[0041] The fusion decision function of the working condition conversion prediction is established, and the meteorological stability, the thermal equilibrium and the change trend are comprehensively considered. The working condition conversion coefficient is defined as , and the specific calculation formula is: , wherein represents the working condition conversion coefficient, 、 、 is the weight parameter, satisfying . Reflecting the promoting effect of meteorological instability on the conversion of working conditions, Reflects the need for working condition conversion due to poor thermal conditions. The influence of the deterioration trend of thermal state is considered; The function ensures that the operating condition conversion coefficient is increased only when the meteorological stability and thermal equilibrium show a deteriorating trend.

[0042] To improve the accuracy of the operating condition conversion prediction model, an adaptive learning mechanism based on historical operating data is introduced to establish a historical operating condition conversion event database, recording the meteorological conditions and thermal status before each operating condition conversion and the operating results after the conversion. The Bayesian update method is used to dynamically adjust the weight parameters, and the update formula is: ,in Indicates the updated weights, represents the weight before update, represents the learning rate, Indicates the actual operation effect score, It represents the prediction effect score. The constructed adaptive mechanism enables the operating condition conversion prediction model to continuously optimize the decision parameters based on actual operating experience.

[0043] Set the judgment threshold for working condition conversion , when the working condition conversion coefficient When the threshold is determined, it is determined that the working mode needs to be switched. The risk-benefit balance principle is adopted to comprehensively consider the necessity of salt removal operation and the equipment loss caused by frequent switching. When it is set to 0.5, if the meteorological stability index at a certain moment (Indicates that the weather changes greatly), thermal balance value (corresponding to the poor grade), thermal balance change rate (indicates state deterioration), the weight parameters are set as 、 、 , then we can calculate ,because , then issue a working mode conversion command.

[0044] When it is determined that the operating condition needs to be converted, an operating condition conversion control instruction is generated, and the heat absorber is converted from the operating turntable to the salt-removing state. At the same time, the operating condition conversion early warning mechanism is activated to notify the operating personnel in advance to make corresponding preparations and realize safe switching of human-machine collaboration.

[0045] The step can accurately grasp the best time of working condition conversion by comprehensively considering external environment changes and internal thermal state through the multi-dimensional information fusion pre-judgment method, avoids one-sidedness and hysteresis of single index judgment, reduces unnecessary working condition switching, can prolong the service life of the equipment, at the same time ensures timely entering the salt-bleeding state when necessary, and guarantees the safe and stable operation of the heat absorber.

[0046] Step 4: In the salt-bleeding state of the heat absorber, the acoustic signals of the low points of the heat absorber during salt-bleeding are obtained, and the frequency band energy is extracted, and the cooling rate curve of the tube wall temperature is recorded, the synchronization characteristics of flow energy attenuation and cooling rate turning point are detected, and whether the local salt-bleeding of the corresponding monitoring point is completed is judged. Referring to Figure 4 The salt-bleeding state local salt-bleeding completion judgment flow chart is provided for the step.

[0047] After the heat absorber enters the salt-bleeding state, the acoustic signals of the low points of the heat absorber need to be continuously collected and analyzed in real time to ensure the safety and stability of the salt-bleeding process.

[0048] During the salt-bleeding process, the turbulent noise generated by the flow of molten salt in the tube, the bubble breaking sound and the sound of solid-liquid interaction constitute a complex acoustic characteristic spectrum. The short-time Fourier transform method is used for time-frequency analysis of the acoustic signal, and the time-domain signal is converted to the time-frequency domain to obtain the time-frequency spectrum , wherein represents the time-frequency spectrum, is an imaginary unit, represents the original acoustic signal, represents the window function, represents the frequency, represents the integral variable. The Hamming window is used as the window function, and the window length can be set to 256 sampling points, and the overlap rate is 50%, so as to ensure the balance of time-frequency resolution.

[0049] The time-frequency spectrum is divided into three characteristic frequency bands for energy extraction: the low frequency band (10Hz-500Hz) mainly reflects the large-scale flow characteristics, the medium frequency band (500Hz-3kHz) corresponds to the turbulent mixing and bubble movement, and the high frequency band (3kHz-10kHz) contains the solid particle collision and micro-bubble breaking information.

[0050] The energy distribution of each frequency band is calculated , wherein represents the energy of the th frequency band, and respectively represent the lower limit and upper limit frequency of the th frequency band, and the time evolution characteristics of the energy of each frequency band are monitored to identify different stages of the salt-bleeding process.

[0051] Synchronous recording of tube wall temperature data, construction of cooling rate curve, calculation of instantaneous cooling rate wherein represents the cooling rate, represents the tube wall temperature; numerical differential calculation is performed using a five-point difference method to reduce the influence of measurement noise, the cooling rate curve is piecewise fitted, and the rate turning point is identified. In the initial stage of salt removal, the molten salt in the tube is rapidly discharged, the tube wall loses the heat source, and the cooling rate is large; after the molten salt is basically emptied, the cooling rate will have a significant downward turning point, and this downward turning point is an important feature for determining the completion of salt removal.

[0052] An association analysis model of acoustic energy decay and cooling rate turning is established, and an acoustic energy decay index is defined wherein represents the acoustic energy decay index, represents the total acoustic energy at the moment, represents the total acoustic energy at the moment when salt removal starts; when drops to a set energy decay threshold the following times, indicating that the fluid kinetic energy is significantly reduced. At the same time, the second derivative of the cooling rate is detected , when it changes from negative to positive, it indicates that the molten salt cooling process enters the slow stage.

[0053] A comprehensive determination criterion for the completion of salt removal is constructed, and three conditions need to be met simultaneously for the completion of salt removal: 1) the acoustic energy decay index wherein is the energy decay threshold; 2) the cooling rate wherein is the rate threshold; 3) the sign of the second derivative of the cooling rate changes. For example, if a certain low point of the heat absorber pipeline shows that the total acoustic energy at the start of salt removal is 85 dB, which drops to 32 dB after 12 minutes, the calculated ; at the same time, the tube wall temperature drops from 320°C to 180°C, the cooling rate drops from the initial 15°C / min to 2°C / min, and the second derivative changes from -0.8°C / min² to 0.2°C / min². When the set , ℃ / min, then the monitoring point meets the salt removal completion determination condition.

[0054] A hierarchical salt removal completion confirmation mechanism is implemented, and the completion of salt removal is divided into three levels of preliminary completion, basic completion and complete completion. Preliminary completion means that the main molten salt has been discharged, basic completion means that the amount of residual molten salt is very small, and complete completion means that the pipeline is completely empty. Each level corresponds to different determination standards and subsequent operation strategies to realize the fine management of the heat absorber salt removal process.

[0055] This step realizes non-destructive real-time monitoring of the desalination process through collaborative analysis of acoustic signals and temperature signals, avoids the drawbacks of traditional methods that require shutdown inspection, and significantly improves desalination efficiency and accuracy. This step is based on a multi-physical field coupling determination method that can accurately capture the dynamic characteristics of the desalination process, providing reliable technical support for the safe switching and efficient operation of the heat absorber.

[0056] Step 5: Establish a heat absorber thermal health state matrix, unify the heat balance level of the heat absorber with the desalination completion flag of each low point, index by tube panel number and pipeline topology, and perform real-time updating and historical tracing.

[0057] A heat absorber thermal health state matrix is constructed, and a multi-dimensional matrix structure is used to store and manage the comprehensive state information of the heat absorber. The state matrix is defined as wherein represents the state value of the th tube panel at the th monitoring position at the th moment, is the tube panel number index, is the monitoring position index, is the time index. The rows of the matrix correspond to different tube panels, the columns correspond to each monitoring position, and the depth dimension records time series data. Each matrix element contains two key information: heat balance level value and desalination completion flag, which are packaged and stored using a composite data structure.

[0058] A mapping relationship between tube panel number and physical location is established, and the system is coded according to the actual arrangement structure of the heat absorber. For example, the tube panel number uses a three-part coding rule: the first part represents the orientation, the second part represents the vertical level, and the third part represents the horizontal serial number. For example, the number "N-3-5" represents the 3rd tube panel on the north side. Each tube panel has multiple monitoring position sub-nodes, including tube panel surface temperature monitoring points, low point acoustic monitoring points, and valve position monitoring points. Through this hierarchical coding system, accurate mapping from physical space to data space is achieved.

[0059] For the pipeline topology structure, an adjacency relationship matrix is constructed wherein represents the connection relationship between tube panel and tube panel , when the two are directly connected , otherwise . Through the adjacency matrix, the heat transfer path and fault propagation link can be quickly represented. During state updating, the topological relationship is used for correlation analysis. When an abnormality occurs in a tube panel, the states of its adjacent tube panels are checked, which can realize early warning and diffusion path prediction of faults.

[0060] A unified mapping mechanism of thermal equilibrium level and salt-leaching completion flag is implemented. Five levels of thermal equilibrium (excellent, good, general, poor, and dangerous) are encoded as 5, 4, 3, 2, and 1, respectively, and the salt-leaching completion flag is encoded as a binary flag, where 1 represents completion and 0 represents non-completion or in progress. A comprehensive health index is defined , wherein represents the comprehensive health index of the m-th tube panel at the n-th position, represents the normalized thermal equilibrium level value, represents the salt-leaching completion flag, and are weight coefficients satisfying . The unified mapping mechanism of thermal equilibrium level and salt-leaching completion flag unifies multi-source heterogeneous state information into the same evaluation system.

[0061] A real-time updating mechanism is established. When the sensor acquisition frequency is set to 0.1 Hz, the data refresh period is set to 10 seconds to ensure that the state matrix reflects the latest operating conditions of the heat absorber. The updating process adopts an incremental strategy, which only modifies the matrix elements that have changed, reducing the computational overhead. A state change rate is defined , wherein represents the state change rate, represents the number of monitoring points that have changed per unit time, and represents the total number of monitoring points. When the state change rate exceeds the set state change rate threshold , a global state assessment is triggered, and the overall health index of the heat absorber is recalculated. The state change rate threshold can be set to a large value to avoid frequent global state assessments.

[0062] A historical data tracing system is constructed, and historical state matrices are stored using a timestamp indexing method. For example, the data saving strategy is set to save complete records of the last 72 hours of real-time data, save daily statistical data for the last 30 days, and save monthly summary data permanently. Historical data is stored using compression technology, and the LZ77 algorithm is selected as the compression algorithm to reduce storage space occupation while ensuring data integrity. A fast retrieval mechanism is established to support multi-dimensional queries of historical records by time period, tube panel number, state level, etc.

[0063] A state trend analysis function is implemented to identify the state evolution law through statistical analysis of historical data. A state stability index is calculated , wherein represents the stability index, represents the number of sampling points in the statistical period, and​​ the health value at the moment, representing the average health. For example, the health values of a certain tube screen in the past 24 hours are 4.2, 4.1, 3.9, 4.0, and 3.8, respectively, and the average value is calculated as 4.0, and the stability index indicates that the state of the tube screen is relatively stable.

[0064] An abnormal state alarm mechanism is created, and when a sharp decrease in health or a salt leakage anomaly is detected, an alarm information is automatically generated. The alarm information includes the abnormal position, the abnormal type, and the severity content, and the running personnel is reminded through a visual interface and a sound and light alarm. A hierarchical response mechanism is established, and different levels of emergency plans are triggered according to the severity of the anomaly.

[0065] This step realizes the comprehensive monitoring and scientific management of the operating state of the heat absorber by establishing such a perfect thermal health state matrix management mechanism, provides data support for operation decision-making, improves the accuracy of fault diagnosis and the pertinence of maintenance plan, can effectively prolong the service life of the heat absorber equipment, and ensures the long-term safe and stable operation of the heat absorber.

[0066] Embodiment 2 The second embodiment of the present application provides a start-up process of a heat absorber in a functional working state.

[0067] The operation process of the heat absorber includes a preheating state before start-up, a standby state, a running state, a salt leakage state, and a shutdown state.

[0068] The triggering conditions of the preheating state include: about 4 hours before sunrise, the electric heat tracing system of the molten salt pipeline is started according to the actual configuration power grouping control; the meteorological monitoring system determines that the running conditions are met on the same day; the wind speed is less than the set value 18 m / s (10 m high air in 10 min average wind speed); the meteorological condition judgment in the preheating state of the heat absorber can adopt two ways of cloud monitoring system or manual judgment.

[0069] Since the heat absorber system is the potential freezing point of the molten salt, the electric heat tracing system (including the container, the pipeline, the valve and other) is used for molten salt anti-condensation and daily preheating; the electric heat tracing system has the ability to heat and keep the molten salt pipeline, valve and container at 300℃.

[0070] The triggering actions of the preheating state include starting the electric heat tracing system; when the DNI is greater than 50 W / m2, starting the mirror field to preheat the heat absorber.

[0071] The end conditions of the preheating state include that the temperature of the molten salt pipeline system is greater than 300℃, and the average temperature of all heat absorber panels is greater than 300℃.

[0072] The trigger conditions of the standby state include that the meteorological system determines that the operation condition is met, the molten salt pipeline is preheated, the wind speed is less than the set value of 18 m / s (the average wind speed at 10 m high in 10 min), the heat absorber system equipment diagnosis is normal, and the air pressure system establishes pressure. The meteorological condition judgment in the standby state of the heat absorber can adopt two ways of cloud monitoring system or manual judgment.

[0073] The trigger actions of the standby state include starting the cold salt pump, establishing the ascending pipe, the heat absorber bypass pipe and the descending pipe circulation.

[0074] The end conditions of the standby state include that the outlet buffer tank establishes the liquid level.

[0075] The trigger conditions of the operation state include that the meteorological function determines that the heat absorber has the salt feeding condition, the heat absorber panel is preheated, the wind speed is less than the set value of 18 m / s (the average wind speed at 10 m high in 10 min), the heat absorber system equipment diagnosis is normal, and the air pressure system establishes pressure. The meteorological condition judgment in the operation state of the heat absorber can adopt two ways of cloud monitoring system or manual judgment.

[0076] The actions of the operation state include opening the heat absorber exhaust and salt flushing valves, feeding salt into the heat absorber body, closing the exhaust and salt flushing valves after the salt feeding into the heat absorber body is completed, establishing the serial process of the heat absorber, gradually putting in the mirror field energy until all the mirror field energy is put in, adjusting the heat absorber inlet flow to maintain the heat absorber outlet salt temperature to reach 565 ℃, and when the heat absorber outlet salt temperature is less than 400 ℃, entering the cold salt tank, and when the heat absorber outlet salt temperature is greater than 400 ℃, entering the hot salt tank, and the switching temperature of 400 ℃ can be adjusted according to the design temperature of the storage tank.

[0077] The heat absorber outlet molten salt temperature is adjusted through the frequency conversion of the molten salt pump, and when the flow deviation occurs between the two branches of the heat absorber, the inlet adjusting valve is adjusted.

[0078] The end conditions of the operation state include that the heat absorber outlet molten salt temperature reaches 565 ℃.

[0079] The trigger conditions of the salt flushing state include that the meteorological function determines that the heat absorber does not have the operation condition, the solar elevation angle is less than 5°, and the wind speed is greater than the set value of 18 m / s (the average wind speed at 10 m high in 10 min). The actions of the salt flushing state include that the mirror field is defocused, a small part of the heliostat maintains the heat absorber at 300 ℃, the cold salt pump is closed, and the exhaust valve and the salt flushing valve are opened for salt flushing.

[0080] The end conditions of the salt flushing state include that the heat absorber salt flushing is completed (30 min after the salt flushing, and the total molten salt mass in the storage tank is restored to the previous day shutdown level).

[0081] The trigger conditions of the shutdown state include that the salt flushing is completed.

[0082] The triggering action of the shutdown state includes that the mirror field is restored to the initial position; the electric heat tracing system is turned off (the valve electric heat tracing can be retained).

[0083] The condition of the end of shutdown includes that the mirror field and the electric heat tracing system have been turned off completely.

[0084] Embodiment 3 Reference Figure 5 For the third embodiment of the present application, a heat sink start-stop process thermal management state determination device is provided.

[0085] The device comprises a data acquisition module, a thermal balance evaluation module, a state conversion module, a shutdown detection module, and a management and maintenance module.

[0086] The data acquisition module acquires distributed temperature data of the heat sink tube panel through a temperature sensor, acquires acoustic data and low-point temperature data of the heat sink pipeline low point, and acquires meteorological data of the environment to which the heat sink belongs, forming a synchronous data stream of space thermal force, local fluid dynamics, and meteorological changes.

[0087] The thermal balance evaluation module, in the heat sink running state, performs three-dimensional reconstruction and time sequence registration on the distributed temperature data of the heat sink, generates a real-time thermal force cloud map, segments and identifies temperature abnormal areas, calculates a comprehensive index representing the degree of spatial thermal imbalance, and standardizes and quantizes the thermal balance level.

[0088] The state conversion module fuses meteorological data and thermal balance levels, constructs a working condition conversion prediction model based on multi-dimensional information fusion, outputs a working condition conversion coefficient, discriminates whether to issue a working condition conversion instruction according to the working condition conversion coefficient, and controls whether the heat sink enters a salt dissipation state from a running state.

[0089] The shutdown detection module, in the heat sink salt dissipation state, acquires acoustic signals of each low point of the heat sink during salt dissipation and extracts frequency band energy, records the cooling rate curve of the tube wall temperature at the same time, detects the synchronous characteristics of flow energy attenuation and cooling rate turning point, and determines whether the local salt dissipation of the corresponding monitoring point is completed.

[0090] The management and maintenance module establishes a heat sink thermal health state matrix, uniformly maps the thermal balance level of the heat sink and the salt dissipation completion flag of each low point, indexes according to the tube panel number and pipeline topology, and performs real-time updating and historical tracing.

[0091] In the embodiments of the present application, it should be understood that the disclosed apparatus and method can be implemented in other manners. The embodiments described above are merely exemplary, and are not intended to limit the application. For example, the division of the units is only a logical function division, and there can be another division manner in actual implementation; for example, a plurality of units or components can be combined or integrated into another system, or some features can be ignored or not executed. In addition, the displayed or discussed mutual couplings or direct couplings or communication connections can be indirect couplings or communication connections through some interfaces, devices or units, and can be in electrical, mechanical or other forms.

[0092] The embodiments of the present application are described above with reference to the accompanying drawings, but the present application is not limited to the above-mentioned specific embodiments, and the above-mentioned specific embodiments are merely illustrative, but not restrictive. Those skilled in the art can make changes, modifications, replacements and variations to the above-mentioned embodiments without departing from the scope of the present application and the scope of protection of the claims, and these are all within the protection scope of the present application.

Claims

1. A method for determining the thermal management state of a heat absorber during start-up and shutdown, characterized in that: include: The distributed temperature data of the absorber tube panel is collected through temperature sensors, as well as the acoustic data and low-point temperature data of the absorber pipeline, and the meteorological data of the environment to which the absorber belongs is obtained, forming a synchronous data stream of spatial thermal, local fluid dynamics and meteorological changes; When the heat sink is in operation, the distributed temperature data of the heat sink is 3D reconstructed and time-series registered to generate a real-time thermal cloud map, segment and identify temperature anomaly areas, calculate a comprehensive index representing the degree of spatial thermal imbalance, and standardize and quantify the thermal balance level; By integrating meteorological data and thermal balance levels, a working condition conversion prediction model based on multi-dimensional information fusion is constructed, which outputs the working condition conversion coefficient. Based on the working condition conversion coefficient, it is determined whether to issue a working condition conversion instruction and control whether the heat absorber switches from the operating state to the salt-removing state. When the heat absorber is in the salt-removing state, the acoustic signals of each low point of the heat absorber are obtained and the frequency band energy is extracted. At the same time, the cooling rate curve of the pipe wall temperature is recorded, and the synchronous characteristics of the flow energy attenuation and the cooling rate turning point are detected to determine whether the local salt removal at the corresponding monitoring point is completed. Establish a thermal health status matrix for the heat absorber, uniformly map the thermal balance level of the heat absorber with the salt removal completion mark of each low point, index it by tube panel number and pipeline topology, and perform real-time updates and historical tracing.

2. The method for determining the thermal management state of a heat absorber during start-up and shutdown according to claim 1, characterized in that: Distributed temperature data is collected on the surface of the absorber tube panel; acoustic sensors and temperature sensors are deployed at the low points of the absorber pipeline, and the low-point acoustic data and low-point temperature data are collected synchronously; the solar altitude angle and wind speed change rate are obtained respectively through the sun tracker and anemometer equipped at the meteorological monitoring station in the absorber area.

3. The method for determining the thermal management state of a heat absorber during start-up and shutdown according to claim 2, characterized in that: When the heat sink 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 series registration is performed to eliminate time deviations. Generate real-time thermal cloud images based on the registered temperature field data, and visualize the temperature distribution intuitively through volume rendering technology projection and color mapping; A gradient-based edge detection algorithm combined with a statistical threshold judgment method is used to segment and identify abnormal temperature areas, calculate the spatial gradient of the temperature field, and determine whether the temperature in the local area exceeds the normal range.

4. The method for determining the thermal management state of a heat absorber during start-up and shutdown according to claim 3, characterized in that: A comprehensive evaluation index system was constructed to quantify the degree of spatial thermal imbalance, including: calculating the spatial nonuniformity coefficient of temperature distribution, the kurtosis value of temperature gradient distribution, and the proportion of abnormal areas; The spatial unevenness coefficient, kurtosis value and proportion of abnormal areas are weightedly 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 state of a heat absorber during start-up and shutdown according to claim 4, characterized in that: The collected meteorological data is preprocessed and features extracted, the solar altitude angle change rate and wind speed change rate data are smoothed through a sliding window, and meteorological stability indicators are defined; The thermal balance level is numerically mapped and the time derivative of thermal balance is introduced to represent the dynamic trend of thermal state. A fusion decision function is established to integrate meteorological stability indicators, thermal equilibrium and dynamic change trends of thermal status, and define the operating condition conversion coefficient.

6. The method for determining the thermal management state of a heat absorber during start-up and shutdown according to claim 5, characterized in that: An adaptive learning mechanism based on historical operating data is introduced to establish a historical operating condition conversion event database, and the Bayesian update method is used to dynamically adjust the weight parameters of the operating condition conversion coefficient; Set the judgment threshold for working condition conversion, which is determined by the risk-benefit balance principle; When the operating condition conversion coefficient exceeds the judgment threshold of the operating condition conversion, it is determined that the operating condition conversion is required, and an operating condition conversion control instruction is generated to control the heat absorber from the operating state to the salt-removing state.

7. The method for determining the thermal management state of a heat absorber during start-up and shutdown according to claim 6, characterized in that: When the heat absorber enters the salt-removing state, the acoustic signals at each low point are continuously collected and analyzed in real time; Short-time Fourier transform method is used for time-frequency analysis, which is divided into multiple characteristic frequency bands for frequency band energy extraction to identify different stages of the salt removal process. The pipe wall temperature data was obtained, 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 fitted piecewise to identify the turning point of the salt removal rate.

8. The method for determining the thermal management state of a heat absorber during start-up and shutdown according to claim 7, characterized in that: Establish a correlation analysis model between acoustic energy attenuation and cooling rate transition, define the acoustic energy attenuation index, and detect the sign transition of the second derivative of the cooling rate; A comprehensive criterion for determining whether the heat absorber has completed salt removal 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. Build a salt removal completion confirmation mechanism and divide the salt removal completion status into multiple levels.

9. The method for determining the thermal management state of a heat absorber during start-up and shutdown according to claim 8, characterized in that: Construct a heat sink thermal health status matrix, using a multi-dimensional matrix structure to store comprehensive status information including thermal balance level values ​​and salt removal completion flags; Establish a mapping relationship between the tube panel number and the physical location, and build an adjacency relationship matrix based on the pipeline topology structure; implement a unified mapping mechanism between the thermal balance level and the salt removal completion mark, and define a comprehensive health indicator; establish a real-time update mechanism to reflect the latest operating status of the heat absorber, and build a historical data traceability mechanism.

10. A device for determining the thermal management state of a heat absorber during start-up and shutdown, which is implemented based on the method for determining the thermal management state of a heat absorber during start-up and shutdown according to any one of claims 1 to 9, and is characterized in that: include: Data acquisition module, thermal balance assessment module, state conversion module, shutdown detection module and management and maintenance module; The data acquisition module collects distributed temperature data of the absorber tube panel through temperature sensors, collects acoustic data and low-point temperature data of the absorber pipeline, and obtains meteorological data of the environment to which the absorber belongs, forming a synchronous data stream of spatial thermal, local fluid dynamics and meteorological changes; The thermal balance assessment module, when the heat absorber is in operation, performs three-dimensional reconstruction and time-series registration on the distributed temperature data of the heat absorber to generate a real-time thermal cloud map, segment and identify temperature anomaly areas, calculate a comprehensive index representing the degree of spatial thermal imbalance, and standardize and quantify the thermal balance level; The state conversion module integrates meteorological data and thermal balance level, builds a working condition conversion prediction model based on multi-dimensional information fusion, outputs the working condition conversion coefficient, and determines whether to issue a working condition conversion instruction based on the working condition conversion coefficient to control whether the heat absorber enters the salt-removing state from the operating state; The shutdown detection module, when the heat absorber is in the salt-removing state, obtains the acoustic signals of each low point of the heat absorber during salt removal and performs frequency band energy extraction. At the same time, it records the cooling rate curve of the pipe wall temperature, detects the synchronous characteristics of flow energy attenuation and cooling rate turning point, and determines whether the local salt removal of the corresponding monitoring point is completed; The management and maintenance module establishes a thermal health status matrix for the heat absorber, uniformly maps the thermal balance level of the heat absorber with the salt removal completion mark of each low point, indexes it according to the tube panel number and pipeline topology, and performs real-time updates and historical tracing.

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