CN117307266B - Control system for vortex cavitation flow in low-temperature liquid expander - Google Patents
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Abstract
The invention discloses a control system for vortex cavitation flow in a low-temperature liquid expander, relates to the technical field of low-temperature air separation and low-temperature liquefaction, and solves the technical problems that a model established in the prior art is difficult to solve, a control target is single, and vortex cavitation is difficult to inhibit efficiently; judging whether cavitation inhibition is needed according to cavitation data or by combining cavitation data collected in history; combining the mapping relation between the restraint parameters, the cavitation degree and the pressure data change, identifying a cavitation restraint range capable of restraining cavitation and guaranteeing the working state of the low-temperature liquid expander, then combining the energy consumption of the control process to screen out a proper cavitation restraint sequence from the cavitation restraint range, and controlling the low-temperature liquid expander according to the cavitation restraint sequence to finish cavitation restraint; the invention can ensure the output pressure of the low-temperature liquid expander and simultaneously inhibit the output pressure effectively.
Description
Technical Field
The invention belongs to the field of low-temperature air separation and low-temperature liquefaction, relates to a technology for controlling vortex cavitation flow in a low-temperature liquid expander, and particularly relates to a control system for vortex cavitation flow in the low-temperature liquid expander.
Background
The cryogenic liquid expander is used as a hydraulic machine, and cavitation is inevitably generated, similar to the conventional hydraulic (or hydrodynamic) machine. The collapse of cavitation bubbles can generate extremely high local pressure, so that great impact is caused on structural surface materials, and cavitation corrosion damage is generated; and the vibration of the unit can be induced, and the stable operation of the liquid expander and even the low-temperature system is threatened.
The prior art (the patent of the invention with the application number of 2018100087484) discloses an effective control method for vortex cavitation flow in a low-temperature liquid expander, which considers the research of vortex cavitation mechanism of the low-temperature liquid expander by using the thermodynamic effect of low-temperature fluid, the sensitivity analysis of impeller geometric parameters of vortex cavitation flow in the low-temperature liquid expander, the characterization expression of complex vortex cavitation flow in the low-temperature liquid expander, the construction of a flow field optimization objective function and a flow field optimization control variable for controlling the vortex cavitation flow and the parallel solving of the vortex cavitation flow optimization control problem. In the prior art, a flow field optimization control variable is obtained by solving established models, the construction of the models is closely related to various parameters of the low-temperature liquid expander, and once the parameters are changed, the models are possibly inapplicable; moreover, the process optimization control variables are all used for realizing the control of the impeller, but the rotation of the impeller is not the only factor for generating vortex cavitation, which can cause difficulty in efficiently inhibiting the generation of vortex cavitation.
The invention provides a control system for vortex cavitation flow in a low-temperature liquid expander, which aims to solve the technical problems.
Disclosure of Invention
The present invention aims to solve at least one of the technical problems existing in the prior art; therefore, the invention provides a control system for vortex cavitation flow in a low-temperature liquid expander, which is used for solving the technical problems that a model established in the prior art is high in solving difficulty, single in control target and difficult to efficiently inhibit vortex cavitation.
In order to achieve the above object, a first aspect of the present invention provides a control system for vortex cavitation flow in a low-temperature liquid expander, including a central control module, and a data acquisition module and an execution control module connected with the central control module; the data acquisition module is connected with a data sensor arranged in the low-temperature liquid expander; the data sensor comprises a cavitation monitor, a flow sensor, a temperature sensor and a rotating speed sensor; a central control module: monitoring cavitation data in the low-temperature liquid expander through a cavitation monitor connected with the data acquisition module; judging whether cavitation suppression is carried out or not based on the monitored cavitation data; if yes, cavitation inhibition is carried out; if not, continuously analyzing cavitation data; and constructing a cavitation target sequence based on the cavitation data and the pressure data; constructing cavitation input data according to the restraint parameters, inputting the cavitation input data into a cavitation optimization model, and screening model output results through a cavitation target sequence to obtain a cavitation restraint sequence; and the control execution control module performs cavitation suppression on the low-temperature liquid expander according to the cavitation suppression sequence.
Judging whether cavitation inhibition is needed according to cavitation data or by combining cavitation data collected in history; and identifying a cavitation inhibition range which can inhibit cavitation and ensure the working state of the low-temperature liquid expander according to the mapping relation between the inhibition constraint parameters, the cavitation degree and the pressure data change, screening out a proper cavitation inhibition sequence from the cavitation inhibition range according to the energy consumption of the control process, and controlling the low-temperature liquid expander according to the cavitation inhibition sequence to finish cavitation inhibition. The invention can ensure the output pressure of the low-temperature liquid expander and simultaneously inhibit the output pressure effectively.
The central control module is respectively in communication and/or electric connection with the data acquisition module and the execution control module; the execution control module is used for controlling the low-temperature liquid expander; the data acquisition module is in communication and/or electrical connection with a data sensor arranged inside or outside the low-temperature liquid expansion machine; and the data acquired by the data acquisition module is stored in the central control module. The central control module is mainly responsible for data processing to acquire cavitation inhibition sequences; the data acquisition module is mainly used for acquiring cavitation data, liquid flow data, internal temperature data, rotating speed and torque data of the impeller and the like in the low-temperature liquid expander through a data sensor; the execution control module controls the low-temperature liquid expander according to the cavitation suppression sequence to realize cavitation suppression.
Preferably, the determining whether to perform cavitation suppression based on the monitored cavitation data includes: extracting the monitored cavitation data, and converting the cavitation data into cavitation degrees; judging whether the cavitation degree is larger than a set degree threshold value; if yes, cavitation inhibition is carried out; if not, continuously collecting cavitation data; or constructing a cavitation variation curve based on the monitored cavitation data, and judging whether cavitation inhibition is needed based on the variation trend of the cavitation variation curve.
In the first step of cavitation suppression, it is necessary to determine whether cavitation occurs in the cryogenic liquid expander and whether the degree of cavitation reaches the level to be suppressed. Comparing the current cavitation data with the cavitation degree, and judging whether the current cavitation degree needs to be inhibited or not; or judging whether the cavitation degree presents an ascending trend or not according to the historical cavitation data, and further judging whether cavitation inhibition is needed or not. The invention evaluates the current state and the future state, can complete cavitation suppression as early as possible, and improves the cavitation suppression efficiency.
Preferably, the determining whether cavitation suppression is needed based on the change trend of the cavitation change curve includes: setting a plurality of setting periods according to the independent variable value range of the cavitation variation curve, and uniformly determining a plurality of period moments in each setting period; calculating a first derivative value of each period moment based on the cavitation variation curve; calculating the first derivative mean value of a plurality of period moments in the same set period; when the mean value of the first derivative corresponding to a plurality of set periods is in an ascending trend, cavitation suppression is carried out; otherwise, continuously analyzing the change trend.
In some cases, the current cavitation level may not be high, and cavitation suppression is not required; when the cavitation degree is improved very rapidly, the degree threshold value is exceeded in a short time, and if cavitation data is still converted into cavitation degree in real time, the cavitation inhibition time is obviously delayed by judging. Therefore, the invention can analyze the change trend of the cavitation degree when the current cavitation degree does not need cavitation inhibition.
The cavitation change curve is constructed by taking time as an independent variable and the cavitation degree corresponding to cavitation data conversion as the dependent variable. Dividing the time range of the independent variable into a plurality of set periods, such as 1 minute or 5 minutes for each period; therefore, the change trend of each set period can be expressed through the first derivative mean value, when the change trend steadily rises, the cavitation suppression is judged to be needed, and the accuracy of the cavitation suppression can be improved in advance before cavitation occurs, so that the stable operation of the low-temperature liquid expander is ensured.
Preferably, the constructing cavitation target sequence based on cavitation data and pressure data includes: determining cavitation variation data based on cavitation degrees corresponding to the cavitation data or first derivative means of a plurality of corresponding set periods; comparing the pressure data with the output pressure range to determine pressure change data; and splicing the cavitation change data and the pressure change data to generate a cavitation target sequence.
When the cavitation degree corresponding to the real-time cavitation data exceeds a degree threshold, the difference value between the cavitation degree and the degree threshold can be used as cavitation change data, wherein the cavitation change data refers to the cavitation degree to be reduced; of course, cavitation variation data may also be greater than the difference. When the real-time cavitation degree is smaller than the degree threshold, and when the cavitation inhibition is needed due to the rising trend, taking the difference value between the current cavitation degree and the historical cavitation degree mean value as cavitation change data. The pressure change data refers to the output pressure of the cryogenic liquid expander, which must be within the output pressure range, and thus the pressure change data herein refers to the maximum change value (either the upper limit or the lower limit) of the output pressure.
The invention sets a cavitation target sequence which is the key for the subsequent screening of the model output result. And the cavitation target sequence is also a key for ensuring that the cavitation inhibition process does not influence the normal operation of the low-temperature liquid expander.
Preferably, the cavitation optimization model is constructed based on an artificial intelligence model, and comprises: setting a plurality of constraint condition sequences based on the restraint parameters, and simulating cavitation result sequences corresponding to the low-temperature liquid expansion machine in the plurality of constraint condition sequences; integrating a plurality of constraint condition sequences into standard input data, and integrating a plurality of corresponding cavitation result sequences into standard output data; and training the artificial intelligent model through the standard input data and the standard output data to obtain the cavitation optimization model.
The constraint condition sequence in the invention is consistent with the cavitation input data content attribute, and the cavitation result sequence is consistent with the cavitation target sequence content attribute; the artificial intelligence model includes a BP neural network model or an RBF neural network model. And constructing a mapping relation between the liquid type, the temperature change, the impeller rotating speed change and the liquid flow change, the output pressure and the cavitation degree through an artificial intelligent model. When cavitation inhibition is needed subsequently, the combination of the temperature change, the impeller rotating speed and the liquid flow rate can be determined according to the cavitation target sequence and the basic state data of the low-temperature liquid expander, and the efficiency and the application range of solving the mapping relation through the nonlinear capability of the artificial intelligent model are good.
Preferably, the setting a plurality of constraint condition sequences based on the constraint parameter includes: setting basic state data of the low-temperature liquid expander and setting a change step length of restraining constraint parameters; and combining the basic state data with a plurality of change step sizes to generate a plurality of constraint condition sequences.
A certain amount of simulated training data is required before training to obtain the cavitation optimization model. Setting basic state data of the low-temperature liquid expansion machine in different states, and setting a change step length of restraining constraint parameters. Splicing the basic state data with a plurality of variable step sizes of the restraint parameters to generate a restraint condition sequence; several constraint sequences can be generated by different combinations. It should be noted that the default liquid type is unchanged.
The constraint condition sequences set by the invention basically cover all working states of the low-temperature liquid expander, and the cavitation optimization model established based on a plurality of constraint condition sequences and corresponding cavitation result sequences has wider application range; the cavitation result sequence is the cavitation degree change condition and the output pressure change condition corresponding to the constraint condition sequence.
Preferably, the screening of the model output result through the cavitation target sequence includes: based on whether the cavitation target sequence can be met, integrating the model output result to obtain a cavitation suppression range; and selecting the temperature change data, the flow change data and the rotation speed change data with the lowest energy consumption from the cavitation inhibition range to be combined and spliced into a cavitation inhibition sequence.
The cavitation inhibition range comprises a temperature variation range, a flow variation range and a rotating speed variation range, namely, the cavitation inhibition control is carried out by selecting one value in the temperature variation range, the flow variation range and the rotating speed variation range, so that the cavitation target sequence requirement can be met, namely, the cavitation degree is reduced, and the output pressure is ensured to meet the requirement.
The invention further evaluates the energy consumption required by the process of adjusting each parameter to obtain the model output result with the lowest energy consumption as a cavitation suppression sequence, thereby realizing effective vortex cavitation suppression under low energy consumption.
Compared with the prior art, the invention has the beneficial effects that: judging whether cavitation inhibition is needed according to cavitation data or by combining cavitation data collected in history; combining the mapping relation between the restraint parameters, the cavitation degree and the pressure data change, identifying a cavitation restraint range capable of restraining cavitation and guaranteeing the working state of the low-temperature liquid expander, then combining the energy consumption of the control process to screen out a proper cavitation restraint sequence from the cavitation restraint range, and controlling the low-temperature liquid expander according to the cavitation restraint sequence to finish cavitation restraint; the invention can ensure the output pressure of the low-temperature liquid expander and simultaneously inhibit the output pressure effectively.
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In order to more clearly illustrate the embodiments of the invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, it being obvious that the drawings in the following description are only some embodiments of the invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a schematic diagram of the system principle of the present invention;
FIG. 2 is a schematic diagram of the method steps of the present invention.
Detailed Description
The technical solutions of the present invention will be clearly and completely described in connection with the embodiments, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
Referring to fig. 1-2, an embodiment of the present invention provides a control system for vortex cavitation flow in a low-temperature liquid expander, including a central control module, and a data acquisition module and an execution control module connected with the central control module; the data acquisition module is connected with a data sensor arranged in the low-temperature liquid expander; the data sensor comprises a cavitation monitor, a flow sensor, a temperature sensor and a rotating speed sensor; a central control module: monitoring cavitation data in the low-temperature liquid expander through a cavitation monitor connected with the data acquisition module; judging whether cavitation suppression is carried out or not based on the monitored cavitation data; if yes, cavitation inhibition is carried out; if not, continuously analyzing cavitation data; and constructing a cavitation target sequence based on the cavitation data and the pressure data; constructing cavitation input data according to the restraint parameters, inputting the cavitation input data into a cavitation optimization model, and screening model output results through a cavitation target sequence to obtain a cavitation restraint sequence; and the control execution control module performs cavitation suppression on the low-temperature liquid expander according to the cavitation suppression sequence.
The first step of this embodiment is to monitor cavitation data in the cryogenic liquid expander by a cavitation monitor connected to the data acquisition module; and judging whether cavitation suppression is carried out or not based on the monitored cavitation data.
Real-time cavitation data are acquired through a cavitation monitor arranged in the low-temperature liquid expander, and the cavitation data are converted into corresponding cavitation degrees according to the conversion relation between the cavitation data and the cavitation degrees. And judging whether the cavitation degree is larger than a set degree threshold value, and if so, judging that cavitation suppression is needed. The conversion relationship between cavitation data and cavitation degree can be referred to as kc=α×ks, where KC is the cavitation degree (which can be expressed as a fraction in a percentile), α is the conversion coefficient obtained by fitting, and KS is the monitored cavitation data.
When the cavitation degree is less than or equal to the set degree threshold, further analysis of the change trend of cavitation data is required, such as: extracting cavitation data acquired before, converting the cavitation data into a plurality of cavitation degrees related to time, and obtaining a cavitation change curve by taking time as an independent variable and taking the cavitation degrees as dependent variables in a fitting way; the cavitation change curve is corresponding to a range in time, the range is divided into a plurality of set periods according to the time step of 1 minute, if the range is 0-5, the set periods are [0,1], [1,2], [2,3], [3,4] and [4,5], a plurality of period moments can be uniformly set in each set period, and the first derivative mean value of the period moments is calculated as the period characteristic of the set period; when the cycle characteristics of a plurality of set cycles show an ascending trend, judging that cavitation suppression is needed; of course, the first derivative function of the cavitation curve may be integrated by an integration method over a set period, and the integrated value may be used as a period characteristic.
It should be noted that, judging that the cycle characteristics of the set cycles show an ascending trend, the cycle characteristics may be fitted into a straight line, and whether the ascending trend is determined according to the slope of the straight line.
The second step of this embodiment is to construct cavitation target sequences based on cavitation data and pressure data; constructing cavitation input data according to the restraint parameters, inputting the cavitation input data into a cavitation optimization model, and screening model output results through a cavitation target sequence to obtain a cavitation restraint sequence; and the control execution control module performs cavitation suppression on the low-temperature liquid expander according to the cavitation suppression sequence.
The premise of performing cavitation suppression is that it is necessary to know what degree of suppression is performed. When the cavitation level exceeds the level threshold, then the cavitation level needs to be reduced below the level threshold, so the cavitation variation data is minimized as the difference between the cavitation level and the level threshold. When the cavitation degree has an ascending trend, the difference between the current cavitation degree and the average value of the cavitation degrees of a plurality of set periods is used as cavitation change data.
The pressure change data is set to ensure that the output pressure meets the normal working requirement; if the current output pressure is within the defined pressure range, the pressure change data is the difference between the current output pressure and the lower limit of the pressure range. The cavitation change data and the pressure change data are used as cavitation target sequences, and are the basis for guaranteeing the completion of cavitation inhibition and the low-temperature liquid expansion machine.
Then, acquiring simulation training data, firstly setting a plurality of constraint condition sequences, wherein the constraint condition sequences are [ (YL, JW, JZ, JL), (JW, JZ, JL) ], YL is a liquid type, JW is a basic temperature in low-temperature liquid, JZ is a current impeller rotating speed, and JL is a liquid flow; JW, JZ, JL are temperature change, rotation speed change and flow change respectively, and JW, JZ, JL are integer multiples of a plurality of change step sizes. If the step of the change of the temperature is 1, JW can be 1 or-1.
According to the method, a plurality of constraint condition sequences can be obtained, cavitation result sequences of the low-temperature liquid expansion machine under the constraint condition sequences are simulated, a specific simulation process can be simplified to firstly adjust the low-temperature liquid expansion machine according to basic state data (YL, JW, JZ, JL), then adjust the low-temperature liquid expansion machine according to (JW, JZ and JL), the cavitation degree after adjustment is compared with the cavitation degree corresponding to the basic state data, the cavitation degree change condition is determined, and the output pressure change condition can be obtained through a similar scheme.
And training the artificial intelligent model through a plurality of constraint condition sequences and cavitation result sequences to obtain a cavitation optimization model. When cavitation suppression is needed, the basic state data of the current low-temperature liquid expander is determined, standard input data is obtained by combining the set change step length, and then corresponding model output data is obtained.
If the model output result does not meet the requirement of the cavitation target sequence, the model output result is screened through the cavitation target sequence, and the temperature, the rotating speed and the flow are regulated in which range, so that the stable operation of the low-temperature liquid expander can be ensured, and the cavitation inhibition can be realized.
And then, an equation is established by taking the variation amplitude of the temperature, the rotation speed and the flow as independent variables and the energy consumption as dependent variables, the corresponding temperature, the rotation speed and the flow combination when the equation takes the minimum value is solved, and when the combination is respectively in the corresponding temperature variation range, the flow variation range and the rotation speed variation range, the combination can be determined as a cavitation target sequence. The low-temperature liquid expander is controlled according to the cavitation target sequence, so that the aim of cavitation inhibition can be achieved.
When the low-temperature liquid expander is controlled according to the cavitation target sequence, and the cavitation inhibition effect achieved does not reach the target value, the actual cavitation target sequence, the corresponding cavitation data and pressure data are integrated into standard input data and standard output data, and the cavitation optimization model is trained and updated.
The partial data in the formula is obtained by removing dimension and taking the numerical value for calculation, and the formula is obtained by simulating a large amount of acquired data through software and is closest to the real situation; the preset parameters and the preset threshold values in the formula are set by those skilled in the art according to actual conditions or are obtained through mass data simulation.
The working principle of the invention is as follows: monitoring cavitation data in the low-temperature liquid expander through a cavitation monitor connected with the data acquisition module; judging whether cavitation suppression is carried out or not based on the monitored cavitation data; if yes, cavitation inhibition is carried out; if not, the cavitation data is continuously analyzed. Constructing a cavitation target sequence based on cavitation data and pressure data; constructing cavitation input data according to the restraint parameters, inputting the cavitation input data into a cavitation optimization model, and screening model output results through a cavitation target sequence to obtain a cavitation restraint sequence; and performing cavitation suppression on the low-temperature liquid expander according to the cavitation suppression sequence.
The above embodiments are only for illustrating the technical method of the present invention and not for limiting the same, and it should be understood by those skilled in the art that the technical method of the present invention may be modified or substituted without departing from the spirit and scope of the technical method of the present invention.
Claims (8)
1. A control system for vortex cavitation flow in a low-temperature liquid expander comprises a central control module, a data acquisition module and an execution control module, wherein the data acquisition module and the execution control module are connected with the central control module; the data acquisition module is connected with a data sensor arranged in the low-temperature liquid expander; the data sensor comprises a cavitation monitor, a flow sensor, a temperature sensor and a rotating speed sensor; the method is characterized in that:
a central control module: monitoring cavitation data in the low-temperature liquid expander through a cavitation monitor connected with the data acquisition module; judging whether cavitation suppression is carried out or not based on the monitored cavitation data; if yes, cavitation inhibition is carried out; if not, continuously analyzing cavitation data; the method comprises the steps of,
constructing a cavitation target sequence based on cavitation data and pressure data; constructing cavitation input data according to the restraint parameters, inputting the cavitation input data into a cavitation optimization model, and screening model output results through a cavitation target sequence to obtain a cavitation restraint sequence; the control execution control module performs cavitation suppression on the low-temperature liquid expander according to a cavitation suppression sequence; the restraining constraint parameters comprise rotation speed data, temperature data, flow data and liquid type, and the cavitation optimization model is constructed based on the artificial intelligence model.
2. The system for controlling vortex cavitation flow in a cryogenic liquid expander of claim 1, wherein the determining whether cavitation suppression is performed based on the monitored cavitation data comprises:
extracting the monitored cavitation data, and converting the cavitation data into cavitation degrees; judging whether the cavitation degree is larger than a set degree threshold value; if yes, cavitation inhibition is carried out; if not, continuously collecting cavitation data; or,
constructing a cavitation variation curve based on the monitored cavitation data, and judging whether cavitation inhibition is needed or not based on the variation trend of the cavitation variation curve; the cavitation change curve takes time as an independent variable.
3. The system according to claim 2, wherein the determining whether cavitation suppression is required based on the trend of the cavitation variation curve comprises:
setting a plurality of setting periods according to the independent variable value range of the cavitation variation curve, and uniformly determining a plurality of period moments in each setting period; calculating a first derivative value of each period moment based on the cavitation variation curve;
calculating the first derivative mean value of a plurality of period moments in the same set period; when the mean value of the first derivative corresponding to a plurality of set periods is in an ascending trend, cavitation suppression is carried out; otherwise, continuously analyzing the change trend.
4. A control system for vortex cavitation flow in a cryogenic liquid expander as claimed in claim 3 wherein the constructing cavitation target sequence based on cavitation data and pressure data comprises:
determining cavitation variation data based on cavitation degrees corresponding to the cavitation data or first derivative means of a plurality of corresponding set periods; wherein cavitation variation data refers to a degree of cavitation that needs to be reduced;
comparing the pressure data with the output pressure range to determine pressure change data; and splicing the cavitation change data and the pressure change data to generate a cavitation target sequence.
5. The control system for vortex cavitation flow in a cryogenic liquid expander of claim 1 or 4, wherein the cavitation optimization model is constructed based on an artificial intelligence model, comprising:
setting a plurality of constraint condition sequences based on the restraint parameters, and simulating cavitation result sequences corresponding to the low-temperature liquid expansion machine in the plurality of constraint condition sequences; the constraint condition sequence is consistent with the cavitation input data content attribute, and the cavitation result sequence is consistent with the cavitation target sequence content attribute;
integrating a plurality of constraint condition sequences into standard input data, and integrating a plurality of corresponding cavitation result sequences into standard output data; training an artificial intelligent model through standard input data and standard output data to obtain a cavitation optimization model; wherein the artificial intelligence model comprises a BP neural network model or an RBF neural network model.
6. The system for controlling vortex cavitation flow in a cryogenic liquid expansion machine of claim 5, wherein the setting of a plurality of constraint condition sequences based on the restraint parameters comprises:
setting basic state data of the low-temperature liquid expander and setting a change step length of restraining constraint parameters; the basic state data refer to rotating speed data, temperature data, flow data and liquid type during working;
and combining the basic state data with a plurality of change step sizes to generate a plurality of constraint condition sequences.
7. The system for controlling vortex cavitation flow in a cryogenic liquid expander of claim 6, wherein the screening of model output results by cavitation target sequences comprises:
based on whether the cavitation target sequence can be met, integrating the model output result to obtain a cavitation suppression range; the cavitation inhibition range comprises a temperature variation range, a flow variation range and a rotating speed variation range;
and selecting the temperature change data, the flow change data and the rotation speed change data with the lowest energy consumption from the cavitation inhibition range to be combined and spliced into a cavitation inhibition sequence.
8. The control system of vortex cavitation flow in a cryogenic liquid expander of claim 1, wherein the hub control module is in communication and/or electrical connection with the data acquisition module and the execution control module, respectively; the execution control module is used for controlling the low-temperature liquid expansion machine;
the data acquisition module is in communication and/or electrical connection with a data sensor arranged inside or outside the low-temperature liquid expander; and the data acquired by the data acquisition module is stored in the central control module.
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