Automatic data acquisition method for sonic nozzle method gas flow standard device and medium

Abstract

The invention relates to an automatic data acquisition method for a sonic nozzle method gas flow standard device and a medium, and relates to the technical field of flow measurement. The method comprises the steps that when it is detected in real time that gas absolute stagnation pressure at an inlet of a calibrated sonic nozzle reaches preset pressure of a pressure point, whether the pressure and the temperature in any first preset threshold time period are stable or not is judged based on a pressure peak-to-peak value and a temperature peak-to-peak value; when the standard sonic nozzle array and the calibrated sonic nozzle are stable, calculating the outflow coefficient of the calibrated sonic nozzle, and judging whether the stagnation pressure and stagnation temperature at the standard sonic nozzle array and the inlet of the calibrated sonic nozzle reach a stable state or not; if yes, when it is judged that the expansion uncertainty technical index of the gas flow standard device is within the preset threshold value range based on the stagnation pressure and the stagnation temperature, the outflow coefficient of the calibrated sonic nozzle and the corresponding collected data serve as the collected data to be output. Therefore, the stability of gas flow measurement and the calculation result of the outflow coefficient of the calibrated sonic nozzle is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of flow measurement, in particular to a data automatic acquisition method of a gas flow standard device based on the sonic nozzle method and a medium. BACKGROUND

[0002] The system stability analysis method of the gas flow standard device based on the sonic nozzle method is applied to calibrate the sonic nozzle using the standard device. In the calibration experiment of the calibrated sonic nozzle, the outflow coefficient calibration work of multiple different flow points needs to be performed on the flow range calibrated by the calibrated sonic nozzle, and the calibration flow range of the calibrated sonic nozzle with different throat diameters is different, so the experimental state needs to be changed for multiple times in the whole calibration experiment.

[0003] The structure of the gas flow calibration device based on the sonic nozzle method mainly includes: a calibrated sonic nozzle upstream pipeline, a calibrated sonic nozzle downstream pipeline, a transition section, a standard sonic nozzle upstream pipeline, a standard sonic nozzle downstream pipeline, a temperature measuring device, a pressure measuring device, and a rectifier, etc.

[0004] Two important parameters affecting the high-precision measurement of gas flow and outflow coefficient are temperature and pressure. The high-precision measurement of temperature and pressure takes stability and uncertainty evaluation as its standard. In the actual measurement process, many factors will affect the accuracy of the results, so the measurement uncertainty is usually a combination of the corresponding uncertainty components of the influencing factors. No matter what causes the uncertainty components, each uncertainty factor can be evaluated in two ways: A-type uncertainty evaluation and B-type uncertainty evaluation. The value measured under the specified measurement conditions is evaluated by statistical analysis, which is called A-type evaluation of measurement uncertainty; other components are not evaluated by statistical analysis of observation data, but are evaluated based on experience or manual certificates and other information, which is called B-type evaluation of measurement uncertainty.

[0005] However, in the current calibration experiment, due to the instability of the gas supply system, it is difficult to obtain the gas flow and the outflow coefficient of the calibrated sonic nozzle under the stable condition of temperature and pressure measurement, thereby resulting in poor stability of the gas flow measurement and the outflow coefficient of the calibrated sonic nozzle. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a data automatic acquisition method of a gas flow standard device based on the sonic nozzle method and a medium, which can improve the stability of the gas flow measurement and the calculation result of the outflow coefficient of the calibrated sonic nozzle.

[0007] In a first aspect, a data automatic acquisition method of a gas flow standard device based on the sonic nozzle method is provided in an embodiment, comprising: obtaining a preset pressure of a pressure point of a current calibrated sonic nozzle; detecting the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle in real time, and determining whether the absolute stagnation pressure of the gas reaches the preset pressure of the pressure point, if yes, determining whether the pressure and the temperature are stable within any first preset threshold time period based on the pressure peak-to-peak value and the temperature peak-to-peak value; in the case that the pressure and the temperature are both stable, calculating the ideal mass flow rate of the calibrated sonic nozzle; calculating the discharge coefficient of the calibrated sonic nozzle based on the ideal mass flow rate and the actual mass flow rate of the calibrated sonic nozzle; determining whether the stagnation pressure and the stagnation temperature at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array reach a stable state based on the discharge coefficient of the calibrated sonic nozzle, if yes, determining whether the expanded uncertainty technical index of the gas flow standard device is within a preset threshold range based on the stagnation pressure and the stagnation temperature of the stable state, if yes, outputting the discharge coefficient of the calibrated sonic nozzle and the corresponding collected data as the collected data.

[0008] In an embodiment, the determination of whether the absolute stagnation pressure of the gas reaches the preset pressure of the pressure point comprises: collecting the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle, and determining whether the difference between the collected absolute stagnation pressure of the gas and the preset pressure of the pressure point is within a preset error range, if yes, considering that the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle has reached the preset pressure of the pressure point.

[0009] In an embodiment, the determination of whether the pressure and the temperature are stable within any first preset threshold time period based on the pressure peak-to-peak value and the temperature peak-to-peak value comprises: determining whether the pressure peak-to-peak value is less than or equal to a second preset threshold and the temperature peak-to-peak value is less than or equal to a third preset threshold within any first preset threshold time period.

[0010] In an embodiment, the determination of whether the stagnation pressure and the stagnation temperature at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array reach a stable state based on the discharge coefficient of the calibrated sonic nozzle comprises: determining whether the product of the ratio of the stagnation pressure at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array and the ratio of the stagnation temperature at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array is less than a preset fourth threshold, if yes, considering that the stagnation pressure and the stagnation temperature at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array reach a stable state.

[0011] In an embodiment, the determination of whether the expanded uncertainty technical index of the gas flow standard device is within a preset threshold range based on the stagnation pressure and the stagnation temperature of the stable state comprises: calculating an expanded uncertainty technical index of the gas flow standard device based on the discharge coefficient of the calibrated sonic nozzle, the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle, the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle, the discharge coefficient of the standard sonic nozzle, the absolute stagnation pressure of the gas at the inlet of the standard sonic nozzle, and the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle; determining whether the expanded uncertainty technical index is less than or equal to a preset fourth threshold value, and if so, considering that the uncertainty technical index of the gas flow standard device is within the preset threshold value range.

[0012] In a second aspect, a computer readable storage medium is provided in an embodiment, and the medium stores a program which can be loaded by a processor and execute the gas flow standard device data automatic acquisition method of the supersonic nozzle method according to any one of the above embodiments.

[0013] The present application has the following beneficial effects: By determining whether the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle reaches the preset pressure of the pressure point, it can be determined whether the pressure upstream of the standard sonic nozzle array reaches the preset pressure point, so that the pressure upstream of the standard sonic nozzle meets the pressure size of the upper traceability; by determining whether the pressure and temperature are stable in any first preset threshold time period through the pressure peak value and the temperature peak value, the stability of the pressure and temperature can be preliminarily determined; by determining whether the stagnation pressure and the stagnation temperature at the inlets of the standard sonic nozzle array and the calibrated sonic nozzle reach a stable state based on the discharge coefficient of the calibrated sonic nozzle, the discharge coefficient calibration of the calibrated sonic nozzle can be realized to meet the system stability requirement; by determining whether the expanded uncertainty technical index of the gas flow standard device is within the preset threshold value range based on the stagnation pressure and the stagnation temperature in the stable state, the discharge coefficient uncertainty size requirement can be met. In this way, the supersonic nozzle method gas flow standard device under multiple flow sizes can be analyzed for stability, reliable and required experimental data can be provided, so as to meet the uncertainty evaluation requirement of the device and improve the stability of the gas flow measurement and the calculation result of the discharge coefficient of the calibrated sonic nozzle. BRIEF DESCRIPTION OF DRAWINGS

[0014] Figure 1 is a pressure time domain variation curve schematic diagram of an embodiment of the present application; Figure 2 is a temperature time domain variation curve schematic diagram of an embodiment of the present application; Figure 3 is a supersonic nozzle method gas flow standard device data automatic acquisition method flowchart schematic diagram of an embodiment of the present application; Figure 4is a schematic diagram of a pressure peak-to-peak time-domain variation curve of an embodiment of the present application; Figure 5 is a schematic diagram of a temperature peak-to-peak time-domain variation curve of an embodiment of the present application. DETAILED DESCRIPTION

[0015] The application will be described in further detail below with specific reference to the drawings. Like elements in different embodiments are denoted by like reference numerals. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application. However, it will be apparent to one skilled in the art that some features, which are not necessarily the most important to implementation of the application, can be omitted or substituted for others in accordance with the disclosure. In some instances, detailed descriptions of structures and / or methods can be omitted or simplified for clarity.

[0016] In addition, the features, operations or characteristics described in the specification can be combined in any appropriate manner in various embodiments. Also, the order of the steps or acts in the method descriptions can be changed or adjusted as can be apparent to those skilled in the art. Therefore, the various sequences described in the specification and the accompanying drawings are merely exemplary and do not necessarily mean a mandatory sequence, unless otherwise specified.

[0017] The serial numbers of components in the text, such as "first", "second", etc., are only used to distinguish the described objects, and do not have any order or technical meaning.

[0018] In order to illustrate the inventive concept of the present application, the gas flow measurement and calibrated sonic nozzle discharge coefficient calculation technology are briefly described below.

[0019] The applicant found in the research that in the calibration experiment, after changing the size of the inlet flow of the gas supply system each time, the temperature and pressure of the gas at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array would change dramatically, and then recover to stable. At the same time, due to the instability of the gas supply system, when the flow reached the measured value, slight fluctuations would occur, which would cause the pressure and temperature at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array to change, resulting in that the temperature and pressure data collected did not meet the stability requirements, and thus the discharge coefficient of the calibrated sonic nozzle calculated was inaccurate, with poor repeatability and stability, and the uncertainty of the standard device was increased.

[0020] To clearly illustrate the scheme of this application, the calibration experiment of a sonic nozzle with a throat diameter of 8.251 mm is used as an example in this embodiment. In the calibration experiment, complete experimental data were collected for the five absolute stagnation pressure points (1.0 MPa, 2.5 MPa, 4.0 MPa, 5.0 MPa, 6.0 MPa) at the inlet of the sonic nozzle corresponding to the five flow rate points (0.12 kg / s, 0.30 kg / s, 0.44 kg / s, 0.60 kg / s, 0.75 kg / s), and the time-domain variation curves of pressure and temperature were plotted. Please refer to... Figure 1 The applicant discovered in their research that the pressure upstream of the sonic nozzle array increases sharply each time the gas flow rate changes, and then stabilizes as the flow rate stabilizes. Please refer to [reference needed]. Figure 2 Temperature also changes drastically with changes in flow rate. When the flow rate increases, the temperature rises sharply, then slowly decreases to roughly the temperature before the flow rate change once the flow rate stabilizes. After each flow rate change, the pressure takes approximately 240 seconds to stabilize, while the temperature takes much longer, approximately 360 seconds. Simultaneously, the temperature fluctuates dramatically with flow rate changes, with a maximum fluctuation amplitude of 10°C. This amplitude gradually decreases to 4°C after the flow rate increases. Furthermore, the absolute stagnation temperature of the gas at the inlet of the standard sonic nozzle array lags behind the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle by approximately 20 seconds.

[0021] The time-domain data analysis of pressure and temperature shows that after the calibration flow rate changes, it takes at least 360 seconds for the system to reach a steady state and for the pressure and temperature values ​​to stabilize. The main reason for this long time is that the temperature fluctuates sharply by up to 10°C after the calibration flow rate changes, requiring a long time to recover and stabilize.

[0022] In view of this, this application provides an automated data acquisition method and medium for a gas flow standard device using a sonic nozzle method. By determining whether the absolute stagnation pressure of the gas at the inlet of the sonic nozzle being calibrated reaches the preset pressure of the pressure point, it can be determined whether the upstream pressure of the standard sonic nozzle array has reached the preset pressure point, ensuring that the pressure upstream of the standard sonic nozzle is the same as the pressure during upstream tracing. By determining whether the pressure and temperature are stable within any first preset threshold time period using the peak-to-peak pressure and peak-to-peak temperature, a preliminary assessment of pressure and temperature stability can be made. By determining whether the stagnation pressure and stagnation temperature at the inlet of both the standard sonic nozzle array and the sonic nozzle being calibrated have reached a stable state based on the discharge coefficient of the sonic nozzle being calibrated, the discharge coefficient calibration of the sonic nozzle being calibrated can be achieved to meet system stability requirements. By determining whether the extended uncertainty technical indicators of the gas flow standard device are within the preset threshold range based on the stable stagnation pressure and stagnation temperature, the requirements for the uncertainty of the discharge coefficient can be met. This enables stability analysis of the gas flow standard device using the sonic nozzle method under various flow rates, providing reliable and compliant experimental data to meet the uncertainty assessment requirements of the device. It can effectively improve the stability of gas flow measurement and the calculation results of the discharge coefficient of the calibrated sonic nozzle.

[0023] The following section will take any one of the five pressure points mentioned above as an example to provide a detailed description of the solution in this application.

[0024] Please refer to Figure 3 This application provides an automated data acquisition method for a gas flow standard device using a sonic nozzle method, comprising: Step S10: Obtain the preset pressure of the pressure point of the current sonic nozzle being calibrated.

[0025] Before each effective judgment of the data, first determine the preset pressure of the i-th pressure point. .

[0026] Step S20: Real-time detection of the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle, and determination of whether the absolute stagnation pressure of the gas reaches the preset pressure of the pressure point. If so, determination of whether the pressure and temperature are stable within any first preset threshold time period based on the peak-to-peak pressure and peak-to-peak temperature.

[0027] Since the gas supply system of the gas flow standard device can control the absolute stagnation pressure error of the gas at the inlet of the calibrated sonic nozzle within a certain range, in one embodiment of this application, the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle is collected, and it is determined whether the difference between the collected absolute stagnation pressure and the preset pressure of the pressure point is within the preset error range (e.g., 0.1 MPa). If so, it is considered that the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle has reached the preset pressure of the pressure point.

[0028] In one embodiment, the stability of pressure and temperature within any first preset threshold time period is determined by judging whether the peak value of pressure is less than or equal to a second preset threshold and whether the peak value of temperature is less than or equal to a third preset threshold within any first preset threshold time period.

[0029] Please refer to Figure 4 After the pressure point stabilizes, the maximum peak-to-peak value of the 60-second data is 2000 Pa. While the instability of the gas supply system does affect pressure fluctuations in steady state, a fluctuation amplitude of 2000 Pa or less can be considered a stable pressure. Please refer to [reference needed]. Figure 5 After the temperature reaches a steady state, the peak-to-peak value of the 60-second data is 0.3℃. Due to the instability of the gas supply system, the frequency of temperature fluctuations is greater than that of pressure fluctuations. However, the temperature can be considered stable if the fluctuation amplitude is less than or equal to 0.3℃.

[0030] Therefore, in some embodiments, the first preset threshold is 60s, the second preset threshold is 2000Pa, and the third preset threshold is 0.3℃.

[0031] Step S30: Calculate the ideal mass flow rate of the calibrated sonic nozzle under stable pressure and temperature conditions.

[0032] In one embodiment, the ideal mass flow rate of the calibrated sonic nozzle can be expressed as: in, This represents the ideal mass flow rate at the i-th pressure point of the calibrated sonic nozzle. This indicates the cross-sectional area of ​​the throat of the sonic nozzle being calibrated. Let represent the actual gas critical flow function of the calibrated sonic nozzle at the i-th pressure point. This represents the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point. R represents the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point, R represents the universal gas constant, and M represents the molecular weight of the gas.

[0033] in, It was obtained through testing. R and M can both be obtained by looking up a table.

[0034] Step S40: Calculate the discharge coefficient of the calibrated sonic nozzle based on the ideal mass flow rate and the actual mass flow rate.

[0035] Because actual conditions differ from ideal conditions, the actual flow rate of the sonic nozzle differs from the ideal mass flow rate. The relationship between them can be established using the discharge coefficient. Therefore, in one embodiment, step S40 can be expressed as: in, This represents the discharge coefficient of the calibrated sonic nozzle at the i-th pressure point. This represents the actual mass flow rate of the calibrated sonic nozzle at the i-th pressure point.

[0036] Due to the principle that the gas flow rate through the sonic nozzle gas flow standard device is constant, the actual gas mass flow rate is measured by the standard sonic nozzle array. The calculation formula for the actual gas mass flow rate measured by the standard sonic nozzle array is the same as that for the sonic nozzle, where the discharge coefficient of the standard sonic nozzle array at the i-th pressure point is... The source is known from the higher-level tracing. Therefore, the formula for calculating the outflow coefficient of the calibrated sonic nozzle can be expanded as follows: in, This represents the cross-sectional area of ​​the throat of a standard sonic nozzle. This represents the actual gas critical flow function of the standard sonic nozzle at the i-th pressure point. Let represent the absolute stagnation pressure of the gas at the inlet of the standard sonic nozzle at the i-th pressure point. The absolute stagnation temperature of the gas at the inlet of the standard sonic nozzle at the i-th pressure point is represented by . This represents the outflow coefficient of the standard sonic nozzle array at the i-th pressure point.

[0037] in, It was obtained through testing. It can be obtained by looking up a table.

[0038] Simplifying the above equation, we get: .

[0039] The stagnation pressure and stagnation temperature at the inlet of the standard sonic nozzle array lag behind those of the calibrated sonic nozzle. A single analysis of the stability of the stagnation pressure and stagnation temperature does not indicate that the system has reached a stable state. Therefore, it is necessary to observe the stagnation pressure and stagnation temperature at both ends simultaneously.

[0040] Step S50: Based on the outflow coefficient of the calibrated sonic nozzle, determine whether the stagnation pressure and stagnation temperature at the inlet of the standard sonic nozzle array and the calibrated sonic nozzle have both reached a stable state. If so, based on the stagnation pressure and stagnation temperature of the stable state, determine whether the extended uncertainty technical index of the gas flow standard device is within a preset threshold range. If it is within the preset threshold range, output the outflow coefficient of the calibrated sonic nozzle as the collected data.

[0041] Based on the simplified outflow coefficient above The calculation formula, because , and Since both are constants, we only need to make a time-domain stability judgment on the variable that is the product of the ratio of stagnation pressure and the ratio of stagnation temperature.

[0042] Therefore, in one embodiment, determining whether the stagnation pressure and stagnation temperature at the inlet of the standard sonic nozzle array and the calibrated sonic nozzle have both reached a stable state based on the outflow coefficient of the calibrated sonic nozzle includes: determining whether the product of the ratio of the stagnation pressure at the inlet of the standard sonic nozzle array and the ratio of the stagnation temperature at the inlet of the calibrated sonic nozzle is less than a preset fourth threshold; if so, it is considered that the stagnation pressure and stagnation temperature at the inlet of the standard sonic nozzle array and the calibrated sonic nozzle have both reached a stable state.

[0043] The fourth threshold can be set based on practical experience. For example, in one embodiment of this application, the fourth threshold can be set to 0.0045, that is, when the peak-to-peak value of the product of the ratio of stagnation pressure and the ratio of stagnation temperature is less than 0.0045, it is considered that the stagnation pressure and stagnation temperature at the inlet of the standard sonic nozzle array and the calibrated sonic nozzle have reached a stable state.

[0044] In one embodiment, based on the stagnation pressure and stagnation temperature of the steady state, determining whether the extended uncertainty technical indicators of the gas flow rate standard device are within a preset threshold range includes: Step S100: Based on the discharge coefficient of the calibrated sonic nozzle at the i-th pressure point, the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle, the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle, the discharge coefficient of the standard sonic nozzle, the absolute stagnation pressure of the gas at the inlet of the standard sonic nozzle, and the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle, calculate the extended uncertainty technical parameters of the gas flow standard device.

[0045] In one embodiment, step S100 can be represented as: in, This represents the discharge coefficient of the calibrated sonic nozzle at the i-th pressure point. This represents the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point. This represents the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point. This represents the discharge coefficient of the standard sonic nozzle at the i-th pressure point. This represents the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point. The absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point is represented. Indicates extended uncertainty technical indicators, This represents an uncertain technical indicator function, where k represents the expansion coefficient.

[0046] In one embodiment, k can be equal to 2.

[0047] Uncertainty technical indicator functions can be expressed as: Where n represents the index of the sampling point, a represents the sampling data, and N represents the number of sampling points, 1 ≤ n ≤ N. This represents the value of the nth sampled data. This represents the average value of the sampled data.

[0048] Step S200: Determine whether the extended uncertain technical index is less than or equal to the preset fourth threshold. If so, it is considered that the uncertain technical index of the gas flow standard device is within the preset threshold range.

[0049] In some embodiments, in order to meet the requirements when collecting valid data The uncertainty requirement is to analyze and judge the data every 60 seconds. In order to satisfy The uncertainty requirement is to analyze and judge the data every 60 seconds. .

[0050] Once all the above judgment conditions are met, the collected 60s data is considered to be valid data, satisfying the requirements for outflow coefficient and expanded uncertainty.

[0051] Based on the above scheme, by determining whether the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle reaches the preset pressure of the pressure point, it can be determined whether the upstream pressure of the standard sonic nozzle array reaches the preset pressure point, ensuring that the pressure upstream of the standard sonic nozzle is the same as the pressure during upstream tracing. By determining whether the pressure and temperature are stable within any first preset threshold time period through the peak-to-peak pressure and peak-to-peak temperature, a preliminary assessment of pressure and temperature stability can be made. By determining whether the stagnation pressure and stagnation temperature at the inlet of both the standard sonic nozzle array and the calibrated sonic nozzle have reached a stable state based on the outflow coefficient of the calibrated sonic nozzle, the outflow coefficient calibration of the calibrated sonic nozzle can be achieved to meet system stability requirements. By determining whether the extended uncertainty technical indicators of the gas flow standard device are within the preset threshold range based on the stable stagnation pressure and stagnation temperature, the requirements for the magnitude of the outflow coefficient uncertainty can be met. This enables stability analysis of the sonic nozzle gas flow standard device under various flow rates, providing reliable and compliant experimental data to meet the uncertainty assessment requirements of the device and improve the stability of gas flow measurement and the calculation results of the discharge coefficient of the calibrated sonic nozzle.

[0052] One embodiment of this application provides a computer-readable storage medium storing a program, the stored program including methods that can be loaded by a processor and processed in any of the above embodiments.

[0053] Those skilled in the art will understand that all or part of the functions of the various methods in the above embodiments can be implemented by hardware or by computer programs. When all or part of the functions in the above embodiments are implemented by computer programs, the program can be stored in a computer-readable storage medium, which may include: read-only memory, random access memory, disk, optical disk, hard disk, etc., and the program is executed by a computer to achieve the above functions. For example, the program can be stored in the memory of a device, and when the program in the memory is executed by the processor, all or part of the above functions can be achieved. In addition, when all or part of the functions in the above embodiments are implemented by computer programs, the program can also be stored in a server, another computer, disk, optical disk, flash drive, or external hard drive, etc., and can be downloaded or copied to the memory of a local device, or the system of the local device can be updated. When the program in the memory is executed by the processor, all or part of the functions in the above embodiments can be achieved.

[0054] The above examples illustrate the present invention only to aid in understanding it and are not intended to limit the scope of the invention. Those skilled in the art can make various simple deductions, modifications, or substitutions based on the principles of this invention.

Claims

1. An automated data acquisition method for a gas flow standard device using a sonic nozzle method, characterized in that, include: Obtain the preset pressure of the current pressure point of the sonic nozzle being calibrated; The absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle is detected in real time, and it is determined whether the absolute stagnation pressure of the gas reaches the preset pressure of the pressure point. If so, it is determined whether the pressure and temperature are stable within any first preset threshold time period based on the peak-to-peak pressure and peak-to-peak temperature. Calculate the ideal mass flow rate of the calibrated sonic nozzle under stable pressure and temperature conditions. The discharge coefficient of the calibrated sonic nozzle is calculated based on the ideal mass flow rate and the actual mass flow rate of the calibrated sonic nozzle. Based on the outflow coefficient of the sonic nozzle being calibrated, it is determined whether the stagnation pressure and stagnation temperature at the inlet of both the standard sonic nozzle array and the sonic nozzle being calibrated have reached a stable state. If so, based on the stagnation pressure and stagnation temperature of the stable state, it is determined whether the extended uncertainty technical index of the gas flow standard device is within a preset threshold range. If it is within the preset threshold range, the outflow coefficient of the sonic nozzle being calibrated and its corresponding collected data are output as collected data.

2. The automated data acquisition method for the sonic nozzle method gas flow standard device as described in claim 1, characterized in that, The determination of whether the absolute stagnation pressure of the gas has reached the preset pressure of the pressure point includes: collecting the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle, determining whether the difference between the collected absolute stagnation pressure of the gas and the preset pressure of the pressure point is within a preset error range, and if so, considering that the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle has reached the preset pressure of the pressure point.

3. The automated data acquisition method for the sonic nozzle method gas flow standard device as described in claim 1, characterized in that, The method of determining whether the pressure and temperature are stable within any first preset threshold time period based on the peak-to-peak pressure and peak-to-peak temperature includes: determining whether the peak-to-peak pressure is less than or equal to a second preset threshold and whether the peak-to-peak temperature is less than or equal to a third preset threshold within any first preset threshold time period.

4. The automated data acquisition method for the sonic nozzle method gas flow standard device as described in claim 3, characterized in that, The first preset threshold is 60s, and / or the second preset threshold is 2000Pa, and / or the third preset threshold is 0.3℃.

5. The automated data acquisition method for the sonic nozzle method gas flow standard device as described in claim 1, characterized in that, The calculation of the ideal mass flow rate of the calibrated sonic nozzle includes: in, This represents the ideal mass flow rate at the i-th pressure point of the calibrated sonic nozzle. This indicates the cross-sectional area of ​​the throat of the sonic nozzle being calibrated. Let represent the actual gas critical flow function of the calibrated sonic nozzle at the i-th pressure point. This represents the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point. R represents the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point, R represents the universal gas constant, and M represents the molecular weight of the gas.

6. The automated data acquisition method for the sonic nozzle method gas flow standard device as described in claim 5, characterized in that, The calculation of the discharge coefficient of the sonic nozzle under calibration based on the ideal mass flow rate and the actual mass flow rate includes: in, This represents the discharge coefficient of the calibrated sonic nozzle at the i-th pressure point. This represents the actual mass flow rate of the calibrated sonic nozzle at the i-th pressure point.

7. The automated data acquisition method for the sonic nozzle method gas flow standard device as described in claim 1, characterized in that, The method of determining whether the stagnation pressure and stagnation temperature at the inlet of both the standard sonic nozzle array and the calibrated sonic nozzle have reached a stable state based on the discharge coefficient of the calibrated sonic nozzle includes: If the product of the ratio of stagnation pressure at the inlet of the standard sonic nozzle array and the ratio of stagnation temperature at the inlet of the calibrated sonic nozzle is less than a preset fourth threshold, then it is considered that the stagnation pressure and stagnation temperature at the inlet of both the standard sonic nozzle array and the calibrated sonic nozzle have reached a stable state.

8. The automated data acquisition method for the sonic nozzle method gas flow standard device as described in claim 1, characterized in that, The determination of whether the extended uncertainty technical indicators of the gas flow rate standard device are within a preset threshold range based on the stagnation pressure and stagnation temperature of the steady state includes: Based on the discharge coefficient of the calibrated sonic nozzle at the i-th pressure point, the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle, the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle, the discharge coefficient of the standard sonic nozzle, the absolute stagnation pressure of the gas at the inlet of the standard sonic nozzle, and the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle, calculate the extended uncertainty technical indicators of the gas flow standard device. Determine whether the extended uncertainty technical indicator is less than or equal to a preset fourth threshold. If so, the uncertainty technical indicator of the gas flow standard device is considered to be within the preset threshold range.

9. The automated data acquisition method for the sonic nozzle method gas flow standard device as described in claim 8, characterized in that, The extended uncertainty technical specifications of the aforementioned gas flow rate calculation standard device include: in, This represents the discharge coefficient of the calibrated sonic nozzle at the i-th pressure point. This represents the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point. This represents the absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point. This represents the discharge coefficient of the standard sonic nozzle at the i-th pressure point. This represents the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point. The absolute stagnation temperature of the gas at the inlet of the calibrated sonic nozzle at the i-th pressure point is represented. Indicates extended uncertainty technical indicators, This represents an uncertain technical indicator function, where k represents the expansion coefficient.

10. A computer-readable storage medium, characterized in that, The medium stores a program that can be loaded by a processor and executed as described in any one of claims 1 to 9, the method for automated data acquisition of a gas flow standard device using a sonic nozzle.

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