Low-pressure wind speed calibration optimization method and system

Abstract

The invention provides a low-pressure wind speed calibration optimization method and system, and the method comprises the steps: determining a to-be-simulated Reynolds number range according to the performance requirements and target environment conditions of a to-be-calibrated sensor; based on the determined Reynolds number range, an air duct capable of forming stable sinking jet flow is selected; calculating a peak gas flow required by calibration according to the determined Reynolds number range and the selected air duct; selecting an adaptive pressure maintaining system based on the peak gas flow; working condition parameter data of the current space simulation environment are obtained, environment parameter adjustment is carried out until the environment parameters are stable, and the environment parameter adjustment comprises the steps of calculating the volume flow of a nozzle and controlling the multiple environment parameters; and based on the adjusted environmental parameters, calibrating the sensor to be calibrated, and evaluating the calibrated data. According to the invention, the calibration error caused by the speed distribution of the calibration nozzle can be evaluated and corrected, and a more accurate calibration result is obtained.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of environmental testing, in particular to a low-pressure wind speed calibration optimization method and system. BACKGROUND

[0002] In order to verify deep space probes and high-altitude unmanned aerial vehicles operating at low air pressure, such as in ground tests of Mars probes and stratospheric unmanned aerial vehicles, the convection environment in which they are located needs to be simulated, i.e., the convection environment at-80℃ and around 1 kPa air pressure. However, wind speed sensors of various principles such as thermal, ultrasonic, and dynamic pressure measurement are difficult to measure pressures around 1 kPa, often with weak signals and easy to be disturbed. Special low-pressure wind speed sensors also often need to be recalibrated in this environment. Existing development systems often have difficulties in use and it is difficult to evaluate errors. Specifically, the error of the existing system often gradually accumulates with use, such as a rotating wind speed calibration system. As the calibration proceeds, the air will gradually generate streamwise, causing the original flow field speed to gradually increase, and the speed difference between the rotating arm and the flow field to gradually decrease, resulting in gradually increasing calibration error. This error cannot be measured by existing means, so it is difficult to evaluate. The Reynolds number is very low at low air pressure, often in a laminar state. Therefore, the calibration method using a wind tunnel often causes the problem of boundary layer separation, resulting in uneven wind speed distribution at the outlet. Due to the influence of Knudsen number at low air pressure, the characteristic length of the sensor cannot be too small, resulting in the characteristic length of the sensor relative to the area of the nozzle cannot be ignored, making it difficult to place the sensor at the center of the wind tunnel, i.e., the distribution characteristics of the wind speed will bring additional errors.

[0003] Therefore, it is necessary to provide a new low-pressure wind speed calibration optimization method and system to solve one of the above technical problems. SUMMARY

[0004] The purpose of the present application is to provide a low-pressure wind speed calibration optimization method and system that can solve at least one of the above technical problems. The specific scheme is as follows:

[0005] According to the specific embodiments of the present application, the present application provides a low air pressure wind speed calibration optimization method, comprising: determining a Reynolds number range to be simulated according to performance requirements and target environmental conditions of a sensor to be calibrated; selecting an air duct capable of forming a stable submerged jet based on the determined Reynolds number range; calculating a peak gas flow required for calibration according to the determined Reynolds number range and the selected air duct; selecting an adapted pressure maintaining system based on the peak gas flow; obtaining working condition parameter data of a current space simulation environment, adjusting environmental parameters until the environmental parameters are stable, wherein the adjusting of the environmental parameters comprises calculating a nozzle volume flow and controlling multiple environmental parameters; calibrating the sensor to be calibrated based on the adjusted environmental parameters, and evaluating the calibrated data.

[0006] According to the specific embodiments of the present application, the present application also provides a wind speed calibration optimization system, which performs the low air pressure wind speed calibration optimization method described in the present application, comprising: a space environment simulation container, a simulation air duct built in the space environment simulation container, a sensor to be calibrated, an air duct inlet pipeline connected to the space environment simulation container, a gas source, a heat exchanger between the gas source and the air duct inlet pipeline, and a pressure control system connected to the space environment simulation container.

[0007] According to the specific embodiments of the present application, the present application also provides a computer readable storage medium having a computer program stored thereon, wherein the program, when executed by a processor, implements the low air pressure wind speed calibration optimization method according to any one of the above.

[0008] According to the specific embodiments of the present application, the present application also provides an electronic device, comprising: one or more processors; a storage device configured to store one or more programs, wherein the one or more programs, when executed by the one or more processors, cause the one or more processors to implement the low air pressure wind speed calibration optimization method according to any one of the above.

[0009] The above-mentioned scheme of the embodiments of the present application has at least the following beneficial effects compared with the prior art:

[0010] The application is based on the continuous wind field formed by the internal and external pressure difference of the current space simulation environment, according to the performance requirements and target environment conditions of the sensor to be calibrated, the Reynolds number range to be simulated is determined, so as to select the air duct capable of forming stable submerged jet, according to the determined Reynolds number range and the selected air duct, the peak gas flow required for calibration is calculated, the pressure maintaining system suitable for the application can be accurately selected, and the pressure control accuracy can be improved; by obtaining the working condition parameter data of the current space simulation environment, the environment parameter is adjusted until the environment parameter is stable, based on the adjusted environment parameter, the sensor to be calibrated is calibrated, and more accurate calibration data can be obtained; by evaluating the calibrated data, the calibration error caused by the jet velocity distribution is evaluated and corrected, and more accurate calibration results can be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0011] The drawings incorporated into the specification and forming a part thereof, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the application. It is clear that the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained from these drawings without creative labor for those skilled in the art. In the drawings:

[0012] Figure 1 The flowchart of the low air pressure wind speed calibration optimization method of the embodiment of the present application;

[0013] Figure 2 The structural schematic diagram of an application example of the low air pressure wind speed calibration optimization method of the embodiment of the present application;

[0014] Figure 3 The jet velocity distribution schematic diagram obtained by applying the low air pressure wind speed calibration optimization method of the embodiment of the present application;

[0015] Figure 4 The matching schematic diagram of the jet volume flow and the air extraction process in the low air pressure wind speed calibration optimization method of the embodiment of the present application;

[0016] Figure 5 The schematic diagram of the relationship between the radius of the air duct jet and the wind speed in the low air pressure wind speed calibration optimization method of the embodiment of the present application;

[0017] Figure 6 The structural schematic diagram of the low air pressure wind speed calibration optimization system of the embodiment of the present application;

[0018] Figure 7 The structural schematic diagram of the electronic device shown in the embodiment of the present application. DETAILED DESCRIPTION

[0019] In order to make the purposes, technical solutions and advantages of the present application clearer, the following further describes the present application with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of the present application.

[0020] The terms used in the embodiments of the present application are only for the purpose of describing particular embodiments and are not intended to limit the present application. The singular forms "a", "an" and "the" used in the embodiments of the present application and the appended claims are also intended to include the plural forms, unless the context clearly indicates otherwise. "Plural" generally includes at least two.

[0021] It should be understood that the term "and / or" used herein only describes an association relationship of associated objects, which means that there can be three relationships, for example, A and / or B can mean that A exists alone, A and B exist together, and B exists alone. In addition, the character " / " herein generally represents that the front and rear associated objects are in an "or" relationship.

[0022] It should be understood that although the terms first, second, third, etc. can be used in the embodiments of the present application to describe, these descriptions should not be limited to these terms. These terms are only used to distinguish the description. For example, without departing from the scope of the embodiments of the present application, the first can also be called the second, and similarly, the second can also be called the first.

[0023] It should also be noted that the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusion, so that the products or devices including a series of elements not only include those elements, but also include other elements not explicitly listed, or further include elements inherent to such products or devices. Without more limitations, the element defined by the sentence "including a" does not exclude the presence of other identical elements in the product or device including the element.

[0024] This application provides a low-pressure wind speed calibration optimization method. The method determines the Reynolds number range to be simulated based on the performance requirements of the sensor to be calibrated and the target environmental conditions, in order to select a wind duct that can form a stable submerged jet. Based on the determined Reynolds number range and the selected wind duct, the peak gas flow rate required for calibration is calculated. Based on the peak gas flow rate, a suitable pressure control component in the pressure maintenance system is selected to accurately control and acquire the operating parameter data of the current space simulation environment. Environmental parameters are adjusted until they stabilize. This environmental parameter adjustment includes calculating the nozzle volumetric flow rate and controlling multiple environmental parameters. Based on the adjusted environmental parameters, the sensor to be calibrated is calibrated to obtain more accurate calibration results. By evaluating the calibrated data and assessing and correcting the calibration error caused by the nozzle velocity distribution, even more accurate calibration results can be obtained.

[0025] It should be noted that this application uses the simulated pressure difference inside and outside the duct as the wind speed driving method, and the flow meter on the outside of the space environment simulation container as the mass flow rate, i.e., the wind speed, as the reference. It actively collects and records the wind speed signal distribution at the duct nozzle (or duct nozzle) by moving the sensor to be calibrated (e.g., a wind speed sensor). The wind speed at the duct nozzle is calculated using the calibration data and compared and iterated with reference data (i.e., theoretical data) to accurately calibrate the sensor to be calibrated, thereby solving the problem of difficulty in assessing the velocity error of the calibrated duct nozzle. Furthermore, the method of this application has wide applications, especially suitable for wind speed sensor calibration in low-pressure, low-Reynolds-number environments, where low pressure is generally 500 Pa to 10000 Pa. The low Reynolds number, calculated based on the characteristic length of the duct (outlet diameter), is approximately in the thousands to tens of thousands. In addition, the method of this application is particularly suitable for application scenarios such as Mars rovers and low-speed stratospheric vehicles. In ground verification of Mars probes and stratospheric spacecraft, it is usually necessary to simulate the extreme convective environments faced by the probes and spacecraft. Before the ground simulation test, the wind speed sensor, i.e., the sensor to be calibrated, can be calibrated more accurately and effectively, so that the calibrated wind speed sensor can effectively measure wind speed under low-pressure environments (700 Pa in the Martian environment, and 5500 Pa in a typical 20km stratosphere environment) in the ground simulation test. The following is a specific example based on the low Reynolds number of the flow on a certain object surface (e.g., the Reynolds number is as low as 4000 in the range of the wind tunnel nozzle).

[0026] The following is in conjunction with the appendix Figures 1 to 5 Detailed description of optional embodiments of the method of this application.

[0027] like Figure 1 As shown, in step S101, the range of Reynolds numbers to be simulated is determined according to the performance requirements of the sensor to be calibrated and the target environmental conditions.

[0028] According to the target temperature, the target pressure and the target wind speed of the target environment condition, the jet Reynolds number of each calibration condition is calculated to determine the lowest Reynolds number to be simulated:

[0029]

[0030] wherein Re represents the lowest Reynolds number to be simulated; D is the diameter of the jet of the simulated air duct; μ is the dynamic viscosity of the gas, which can be obtained by looking up the table according to the target temperature; V ave represents the expected average speed of the gas out of the jet of the simulated air duct under the current calibration condition; T 目 and P 目 respectively represent the target temperature (in Kelvin) and the target pressure; R is the gas constant corresponding to different gases. For example, 297 for nitrogen and 189 for carbon dioxide. According to the above expression, the Reynolds number of the jet of the air duct under each calibration condition can be calculated, and thus the Reynolds number range to be simulated can be obtained. Meanwhile, the Reynolds number of the air duct with different air ducts is calculated considering the requirements of different calibration conditions.

[0031] Specifically, the performance requirements of the sensor to be calibrated include the speed range to be measured, the working temperature and the working pressure, etc.

[0032] According to the determined Reynolds number range to be simulated, the outlet Reynolds number of each calibration condition is higher than a specified value, which is 4000. The calibration conditions include temperature, pressure, gas composition, wind speed, wherein the gas composition includes carbon dioxide, nitrogen, etc.

[0033] In the application example of Figure 2 , the structure near the jet includes the sensor to be calibrated 201, the bracket 2011, the sensor sensitive head 2012, and the jet 410 of the air duct (i.e. the submerged jet).

[0034] It should be noted that in the present example, the sensor to be calibrated is built-in the space environment simulation container, and the calibration of the sensor to be calibrated is performed in the space environment simulation container. In addition, considering that when the Reynolds number is small, the wind speed of the jet often has a large non-uniform area, therefore, when selecting the corresponding air duct, the Reynolds number Re is limited to be greater than 4000, so as to increase the stable range of the jet as much as possible. The above is only described as an optional example, and should not be understood as a limitation of the present application.

[0035] It should be noted that in the present application, the space environment simulation container refers to the outermost container. The jet of the air duct here is the diameter of the jet of the simulation air duct built-in the space environment simulation container.

[0036] Next, in step S102, based on the determined Reynolds number range, a wind tunnel is selected which can form a stable submerged jet.

[0037] Specifically, according to the Reynolds number range calculated in step S101, a wind tunnel is selected which can form a stable submerged jet under the target environmental conditions.

[0038] Further, a wind tunnel nozzle is selected which can form a stable submerged jet under low pressure environment (i.e. corresponding to the converging section 409 in FIG. 4), and the selected wind tunnel nozzle includes a Wiberg curve, a double cubic curve, a quintic curve. Figure 2

[0039] It should be noted that in the present application, the wind field refers to the jet region formed after the wind tunnel nozzle is ejected, for example, a conical region with a bottom diameter of the diameter of the wind tunnel nozzle and a height of 5 to 10 times the diameter of the nozzle.

[0040] For example, if a wind speed of 20 m / s needs to be simulated under a nitrogen environment of 1400 Pa and -100°C, then according to the calculation, when the diameter of the wind tunnel nozzle is 0.04 m, the Reynolds number is about 1912. When the diameter of the wind tunnel nozzle is 0.14 m, the Reynolds number is about 6693, and at this time, the 0.14 m nozzle with a Reynolds number greater than 4000 is preferred. When a wind speed of 100 m / s needs to be simulated under a nitrogen environment of 5000 Pa and -100°C, then according to the calculation, when the diameter of the wind tunnel nozzle is 0.04 m, the Reynolds number is about 6829. When the diameter of the wind tunnel nozzle is 0.14 m, the Reynolds number is about 23903, and at this time, both the wind tunnels can be selected, and the 0.04 m nozzle with a smaller diameter is preferred because it has a lower gas consumption.

[0041] Figure 3 A schematic diagram of the nozzle velocity distribution obtained by applying the low pressure wind speed calibration optimization method of the embodiments of the present application.

[0042] As shown in FIG. 7, 701 is the wind speed distribution of Re = 50000, 702 is the wind speed distribution of Re = 15000, 703 is the fraction distribution of Re = 4000, 704 is the wind speed distribution of Re = 1000, 705 is the wind speed distribution of Re = 300, 706 is the wind speed stable region of Re = 300, and 707 is the geometric range of the entire wind tunnel nozzle. Figure 3 As can be seen from FIG. 7, when the Reynolds number is small, there is often a large non-uniform region of the wind speed of the wind tunnel nozzle, and therefore when the corresponding wind tunnel nozzle is selected, the Reynolds number Re is limited to be greater than 4000 to as much as possible to increase the stable range of the nozzle. Figure 3 It should be noted that the above is only an optional example for illustration and cannot be understood as a limitation of the present application.

[0043] It should be noted that the above is only an optional example for illustration and cannot be understood as a limitation of the present application.​

[0044] To further optimize the calibration process, the relevant parameters are adjusted. Specifically, in the calibration test of the sensor to be calibrated, the parameters (including pressure, temperature, flow, etc.) are continuously adjusted until all parameters are stable, and then the calibration process is performed using all adjusted (i.e. stable) parameters.

[0045] The parameter adjustment process will be described in detail below in connection with steps S103-S105.

[0046] Next, in step S103, the peak gas flow required for calibration is calculated according to the determined Reynolds number range and the selected air duct.

[0047] In the present example, the selected air duct nozzle is integrally formed with the simulated air duct. However, this is not limited thereto. Alternatively, the tapered section 409 (see "tapered section 409" in particular in Figure 2 may be replaced or assembled.

[0048] Specifically, according to the determined simulated air duct, the air duct diameter, i.e. the air duct nozzle diameter, of the simulated air duct can be determined, and the peak gas flow required for calibration can be further calculated.

[0049] It should be noted that the above is only described as an optional example and should not be construed as a limitation on the present application.

[0050] Next, in step S104, an appropriate pressure maintenance system is selected based on the peak gas flow.

[0051] For each calibration condition, different pressure control systems can be selected according to the selection principle.

[0052] Based on the calculated peak gas flow (e.g. the maximum volumetric flow of the air duct nozzle), it is determined whether the pressure in the space simulation environment container is greater than a specified value (e.g. 101% of the current pressure value, i.e. the control accuracy is selected to be 1% of the current pressure value, i.e. when the environmental pressure is 500 Pa, the control is performed with an accuracy of ± 5 Pa), and an appropriate level of pressure control system is selected for pressure control.

[0053] Specifically, based on the calculated peak gas flow (i.e. the maximum volumetric flow of the air duct nozzle), a more appropriate pressure control system (preferably a control component with a gas extraction amount close to the peak gas flow) on the space environment simulation container is selected, and after the air duct is started, the matching pressure control system (specifically the control component) is started in real time, and the gas extraction amount is adjusted in real time by the control component to achieve a match with the incoming gas flow, thereby achieving a dynamic balance between the gas extraction process and the gas entry process.

[0054] For example, the PID mode is used to control the valve opening of the corresponding control valve (e.g., the first control valve, the second control valve, etc.) in the matching control assembly in real time. For example, when the pressure in the space environment simulation container gradually increases to more than 101% of the current pressure value, the valve opening of the corresponding control valve is adjusted to gradually increase the pumping capacity of the pressure control system, thereby achieving dynamic pressure control.

[0055] Optionally, the selection principle includes: the expected pumping speed should be less than the maximum pumping speed of the expected pressure control system; the expected pumping speed should be greater than the first specified proportion (e.g., 10%) of the expected pumping speed of the pressure control system; the expected pumping speed should be greater than the second specified proportion (e.g., 50%) of the maximum pumping speed of the expected pressure control system.

[0056] For example, the pressure control system is a combination of vacuum pumps with different pumping speeds. Specifically, it includes a multi-stage control assembly. The multi-stage control assembly is arranged at different positions outside the space simulation environment air duct. Each stage of the control assembly includes a pumping pump, a pumping pipeline, and a control valve.

[0057] According to the above selection principle, the pumping speed is adjusted by adjusting the pumping pipeline valve to select the corresponding stage of the control assembly to control the pressure.

[0058] For the case where the expected pumping speed is greater than or equal to the maximum pumping speed of the expected pressure control system, the expected pumping speed is less than or equal to the first specified proportion (e.g., 10%) of the expected pumping speed of the pressure control system, and the expected pumping speed is less than or equal to the second specified proportion (e.g., 50%) of the maximum pumping speed of the expected pressure control system, the pumping speed is adjusted by adjusting the intake pipeline valve to select the corresponding pressure control system to control the pressure.

[0059] From Figure 4 It can be seen that 801, 802, and 803 represent the pumping speed range of the first stage control assembly, the second stage control assembly, and the third stage control assembly in the pressure control system, respectively, which needs to be selected according to the pressure and other parameters in the space environment simulation container under the current calibration condition. The three control assemblies, i.e., the first stage control assembly, the second stage control assembly, and the third stage control assembly, have different orders of magnitude of pumping speed, such as 1000 L / s, 100 L / s, and 10 L / s. 811, 812, and 813 represent the speed and flow curves under different working modes, respectively.

[0060] Specifically, 801 represents the applicable area of ​​the first-level control component, 802 the applicable area of ​​the second-level control component, and 803 the applicable area of ​​the third-level control component. 811, 812, and 813 are the calibration velocity and volumetric flow rate curves when using different nozzle models, respectively. In simulation experiments, selecting a pressure control system requires ensuring that the first, second, and third-level control components cover different wind speed ranges of the calibration curves, and combining this with the selection of control components of appropriate levels to achieve the most stable pressure control process.

[0061] It should be noted that the above is only an optional example and should not be construed as a limitation of this application.

[0062] Next, in step S105, the operating condition parameter data of the current space simulation environment is obtained, and the environmental parameters are adjusted until the environmental parameters are stable. The adjustment of environmental parameters includes calculating the nozzle volume flow rate and controlling multiple environmental parameters.

[0063] Specifically, the following calibration parameters of the current space simulation environment are obtained, including temperature, pressure, and gas.

[0064] At the air duct diameter (corresponding) Figure 2 Once the reduced diameter of the converging section 409 (i.e., the outlet diameter of the converging section 409) is determined, and the maximum gas flow rate (i.e., the maximum gas volumetric flow rate, sometimes also called the maximum volumetric flow rate of the duct nozzle) is known, the calibrated flow rate curve can be calculated separately for each calibration condition. The maximum gas volumetric flow rate of the duct nozzle can be expressed by the following expression:

[0065]

[0066] Among them, Q e V represents the maximum gas volumetric flow rate at the duct nozzle; ave This represents the expected average wind speed of the gas exiting the nozzle of the simulated air duct under the current calibration conditions; D is the nozzle diameter of the simulated air duct, i.e., the outlet diameter of the converging section.

[0067] It should be noted that since the air velocity of the gas coming out of the nozzle of the simulated air duct is not uniform, the ultimate goal is to achieve a uniform air velocity, i.e., the target air velocity. In other words, the target velocity is expected to be equal to the average velocity.

[0068] Therefore, using the above expression, the corresponding maximum volumetric flow rate can be calculated for each calibration condition.

[0069] Next, based on the calculated maximum gas volumetric flow rate of the air duct nozzle and the operating temperature under the current calibration conditions, the required gas volumetric flow rate before entering the heat exchanger can be calculated.

[0070] The target flow rate of the flow controller is calculated using the following expression:

[0071]

[0072] In the formula, Q 目 T represents the target flow rate controlled by the flow controller. 测 and P 测 These represent the Kelvin temperature and pressure of the gas before it enters the flow meter, respectively; P e Indicates the pressure under the current calibration condition; T e V represents the Kelvin temperature under the current calibration conditions. ave This represents the expected average wind speed of the gas exiting the nozzle of the simulated air duct under the current calibration conditions; D represents the diameter of the air duct nozzle.

[0073] In one alternative implementation, the parameter adjustment process specifically includes the following steps.

[0074] Step S201: Obtain parameter data of the calibration conditions of the current space simulation environment.

[0075] Specifically, the parameter data of the calibration conditions include temperature, pressure, and gas.

[0076] Step S202: Calculate the volumetric flow rate of the air duct nozzle based on the current calibration conditions.

[0077] Step S203: Select a pressure control system and perform pressure control.

[0078] Specifically, the pressure control system includes multi-level control components. These multi-level control components are located at different positions within the space simulation environment container. Each level of control component includes a vacuum pump, a vacuum pipeline, and a control valve.

[0079] For example, based on the calculated peak gas flow rate (i.e. the maximum volumetric flow rate of the air duct nozzle), a suitable pressure control system (preferably a control component whose pumping volume is close to the peak gas flow rate) is selected on the space environment simulation container. After the air duct is started, the corresponding pressure control system (specifically the control component) is started in real time. The control component adjusts the pumping volume in real time to match the incoming gas flow rate, thereby achieving a dynamic balance between the pumping process and the gas entering process.

[0080] Based on the airflow rate at the duct nozzle under the current calibration conditions, any one of the first-level control component, the second-level control component, or the third-level control component is dynamically selected. By adjusting the corresponding control valve, gas is extracted from the space simulation environment container, thereby achieving dynamic pressure balance within the space simulation environment container.

[0081] According to the volume flow rate of the air duct nozzle, the gas volume flow rate before entering the heat exchanger (i.e. the maximum volume flow rate corresponding to the air duct nozzle) is accurately controlled, for example by a mass flow meter (or a volume flow meter, or a flow controller), to form a quantitative flow with known temperature, pressure and flow rate, and only according to sensor measurement, when the pressure and temperature are known, the required flow rate can be calculated, rather than actively controlling the temperature and pressure.

[0082] Specifically, a flow controller is selected according to the calculated inlet volume flow rate, and an appropriate volume flow meter is selected, and the target value of the flow is set to accurately control the amount of gas entering the heat exchanger, i.e. the target value of the flow controller with a relatively matched range is set to the target inlet flow rate, and the target value of other gas flow controllers is set to zero.

[0083] Next, the flow control is started, i.e. according to the preset mode, the flow controller is started to control the flow to the target value. The temperature control is started, i.e. the two-stage temperature control system is started, the first stage is the liquid nitrogen heat exchanger, and the gas temperature is roughly controlled by adjusting the flow, and the second stage is the electric heater, and the temperature is accurately controlled by adjusting the power.

[0084] It should be noted that the above is only described as an optional example and cannot be understood as a limitation of the present application.

[0085] The calibration of the to-be-calibrated sensor and the evaluation of the calibrated data will be described in detail in step S106.

[0086] Next, in step S106, the to-be-calibrated sensor is calibrated and the calibrated data is evaluated based on the adjusted environmental parameters.

[0087] Specifically, the calibration of the to-be-calibrated sensor includes the following steps.

[0088] Step S301: Position zeroing of the to-be-calibrated wind speed sensor.

[0089] Specifically, the step motor is adjusted to rotate until the limit switch is triggered, so that the to-be-calibrated sensor is located at the zero point.

[0090] Step S302: Drive the to-be-calibrated wind speed sensor to move and record the output data of the to-be-calibrated wind speed sensor and the corresponding theoretical wind speed value at each scanning point.

[0091] The to-be-calibrated sensor is controlled to move in one direction and pass through the air duct nozzle, and all output data of the to-be-calibrated sensor during the entire movement process are automatically recorded.

[0092] Step S303: Selecting the extreme value measured by the to-be-calibrated wind speed sensor under each working condition as the calibration value under each working condition.

[0093] Selecting the extreme value under each working condition as the calibration value, since the speed of the nozzle (i.e. submerged jet nozzle) is not uniform, the speed near the center is closest to the theoretical value, and the speed at the edge is lower, therefore the extreme value of the sensor in the test is selected as the calibration value.

[0094] For example, for the calibration of a constant heat flow hot sphere wind speed sensor (i.e. to-be-calibrated sensor), the minimum point (maximum point of wind speed) of the millivolt signal is selected as the reference value.

[0095] Step S304: Establishing a preliminary calibration matrix.

[0096] Specifically, the preliminary calibration matrix includes two column vectors, the first column is the millivolt signal output by the to-be-calibrated sensor, and the second column is the processed wind speed reference value. Since the speed of the nozzle has a distribution characteristic, the speed in the central stable zone is slightly higher than the average speed, therefore the actual wind speed needs to be corrected, and the following expression is used to represent the corrected wind speed:

[0097] V 修正 = V ave × a

[0098] Wherein, V 修正 represents the wind speed corrected based on the wind tunnel structure and the outlet Reynolds number; V ave represents the expected average wind speed of the gas coming out of the nozzle of the simulated wind tunnel under the current calibration working condition; a is a function calculation characteristic value representing the correlation with the wind tunnel structure and the outlet Reynolds number, i.e. a calibration parameter, for each specific wind tunnel, a is obtained through simulation or test at the design time, and the Reynolds number is about 1.00-1.40.

[0099] Optionally, when the calibration parameter a is obtained through CFD simulation, the following expression is used to represent:

[0100]

[0101] Wherein, a represents the function calculation characteristic value representing the correlation with the wind tunnel structure and the outlet Reynolds number, i.e. a calibration parameter, obtained through CFD simulation; V r＝0 is the theoretical wind speed of the geometric center of the nozzle (the set center is the point with r=0), unit: m / s, and the geometric center of the nozzle is taken as the point with r=0, then is the integral average value of the nozzle wind speed, unit: m / s, where R is the maximum radius of the nozzle, and here r=R.

[0102] Figure 5is a schematic diagram showing the relationship between the radius of the wind tunnel nozzle and the wind speed in the low pressure wind speed calibration optimization method of the embodiments of the present application. Among them, the abscissa represents the position of the wind tunnel nozzle from the center to the boundary of the simulated wind tunnel, that is, the change of the radius of the wind tunnel nozzle, and the ordinate represents the wind speed of the wind tunnel nozzle from the center to the boundary of the simulated wind tunnel, that is, the dimensionless V / V 修正 .

[0103] From Figure 5 , when r = R, that is, at the boundary of the wind tunnel, due to the boundary layer effect, the current wind speed V at this position is zero, see Figure 5 .

[0104] It should be noted that in the present application, V, V 修正 are macroscopic flow, and V is the value of the wind tunnel nozzle from the center to the boundary of the simulated wind tunnel, that is, the local value, and the maximum value of V is V 修正 .

[0105] According to the law of conservation of mass, the flow rate into the space environment simulation container through the flow meter and the heat exchanger is the same as the mass flow rate of the wind tunnel nozzle, and the temperature and pressure of the gas entering the flow meter can be determined, that is, the measured T 测 , P 测 , the gas temperature of the wind tunnel nozzle is controlled to be the ambient temperature T e , and the pressure is the same as the ambient pressure in the container P e , therefore, when the flow rate of the flow meter is known, the expected average wind speed V ave of the wind tunnel nozzle can be determined, and combined with the calibration parameter a, the wind speed of the current wind tunnel nozzle stable zone, that is, the wind speed stable zone (see "706" in Figure 3 ) can be accurately obtained.

[0106] Therefore, the process based on pressure control realizes variable pumping capacity control, can work continuously, and can improve work efficiency. The mass flow meter directly forms a wind speed reference, effectively avoiding the problem of error accumulation. The use of multi-range flow meter and multiple pressure control systems can accurately obtain the wind speed of the current wind tunnel nozzle stable zone.

[0107] It should be noted that the wind field of the wind tunnel nozzle of the simulated wind tunnel is not completely uniform, but has a distribution characteristic, specifically, the wind speed at the center is slightly higher than the target wind speed, and the edge wind speed is lower than the target wind speed, therefore, it is necessary to obtain it by multiple iterations.

[0108] According to the established preliminary calibration matrix, for each calibration condition, the wind speed distribution of the nozzle during the movement of the sensor to be calibrated is calculated by linear interpolation, for example, according to the collected wind speed distribution, the integral average method can be used to calculate.

[0109] For the nozzle wind speed distribution, to determine whether the calibration data is correct, due to the characteristics of the jet, the wind speed in the middle stable zone should be completely consistent. By sampling multiple times in the middle region, the mean and standard deviation of the measured values can be calculated to reduce the uncertainty of the measurement.

[0110] In an optional embodiment, before starting the calibration of the sensor to be calibrated, it is determined whether all parameters are in a stable state.

[0111] After determining that all parameters are in a stable state, the calibration of the sensor to be calibrated is started.

[0112] Specifically, it is determined whether the entire calibration is completed, i.e., whether the calibration of all working conditions is completed. If not, the next calibration working condition is calibrated by re-entering step S301 of the calibration process.

[0113] It should be noted that in the present embodiment, the other steps are substantially the same as the above calibration process, and therefore the same content is omitted.

[0114] Further, the calibrated data is also evaluated.

[0115] Specifically, the obtained wind speed values of the nozzle wind speed distribution are compared with the reference values (i.e., theoretical values), and the error values between the wind speed values and the reference values (i.e., theoretical values) are calculated using the following expression:

[0116]

[0117] wherein RMSD represents the error values between the wind speed values and the reference values (i.e., theoretical values) using the root mean square error; t represents the starting position of the calibration of the sensor to be calibrated, t is a positive integer, n represents the total number of points in the calibration process of the sensor to be calibrated; V calc represents the wind speed values on the nozzle wind speed distribution curve corresponding to the obtained nozzle wind speed distribution; V theory represents the reference values on the theoretical curve, i.e., the theoretical values.

[0118] Through the above root mean square error calculation, the error values between the current curve and the theoretical curve can be evaluated.

[0119] According to the error calculation of the calculated nozzle wind speed distribution of the sensor to be calibrated during movement and the reference values, when the calculated error value is less than a threshold value, it indicates that the calibration data is valid; when the calculated error value is less than the threshold value, it indicates that the calibration data is invalid, and the calibration process is re-executed.

[0120] Compared with the prior art, the application forms a continuous wind field based on the internal and external pressure difference of the current space simulation environment, determines the Reynolds number range to be simulated according to the performance requirements and target environment conditions of the sensor to be calibrated, selects a wind tunnel capable of forming a stable submerged jet, calculates the peak gas flow required for calibration according to the determined Reynolds number range and the selected wind tunnel, can accurately select an appropriate pressure maintenance system, and can improve the pressure control accuracy; by obtaining the working condition parameter data of the current space simulation environment, adjusting the environment parameters until the environment parameters are stable, and calibrating the sensor to be calibrated based on the adjusted environment parameters, more accurate calibration data can be obtained; by evaluating the calibration data after calibration, the calibration error caused by the calibration jet velocity distribution is evaluated and corrected, and more accurate calibration results can be obtained.

[0121] In addition, the process based on pressure control realizes variable extraction control and can work continuously; the wind speed reference is directly formed based on the mass flow meter, and there is no error accumulation problem; a multi-range flow meter and a multi-pressure control system matching mode are adopted.

[0122] The following will be described in detail with reference to the accompanying drawings Figure 2 and Figure 6 The optional embodiments of the system of the application will be described in detail.

[0123] Referring to Figure 2 and Figure 6 , the low-pressure wind speed calibration optimization system includes a space environment simulation container 101, a simulation wind tunnel built in the space environment simulation container 101, a sensor to be calibrated 201, a wind tunnel inlet pipe 401 connected with the simulation wind tunnel, a gas source 501, a heat exchanger 506 located between the gas source 501 and the wind tunnel inlet pipe 401, and a pressure control system connected with the space environment simulation container 101. The low-pressure wind speed calibration optimization system is used to execute the low-pressure wind speed calibration optimization method of the application.

[0124] As shown in Figure 6 , the space environment simulation container 101 is used to simulate a low-temperature (for example, the temperature range is-150℃-20℃) and low-pressure (for example, the pressure range is 100pa-101325Pa) environment, and is a horizontal cylindrical large vacuum container. The heat sink 102 is installed in the interior of the space environment simulation container 101 and is uniformly distributed along the circumference of the space environment simulation container, and the heat sink temperature can be set to-196℃-0℃, providing the ability to simulate a low-temperature environment.

[0125] From Figure 2The to-be-calibrated sensor 201, i.e., the to-be-calibrated wind speed sensor, can be a thermal wind speed probe in an embodiment. The signal of the to-be-calibrated sensor 201 can be transmitted outside the space environment simulation container 101 through the combination of the wind speed sensor measurement cable 202, the test electrical connector 203, and the test cable (out) 204. The wind speed acquisition system 205 is used to acquire the original signal of the to-be-calibrated sensor 201, and the wind speed acquisition system 205 is, for example, a voltage measurement device.

[0126] It should be noted that the system of the present application is particularly suitable for application scenarios such as Mars probes and stratospheric low-speed aircrafts. In the ground verification of Mars probes and stratospheric aircrafts, it is usually necessary to simulate the extreme convective environment faced by the probes and aircrafts. The present application can more accurately and effectively calibrate the wind speed sensor, i.e., the to-be-calibrated sensor, before the ground simulation test, so that the calibrated wind speed sensor can effectively measure the wind speed in a low-pressure environment (the Mars environment is 700 Pa, and the typical 20 km stratosphere environment is 5500 Pa) in the ground simulation test.

[0127] Specifically, the pressure control system includes a multi-stage control assembly. The multi-stage control assembly is arranged at different positions of the space simulation environment container. Each stage of the control assembly includes a gas extraction pump, a gas extraction pipeline, and a control valve.

[0128] Based on the calculated wind tunnel nozzle volume flow, it is determined whether the pressure in the space simulation environment container 101 is greater than a specified value (for example, 101% of the current pressure value, i.e., the control accuracy is selected to be 1% of the current pressure value, i.e., 500 Pa of the environmental pressure is controlled according to the accuracy of ±5 Pa), and the pressure control system of the selected adaptive level is selected for pressure control.

[0129] For example, based on the calculated peak gas flow (i.e., the maximum volume flow of the wind tunnel nozzle), a more suitable pressure control system (preferably a control assembly with a gas extraction amount close to the peak gas flow) on the space environment simulation container is selected. After the wind tunnel is started, the matching pressure control system (specifically, the control assembly) is started in real time, and the gas extraction amount is adjusted in real time by the control assembly to match the entering gas flow, thereby realizing a dynamic balance between the gas extraction process and the gas entering process.

[0130] For another example, a PID method is used for control, and the valve opening of the control valve (for example, the first control valve, the second control valve, etc.) in the matching control assembly is adjusted in real time. For example, when the pressure in the space environment simulation container gradually rises to more than 101% of the current pressure value, the valve opening of the corresponding control valve is adjusted to gradually increase the gas extraction amount of the pressure control system, thereby realizing dynamic pressure control.

[0131] According to the outlet flow of the nozzle under the current calibration condition, any one of the first control assembly, the second control assembly and the third control assembly is selected, and the corresponding control valve is adjusted to extract the gas in the space simulation environment container 101, so as to realize the dynamic balance of the pressure in the space simulation environment container 101.

[0132] The first control assembly comprises a first air extraction pump 301, a first air extraction pipe 302, a first control valve 303, a second control valve 304 and a first air inlet pipe 305. The first air extraction pump 301 is a volumetric air pump for extracting gas. The first air extraction pipe 302 is connected with the space environment simulator 101 and the air extraction pump 1, and is used for extracting gas. The first control valve 303 is an opening valve. By adjusting the opening of the first control valve, the flow resistance of the first air extraction pipe 302 can be changed, so that the air extraction amount of the first air extraction pump 301 is changed, and the purpose of pressure control is achieved. The second control valve 304 is an opening valve 12. By adjusting the opening of the second control valve 304, more air can be extracted from the external environment (i.e. the atmospheric environment in which the space environment simulator 101 is located) by the first air extraction pump 301, and less gas can be extracted from the space environment simulator 101, so as to achieve the purpose of pressure control; or less air can be extracted from the external environment (i.e. the atmospheric environment in which the space environment simulator 101 is located), and more gas can be extracted from the space environment simulator 101, so as to achieve the purpose of pressure control; the first air inlet pipe 305 is connected with the second control valve 304, and is used for introducing external gas.

[0133] Further, the second control assembly comprises a second air extraction pump 311, a second air extraction pipe 312, a third control valve 314, a fourth control valve 315 and a second air inlet pipe 321. The third control assembly comprises a third air extraction pump 321, a third air extraction pipe 323, a fifth control valve 324, a sixth control valve 325 and a second air inlet pipe 325.

[0134] It should be noted that, since the components of the first control assembly are similar to the components of the second control assembly and the third control assembly in principle, they are composed of pumps with different extraction speeds to meet different extraction speed requirements. Therefore, the same content is omitted.

[0135] It can be known from Figure 6 that the air duct air inlet pipe 401 is an interface outside the air duct, i.e. the air duct, for introducing the gas supplied by the gas source 501 into the air duct. The air duct air inlet pipe 401 is connected and fixed to the space environment simulation container 101 by the wall flange 402, and part of the air duct air inlet pipe 401 is located in the air duct to introduce gas into the air duct, thereby ensuring the air tightness of the space environment simulation container 101 while introducing external gas.

[0136] Further, the wind tunnel stable section 403 is used to gradually stabilize the introduced gas flow, simulating the installation of a honeycomb flow straightener 406, a first turbulence reduction net 407, and a second turbulence reduction net 408 inside the wind tunnel, and after the gas passes through the wind tunnel stable section, the gas flow becomes substantially horizontal. The gas flow diffusion port 404 is the outlet of the wind tunnel stable section 403 through which the gas flow from the wind tunnel inlet pipeline 401 enters the wind tunnel stable section 403. The baffle plate 405 is used to disperse the gas flow from the gas flow diffusion port 404 to prevent uneven velocity caused by direct impact. The honeycomb flow straightener 406 is used for the first step of straightening the air flow to make the air flow approximately horizontal. Further, the simulation wind tunnel further includes a first turbulence reduction net 407 and a second turbulence reduction net 408, which are used to further disperse small eddies on the basis of the honeycomb flow straightener 406 to improve the quality of the gas flow. The tapered section 409 is a gradually tapered section, i.e., a calibrated wind tunnel of the simulation wind tunnel. For example, through the Vickers curve, the wind tunnel nozzle is contracted in a short distance to further improve the quality of the gas flow. The wind tunnel nozzle 410 is a submerged jet nozzle, which is used to form a stable flow, and the sensor to be calibrated can be installed and the parameters can be calibrated, such as the wind speed calibration of the wind tunnel nozzle.

[0137] Optionally, the gas source 501 is used to supply gas to the calibrated wind tunnel of the simulation wind tunnel, for example, a high-pressure gas cylinder. The gas supplied by the gas source 501 is reduced in pressure by the pressure reducing valve 502, for example, to about 1 Bar. After the pressure reduction, the pressure of the current gas (the gas before entering the heat exchanger) is measured by the pressure sensor 503, and the required volume flow is calculated therefrom. The temperature of the current gas is measured by the temperature sensor 504. For example, multiple temperature sensors are included to measure the temperature at multiple different positions.

[0138] Further, it further includes a flow controller group 505, a heat exchanger 506, and an electric heater 507. The flow controller group 505 includes a group of controllers with different flow ranges to cover different wind speed ranges for calibration. The heat exchanger 506 is a liquid nitrogen heat exchanger, which is used to transfer the cold energy of the liquid nitrogen to the working medium, i.e., the gas forming the wind (for transferring to the gas entering the simulation wind tunnel), to reduce the temperature of the gas entering the calibrated wind tunnel of the simulation wind tunnel. The electric heater 507 is used to further accurately control the temperature of the gas on the basis of the heat exchanger 506, so that the temperature of the gas entering the wind field is equivalent to the calibration temperature.

[0139] From Figure 2 It can be known from the structure near the wind tunnel nozzle that the structure includes a bracket 2011 of the sensor to be calibrated 201, a sensor sensitive head 2012, a moving block 601, a fixed bolt 602, a lead screw 603, an optical axis 604, lead screw fixed ends 6051 and 6052 of the optical axis, a coupling 606, a stepping motor 607, and a limit switch 608.

[0140] Specifically, the support 2011 is a support rod part of the sensor to be calibrated. The inside of the sensor sensitive head 2012 is a structure of a hot wire, a hot line, a hot film, a hot ball, etc. The moving block 601 is used to carry the sensor to be calibrated 201 and can move left and right. The fixed bolt 602 is used to fix the sensor to be calibrated 201 on the moving block 601. The lead screw 603 is used to convert the rotary motion of the stepper motor 607 into the left and right movement of the moving block 601. The optical axis 604 is used to limit the degree of freedom of the moving block 601, and cooperates with the lead screw 603 to guide the moving block 601. The lead screw fixed ends 6051 and 6052 are respectively used to fix the two ends of the optical axis 604 and the lead screw 603. The shaft coupling 606 is used to connect the stepper motor 607 and the lead screw. The stepper motor 607 is used to rotate at a constant speed according to the system design to realize stable movement of the moving block 601. The limit switch 608 is used to protect the system and limit the zero position of the moving block 601.

[0141] The low-pressure wind speed calibration optimization system is used to calibrate the sensor to be calibrated, including: position zeroing of the wind speed sensor to be calibrated; driving the wind speed sensor to be calibrated to move and recording the output data of the wind speed sensor to be calibrated and the corresponding theoretical wind speed value at each scanning point. Selecting the extreme value measured by the wind speed sensor to be calibrated under each working condition as the calibration value under each working condition; and establishing a preliminary calibration matrix.

[0142] According to an optional embodiment, according to the established preliminary calibration matrix, for each calibration working condition, the nozzle wind speed distribution of the moving process of the sensor to be calibrated is calculated by linear interpolation respectively.

[0143] According to an optional embodiment, according to the calculated nozzle wind speed distribution of the moving process of the sensor to be calibrated and the reference value, the error is calculated, wherein the following expression is used to represent the corrected wind speed:

[0144] V 修正 = V ave × a

[0145] Wherein, V 修正 represents the corrected wind speed based on the wind tunnel structure and the outlet Reynolds number; V ave represents the expected average wind speed of the gas coming out of the nozzle of the simulated wind tunnel under the current calibration working condition; a is a function representing the characteristic value, i.e. the calibration parameter, related to the wind tunnel structure and the outlet Reynolds number, and for each specific wind tunnel, a is obtained by simulation or test at the design time.

[0146] The modified wind speed is compared with the corresponding reference value to calculate the error, wherein when the calculated error value is less than a threshold value, it indicates that the calibration data is valid; when the calculated error value is less than the threshold value, it indicates that the calibration data is invalid, and the calibration process is re-executed.

[0147] According to an optional embodiment, the following working condition parameter data of the current space simulation environment are acquired: temperature, pressure, gas. According to the current calibration working condition, the volume flow rate of the air duct nozzle is calculated; a pressure control system is selected to perform pressure control; according to the volume flow rate of the air duct nozzle, the volume flow rate of the air field inlet is calculated; flow control and temperature control are performed.

[0148] According to an optional embodiment, the following expression is used to calculate the control target flow rate of the flow controller:

[0149]

[0150] wherein Q 目 represents the control target flow rate of the flow controller; T 测 and P 测 respectively represent the measured Kelvin temperature and pressure of the gas before entering the flow meter; P e represents the pressure of the current calibration working condition; T e represents the Kelvin temperature of the current calibration working condition; V ave represents the expected average wind speed of the gas from the air duct nozzle of the simulation air duct under the current calibration working condition; and D represents the diameter of the air duct nozzle.

[0151] According to an optional embodiment, the nozzle Reynolds number under each calibration working condition is calculated according to the target temperature, the target pressure, and the target wind speed to determine the lowest Reynolds number to be simulated:

[0152]

[0153] wherein Re represents the lowest Reynolds number to be simulated; D is the diameter of the air duct nozzle of the simulation air duct; μ is the dynamic viscosity of the gas, which can be obtained by looking up a table according to the target temperature; V ave represents the expected average wind speed of the gas from the air duct nozzle of the simulation air duct under the current calibration working condition; T 目 and P 目 respectively represent the target temperature and the target pressure; and R is the gas constant corresponding to different gases.

[0154] According to the determined Reynolds number range to be simulated, the outlet Reynolds number of each calibration working condition is higher than a specified value, and the specified value is 4000.

[0155] The air duct that can form a stable submerged jet in a low-pressure environment is selected, and the selected air duct includes a Wessel curve, a double-cubic curve, and a quintic curve.

[0156] It should be noted that the low-pressure wind speed calibration and optimization method performed by the low-pressure wind speed calibration and optimization system in the embodiment is substantially the same as the low-pressure wind speed calibration and optimization method of the present application, and therefore the same content is omitted.

[0157] Compared with the prior art, the application forms a continuous wind field based on the internal and external pressure difference of the current space simulation environment, determines a Reynolds number range to be simulated according to the performance requirement of the sensor to be calibrated and target environment conditions, selects a wind tunnel capable of forming a stable submerged jet flow, calculates a peak gas flow required for calibration according to the determined Reynolds number range and the selected wind tunnel, can accurately select a suitable pressure maintaining system, and can improve the pressure control precision; obtains working condition parameter data of the current space simulation environment, adjusts the environment parameters until the environment parameters are stable, calibrates the sensor to be calibrated based on the adjusted environment parameters, and can obtain more accurate calibration data; evaluates the calibration data after calibration, evaluates and corrects the calibration error caused by the calibration jet flow velocity distribution, and can obtain more accurate calibration results.

[0158] In addition, the process based on pressure control realizes variable air extraction control and can work continuously; the wind speed reference is directly formed based on the mass flow meter, and there is no error accumulation problem; a multi-range flow meter and a plurality of pressure control systems are matched.

[0159] As shown in Figure 7 The electronic device includes at least one processor and a memory communicatively connected to the at least one processor, wherein the memory stores instructions executable by the one processor, and the instructions are executed by the at least one processor to enable the at least one processor to perform the method steps of the above embodiments.

[0160] The non-volatile computer storage medium stores computer executable instructions, and the computer executable instructions can execute the method steps of the above embodiments.

[0161] Reference is made below to Figure 7 , which shows a structural schematic diagram of an electronic device suitable for implementing the embodiments of the application. The terminal device in the embodiments of the application can include, but is not limited to, mobile terminals such as mobile phones, notebook computers, digital broadcast receivers, PDAs (personal digital assistants), PADs (tablets), PMPs (portable multimedia players), vehicle-mounted terminals (such as vehicle-mounted navigation terminals), and the like, and fixed terminals such as digital TVs, desktop computers, and the like. Figure 7 The electronic device shown is only an example and should not impose any limitation on the functions and use range of the embodiments of the application.

[0162] As shown in Figure 7As shown, the electronic device can include a processing device (e.g., a central processing unit, a graphics processing unit, etc.) 401 that can perform various appropriate actions and processes according to programs stored in a read-only memory (ROM) 402 or loaded into a random access memory (RAM) 403 from a storage device 408. Various programs and data required for operation of the electronic device are also stored in the RAM 403. The processing device 401, the ROM 402, and the RAM 403 are connected to each other through a bus 404. An input / output (I / O) interface 405 is also connected to the bus 404.

[0163] Generally, the following devices can be connected to the I / O interface 405: input devices 406 including, for example, a touch screen, a touch pad, a keyboard, a mouse, a camera, a microphone, an accelerometer, a gyroscope, etc.; output devices 407 including, for example, a liquid crystal display (LCD), a speaker, a vibrator, etc.; storage devices 408 including, for example, a magnetic tape, a hard disk, etc.; and communication devices 409. The communication devices 409 can allow the electronic device to communicate wirelessly or wired with other devices to exchange data. Although Figure 7 The electronic device is shown with various devices, but it is understood that all of the shown devices are not required to be implemented or present. More or less devices can alternatively be implemented or present.

[0164] In particular, according to embodiments of the present application, the processes described above with reference to the flowcharts can be implemented as a computer software program. For example, embodiments of the present application include a computer program product comprising a computer program carried on a computer readable medium, the computer program containing program code for performing the methods shown in the flowcharts. In such embodiments, the computer program can be downloaded and installed from a network through the communication devices 409, or installed from the storage devices 408, or installed from the ROM 402. When the computer program is executed by the processing device 401, the above-mentioned functions defined in the methods of embodiments of the present application are performed.

[0165] It should be noted that the computer-readable medium in the present application can be a computer-readable signal medium or a computer-readable storage medium or any combination thereof. The computer-readable storage medium may, for example, but is not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, device or apparatus, or any combination thereof. More specific examples of the computer-readable storage medium can include, but are not limited to, an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or flash memory), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the above. In the present application, the computer-readable storage medium can be any tangible medium that contains or stores a program that can be used by or in connection with an instruction execution system, apparatus or device. In the present application, the computer-readable signal medium can include a data signal carried in a baseband or as a part of a carrier wave, which carries computer-readable program code. Such a propagated data signal can take various forms, including, but not limited to, an electromagnetic signal, an optical signal, or any suitable combination of the above. The computer-readable signal medium can also be any computer-readable medium other than the computer-readable storage medium that can send, propagate or transmit the program for use by or in connection with an instruction execution system, apparatus or device. The program code contained on the computer-readable medium can be transmitted using any suitable medium, including, but not limited to, a wire, an optical fiber, an RF (radio frequency) or the like, or any suitable combination of the above.

[0166] The computer-readable medium described above can be contained in the electronic device described above; or can exist separately and not be assembled into the electronic device.

[0167] The computer program code for carrying out operations of the present application can be written in one or more programming languages or combinations of languages including object-oriented languages, such as Java, Smalltalk, C++, and conventional procedural programming languages, such as the "C" programming language or similar programming languages. The program code can execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer, or entirely on the remote computer or server. In the latter scenario, the remote computer can be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection can be made to an external computer (for example, through the Internet using an Internet Service Provider).

[0168] The flowcharts and block diagrams in the accompanying drawings illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of this application. In this regard, each block in a flowchart or block diagram may represent a module, segment, or portion of code containing one or more executable instructions for implementing a specified logical function. It should also be noted that in some alternative implementations, the functions indicated in the blocks may occur in a different order than those indicated in the drawings. For example, two consecutively indicated blocks may actually be executed substantially in parallel, and they may sometimes be executed in reverse order, depending on the functions involved. It should also be noted that each block in the block diagrams and / or flowcharts, and combinations of blocks in the block diagrams and / or flowcharts, can be implemented using a dedicated hardware-based system that performs the specified function or operation, or using a combination of dedicated hardware and computer instructions.

[0169] The units described in the embodiments of this application can be implemented in software or hardware. The names of the units are not, in some cases, limiting the scope of the unit itself.

Claims

1. A method for calibrating and optimizing low-pressure wind speed, characterized in that, include: The range of Reynolds numbers to be simulated is determined based on the performance requirements of the sensor to be calibrated and the target environmental conditions. Based on the determined Reynolds number range, select a wind duct that can form a stable sinking jet; Calculate the peak gas flow rate required for calibration based on the determined Reynolds number range and the selected duct. Based on the peak gas flow rate, select a suitable pressure maintenance system; The operating parameters of the current space simulation environment are acquired, and the environmental parameters are adjusted until they stabilize. The adjustment of environmental parameters includes calculating the nozzle volume flow rate and controlling multiple environmental parameters. Based on the adjusted environmental parameters, the sensor to be calibrated is calibrated, and the calibrated data is evaluated.

2. The low-pressure wind speed calibration and optimization method according to claim 1, characterized in that, The calibration of the sensor to be calibrated includes: Zero the position of the wind speed sensor to be tested; The wind speed sensor is driven to move, and the output data of the wind speed sensor and the corresponding theoretical wind speed value are recorded at the position of each scanning point. The extreme values ​​measured by the wind speed sensor under each working condition are selected as the calibration values ​​under each working condition. Establish a preliminary calibration matrix.

3. The low-pressure wind speed calibration and optimization method according to claim 1, characterized in that, Further includes: Based on the established preliminary calibration matrix, for each calibration condition, linear interpolation is used to calculate the nozzle wind speed distribution during the movement of the sensor to be calibrated.

4. The low-pressure wind speed calibration and optimization method according to claim 3, characterized in that, Further includes: Error calculations are performed based on the calculated nozzle wind speed distribution during the movement of the sensor to be calibrated and a reference value. The corrected wind speed is represented by the following expression: V 修正 =V ave ×a Among them, V 修正 V represents the wind speed after correction based on the duct structure and the outlet Reynolds number; ave represents the expected average wind speed of the gas exiting the nozzle of the simulated duct under the current calibration conditions; 'a' is a function value related to the duct structure and outlet Reynolds number, i.e., the calibration parameter. For each specific duct, 'a' is obtained through simulation or testing during the design phase. The error between the modified wind speed and the corresponding reference value is calculated, where... When the calculated error value is less than the threshold, it indicates that the calibration data is valid; If the calculated error value is less than the threshold, it indicates that the calibration data is invalid and the calibration process is re-executed.

5. The low-pressure wind speed calibration and optimization method according to claim 1, characterized in that, include: Obtain the following operating parameters of the current space simulation environment: temperature, pressure, and gas. Calculate the volumetric flow rate of the air duct nozzle based on the current calibration conditions; Select a pressure control system to control the pressure; Calculate the inlet volumetric flow rate of the wind field based on the volumetric flow rate of the air duct nozzle; Perform flow control and temperature control.

6. The low-pressure wind speed calibration and optimization method according to claim 5, characterized in that, include: The target flow rate of the flow controller is calculated using the following expression: Among them, Q 目 T represents the target flow rate controlled by the flow controller. 测 and P 测 These represent the Kelvin temperature and pressure of the gas before it enters the flow meter, respectively; P e Indicates the pressure under the current calibration condition; T e V represents the Kelvin temperature under the current calibration conditions. ave This represents the expected average wind speed of the gas exiting the nozzle of the simulated air duct under the current calibration conditions; D represents the diameter of the air duct nozzle.

7. The low-pressure wind speed calibration and optimization method according to claim 1, characterized in that, The process of determining the Reynolds number range to be simulated based on the performance requirements of the sensor to be calibrated and the target environmental conditions includes: Based on the target temperature, target pressure, and target wind speed, the nozzle Reynolds number under various calibration conditions is calculated to determine the minimum Reynolds number to be simulated. Where Re represents the minimum Reynolds number to be simulated; D is the nozzle diameter of the simulated air duct; μ is the dynamic viscosity of the gas, which can be obtained from a table based on the target temperature; V ave T represents the expected average wind speed of the gas exiting the nozzle of the simulated air duct under the current calibration conditions; 目 and P 目 These represent the target temperature and target pressure, respectively; R is the gas constant corresponding to different gases.

8. The low-pressure wind speed calibration and optimization method according to claim 1 or 7, characterized in that, Based on the determined range of Reynolds numbers to be simulated, the outlet Reynolds number for each calibration condition is made higher than a specified value, which is 4000.

9. The low-pressure wind speed calibration and optimization method according to claim 8, characterized in that, include: The selected air ducts can form a stable submerged jet in a low-pressure environment. The selected air ducts include Vickers curves, bicubic curves, and quintic curves.

10. A low-pressure wind speed calibration and optimization system, characterized in that, The method for low-pressure wind speed calibration and optimization according to any one of claims 1 to 9 includes: The space environment simulation container, the simulated air duct built into the space environment simulation container, the sensor to be calibrated, the air duct inlet pipe connected to the simulated air duct, the air source, the heat exchanger located between the air source and the air duct inlet pipe, and the pressure control system connected to the space environment simulation container.

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