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

Abstract

This invention relates to an automated data acquisition method and medium for a gas flow standard device using a sonic nozzle method, belonging to the field of flow metering technology. The method includes: real-time detection of the absolute stagnation pressure of the gas at the inlet of the calibrated sonic nozzle reaching a preset pressure point; 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; if both are stable, calculating the discharge coefficient of the calibrated sonic nozzle; and 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; if so, determining that the extended uncertainty technical index of the gas flow standard device is within a preset threshold range based on the stagnation pressure and stagnation temperature, and outputting the discharge coefficient of the calibrated sonic nozzle and its corresponding acquired data as the acquired data. This improves the stability of gas flow measurement and the calculation results of the discharge coefficient of the calibrated sonic nozzle.

Description

Technical Field

[0001] This invention relates to the field of flow metering technology, specifically to an automated data acquisition method and medium for a gas flow standard device using a sonic nozzle method. Background Technology

[0002] The stability analysis method for the gas flow standard device system using the sonic nozzle method is applied to the calibration of sonic nozzles using this standard device. In the calibration experiment of the sonic nozzle being calibrated, the discharge coefficient needs to be calibrated at multiple different flow points within the calibrated flow range. Furthermore, the calibration flow range differs for sonic nozzles with different throat diameters; therefore, the experimental conditions need to be changed multiple times throughout the calibration experiment.

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

[0004] Two crucial parameters affecting the high-precision measurement of gas flow rate and discharge coefficient are temperature and pressure. High-precision temperature and pressure measurements rely on stability and uncertainty assessment as their standards. In actual measurement processes, many factors influence the accuracy of the results; therefore, measurement uncertainty is typically a combination of the uncertainty components corresponding to these influencing factors. Regardless of the cause of the uncertainty component, each uncertainty factor can be evaluated in two ways: Type A uncertainty assessment and Type B uncertainty assessment. For quantities measured under specified conditions, the assessment uses statistical analysis methods, known as Type A measurement uncertainty assessment. Other components are assessed not through statistical analysis of observed data, but based on experience, manuals, certificates, or other information; this is known as Type B measurement uncertainty assessment.

[0005] However, in current calibration experiments, due to the instability of the gas supply system, it is difficult to obtain the gas flow rate and the discharge coefficient of the calibrated sonic nozzle under stable temperature and pressure measurements, resulting in poor stability of the gas flow rate measurement and the discharge coefficient of the calibrated sonic nozzle. Summary of the Invention

[0006] The technical problem to be solved by this application is to provide an automated data acquisition method and medium for a gas flow standard device using the sonic nozzle method, which has the characteristics of improving the stability of gas flow measurement and the calculation results of the discharge coefficient of the calibrated sonic nozzle.

[0007] In a first aspect, one embodiment provides an automated data acquisition method for a sonic nozzle method gas flow standard device, comprising:

[0008] Obtain the preset pressure of the current pressure point of the sonic nozzle being calibrated;

[0009] 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.

[0010] Calculate the ideal mass flow rate of the calibrated sonic nozzle under stable pressure and temperature conditions.

[0011] 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.

[0012] 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.

[0013] In one embodiment, determining 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.

[0014] In one embodiment, 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.

[0015] In one embodiment, the step 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 outflow coefficient of the calibrated sonic nozzle includes:

[0016] 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.

[0017] In one embodiment, determining 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:

[0018] 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.

[0019] 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.

[0020] Secondly, in one embodiment, a computer-readable storage medium is provided, the medium storing a program that can be loaded by a processor and executed by any of the above embodiments of the automatic data acquisition method for the sonic nozzle gas flow standard device.

[0021] The beneficial effects of this invention are:

[0022] 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 using the peak-to-peak pressure and peak-to-peak temperature values ​​to determine whether the pressure and temperature are stable within any first preset threshold time period, a preliminary assessment of pressure and temperature stability can be made. By using the discharge coefficient of the calibrated sonic nozzle to determine 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, the discharge coefficient calibration of the calibrated sonic nozzle can be achieved to meet system stability requirements. By using the stable stagnation pressure and stagnation temperature, it can be determined whether the extended uncertainty technical indicators of the gas flow standard device are within the preset threshold range, ensuring that the discharge coefficient uncertainty requirement is met. Therefore, stability analysis of the sonic nozzle method gas flow standard device under various flow rates can be performed, providing reliable and compliant experimental data, thereby meeting the uncertainty assessment requirements of the device and improving the stability of gas flow measurement and discharge coefficient calculation results of the calibrated sonic nozzle. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the pressure time-domain variation curve according to an embodiment of this application;

[0024] Figure 2This is a schematic diagram of the temperature time-domain variation curve according to an embodiment of this application;

[0025] Figure 3 This is a schematic flowchart of an embodiment of the automated data acquisition method for a gas flow standard device using a sonic nozzle method according to this application.

[0026] Figure 4 This is a schematic diagram of the time-domain variation curve of the pressure peak value according to an embodiment of this application;

[0027] Figure 5 This is a schematic diagram of the time-domain variation curve of the temperature peak value according to an embodiment of this application. Detailed Implementation

[0028] The present invention will now be described in further detail with reference to specific embodiments and accompanying drawings. Similar elements in different embodiments are referred to by associated similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of this application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to this application are not shown or described in the specification. This is to avoid obscuring the core parts of this application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0029] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0030] The serial numbers assigned to components in this article, such as "first" and "second", are used only to distinguish the objects being described and have no sequential or technical meaning.

[0031] To facilitate the explanation of the inventive concept of this application, the following is a brief description of the gas flow measurement and the calculation technique for the discharge coefficient of the calibrated sonic nozzle.

[0032] The applicant discovered in the research that during the calibration experiment, each time the intake flow rate was changed through the gas supply system, the gas temperature and pressure at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array would change drastically before stabilizing. At the same time, due to the instability of the gas supply system, slight fluctuations would occur when the flow rate reached the measurement value, causing the pressure and temperature at the inlet of the calibrated sonic nozzle and the standard sonic nozzle array to change as well. As a result, the collected temperature and pressure data did not meet the stability requirements, and the calculated discharge coefficient of the calibrated sonic nozzle was inaccurate, with poor repeatability and stability, increasing the uncertainty of the standard device.

[0033] 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.

[0034] 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.

[0035] 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 outflow coefficient of the sonic nozzle being calibrated, the outflow 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 outflow 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.

[0036] 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.

[0037] 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:

[0038] Step S10: Obtain the preset pressure of the pressure point of the current sonic nozzle being calibrated.

[0039] Before each effective judgment of the data, first determine the preset pressure of the i-th pressure point. .

[0040] 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.

[0041] 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.

[0042] 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.

[0043] 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 less than or equal to 2000 Pa 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, but the temperature can be considered stable if the fluctuation amplitude is less than or equal to 0.3℃.

[0044] Therefore, in some embodiments, the first preset threshold is 60s, the second preset threshold is 2000Pa, and the third preset threshold is 0.3℃.

[0045] Step S30: Calculate the ideal mass flow rate of the calibrated sonic nozzle under stable pressure and temperature conditions.

[0046] In one embodiment, the ideal mass flow rate of the calibrated sonic nozzle can be expressed as:

[0047]

[0048] 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.

[0049] in, It was obtained through testing. R and M can both be obtained by looking up a table.

[0050] Step S40: Calculate the discharge coefficient of the calibrated sonic nozzle based on the ideal mass flow rate and the actual mass flow rate.

[0051] 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:

[0052]

[0053] 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.

[0054] 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:

[0055]

[0056] 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.

[0057] in, It was obtained through testing. It can be obtained by looking up a table.

[0058] Simplifying the above equation, we get:

[0059] .

[0060] 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.

[0061] 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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:

[0066] 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.

[0067] In one embodiment, step S100 can be represented as:

[0068]

[0069] 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.

[0070] In one embodiment, k can be equal to 2.

[0071] 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.

[0072] 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.

[0073] 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. .

[0074] 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.

[0075] 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 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 calibrated sonic nozzle have reached a stable state based on the discharge coefficient of the calibrated sonic nozzle, the discharge 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 discharge coefficient uncertainty 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 and improve the stability of gas flow measurement and the calculation results of the discharge coefficient of the calibrated sonic nozzle.

[0076] 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.

[0077] 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.

[0078] 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. A method for automatic data acquisition of a gas flow standard device by means of a sonic nozzle, characterized in that, include: Obtain the preset pressure at the pressure point of the currently calibrated sonic nozzle; 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 calibrated sonic nozzle, it is determined 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, 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 calibrated sonic nozzle and its corresponding collected data are output as collected data. 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: Determine whether 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. 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. 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.

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 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.

8. 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 7, the method for automated data acquisition of a gas flow standard device using a sonic nozzle.

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