Flow tube calibration data processing method

Abstract

The present disclosure relates to the technical field of flow tube calibration, and particularly relates to a flow tube calibration data processing method. The flow tube calibration data processing method comprises: determining a piecewise linear function of radial distribution of boundary total pressure P s and total pressure P t within a boundary layer based on measured static pressure P tbl_cri and total pressure P tbl at a measurement section of a flow tube; and determining a thickness δ of the boundary layer based on the determined piecewise linear function of radial distribution of boundary total pressure P tbl_cri and total pressure P tbl within the boundary layer. Thus, the deviation caused by the distance between adjacent measurement points can be reduced, the thickness of the boundary layer can be more accurate, and the accuracy of the flow tube calibration result can be effectively improved.

Description

Technical Field

[0001] This disclosure relates to the field of flow tube calibration technology, and in particular to a flow tube calibration data processing method. Background Technology

[0002] Flow measurement using flow tubes is required on test benches for components such as the core engine, the complete engine test bench, and the compressor of aero-engines. To improve the accuracy of flow measurement results during testing, the flow tubes need to be calibrated before the test.

[0003] Boundary layer thickness is a critical parameter in the flow tube calibration process. In related technologies, the following methods are commonly used to determine the boundary layer thickness:

[0004] The total pressure data of the boundary layer and the main flow zone within the measurement section are measured using a probe. The measured total pressure data of the boundary layer is compared with the total pressure data of the main flow zone. When the total pressure data of a certain measuring point in the boundary layer is close to or equal to the total pressure data of the measuring point in the main flow zone, this position is considered to be the boundary layer boundary. The radial distance from the corresponding position to the wall is then determined as the boundary layer thickness.

[0005] However, the above method directly determines the boundary layer thickness based on measurement point data, which is constrained by the spacing between adjacent measurement points, affecting the accuracy of the boundary layer thickness determination results, and consequently affecting the accuracy of the flow tube calibration results. Summary of the Invention

[0006] One of the technical problems that this disclosure aims to solve is to improve the accuracy of flow tube calibration results.

[0007] To address the aforementioned technical problems, this disclosure provides a method for processing flow tube calibration data, comprising:

[0008] Based on the measured static pressure P at the measuring section of the flow tube s and total pressure P t Data to determine the total boundary pressure P of the boundary layer. tbl_cri and the total pressure P within the boundary layer tbl A piecewise linear function with radial distribution;

[0009] Based on the determined total boundary pressure P of the boundary layer tbl_cri and the total pressure P within the boundary layer tbl The radially distributed piecewise linear function is used to determine the boundary layer thickness δ.

[0010] In some embodiments, based on the measured static pressure P at the flow tube measurement section. s and total pressure P t Data to determine the total boundary pressure P of the boundary layer. tbl_cri include:

[0011] Based on the measured static pressure Ps and the total pressure P in the mainstream area t0 Data to determine the Mach number Ma0 in the mainstream region;

[0012] Based on the Mach number Ma0 in the mainstream region, the gas velocity v0 in the mainstream region is determined.

[0013] Based on the mainstream gas velocity v0, determine the boundary gas velocity v at the boundary layer. tbl_cri ;

[0014] Based on the boundary gas velocity v of the boundary layer tbl_cri Determine the total boundary pressure P of the boundary layer. tbl_cri .

[0015] In some embodiments, the boundary layer boundary gas velocity v is determined based on the mainstream gas velocity v0. tbl_cri include:

[0016] The boundary gas velocity v0 is taken as 0.99 times the mainstream gas velocity v0. tbl_cri .

[0017] In some embodiments, based on the boundary gas velocity v at the boundary layer tbl_cri Determine the total boundary pressure P of the boundary layer. tbl_cri include:

[0018] The boundary gas velocity v at the boundary layer tbl_cri Substitute the gas flow velocity v with the Mach number Ma and the Mach number Ma with the total pressure P t The calculation formula between them yields the total boundary pressure P of the boundary layer. tbl_cri ;

[0019] The formula for calculating the relationship between gas flow velocity v and Mach number Ma is as follows: Mach number Ma and total pressure P t The calculation formula between them is: k is the specific heat ratio, R is the gas constant of air, and T is the specific heat ratio. s For static temperature, static temperature T s With total temperature T t The relationship between them is

[0020] In some embodiments, based on the measured static pressure P at the flow tube measurement section. s and total pressure P t Data to determine the total pressure P within the boundary layer. tbl The radially distributed piecewise linear functions include:

[0021] Based on the measured static pressure P s and the total pressure P at each measuring point t Based on the data and the assumption that the total pressure between two radially adjacent measuring points within the boundary layer is linearly distributed, the total pressure P within the boundary layer is established.tbl The piecewise linear function of the radial distribution is:

[0022]

[0023] Where Δ is the radial distance between two adjacent total pressure measuring points on the flow tube measuring section; x is the radial height from the wall; and i is the sequence number of each measuring point arranged sequentially from the wall to the center.

[0024] In some embodiments, based on the determined boundary layer boundary total pressure P tbl_cri and the total pressure P within the boundary layer tbl The radially distributed piecewise linear function is used to determine the boundary layer thickness δ, which includes:

[0025] Based on the total pressure P in the boundary layer tbl Given a piecewise linear function with radial distribution, determine the expression for the radial height x from the wall. And based on the total boundary pressure P of the boundary layer tbl_cri Determine the measured total boundary layer pressure P. tbl The total pressure P at the boundary of the boundary layer in the data tbl_cri Two adjacent total pressure values ​​P tbl(i) and P tbl(i-1) And two total pressure values ​​P tbl(i) and P tbl(i+1) The corresponding measurement point numbers i and i+1;

[0026] The determined P tbl(i) P tbl(i+1) i, i+1 and the total boundary pressure P of the boundary layer tbl_cri Substitute into the formula The calculated x value is taken as the boundary layer thickness δ.

[0027] In some embodiments, the flow tube calibration data processing method further includes:

[0028] Based on the determined boundary layer thickness δ, the mass flow rate m within the boundary layer is determined. BL .

[0029] In some embodiments, the mass flow rate m within the boundary layer is determined based on the determined boundary layer thickness δ. BL include:

[0030] Based on the determined boundary layer thickness δ, the mass flow rate m within the boundary layer is determined using an integral method. BL .

[0031] In some embodiments, the mass flow rate m within the boundary layer is determined using an integral method based on the determined boundary layer thickness δ. BL include:

[0032] Based on the total pressure P within the boundary layer tbl The radial distribution piecewise linear function is used to determine the density ρ within the boundary layer. bl and gas velocity v in the boundary layer bl The relationship between the boundary layer toroidal area dS and the radial height x from the wall is obtained by integrating the expression and the relationship between the boundary layer toroidal area dS and the radial height x from the wall.

[0033] The density ρ within the boundary layer bl Gas velocity v in the boundary layer bl Substituting the expression relating the toroidal area dS of the boundary layer to the radial height x from the wall into the integral formula m BL =∑∫ρvdG, with 0 and boundary layer thickness δ as the integral formulas respectively. BL The lower and upper limits of =∑∫ρvdS are used to obtain the mass flow rate m in the boundary layer. BL .

[0034] In some embodiments, the flow tube calibration data processing method further includes:

[0035] Based on the determined mass flow rate m within the boundary layer BL Determine the flow coefficient C d .

[0036] In some embodiments, based on the determined mass flow rate m within the boundary layer BL Determine the flow coefficient C d include:

[0037] Based on the measured static pressure P s Total temperature T t and total pressure P t Based on the data and the measured cross-sectional diameter D, the theoretical flow rate m is determined. ideal Based on the measured static pressure P s Total temperature T t and total pressure P t Based on the data, the cross-sectional diameter D, and the boundary layer thickness δ, the flow rate m in the main flow zone is determined. main ;

[0038] Based on the determined mass flow rate m within the boundary layer BL Theoretical flow rate m ideal and mainstream area traffic m main Determine the flow coefficient C d .

[0039] In some embodiments, the flow tube calibration data processing method further includes:

[0040] Based on the measured static pressure P under different working conditions s Total temperature T t and total pressure P tData was used to determine the Mach number Ma and flow coefficient C under different operating conditions. d Based on the determined Mach number Ma and flow coefficient C under different operating conditions d Establish flow coefficient C d The relationship between Mach number Ma and the expression; and / or,

[0041] Based on the measured static pressure P under different working conditions s Total temperature T t and total pressure P t Data was used to determine the Reynolds number (Re) and flow coefficient (C) under different operating conditions. d Based on the determined Reynolds number Re and flow coefficient C under different operating conditions d Establish flow coefficient C d The relationship between Reynolds number Re and the Reynolds number Re.

[0042] This disclosure no longer determines the boundary layer thickness directly based on measurement point data, but instead first determines the total boundary pressure P of the boundary layer based on the measurement point data. tbl_cri and the total pressure P within the boundary layer tbl The radial distribution piecewise linear function, and then based on the determined boundary layer boundary total pressure P tbl_cri and the total pressure P within the boundary layer tbl The radial distribution piecewise linear function is used to determine the boundary layer thickness δ. Since this boundary layer thickness δ determination process has taken into account the total pressure data between adjacent measuring points, it is less constrained by the distance between adjacent measuring points, which can reduce the deviation caused by the distance between adjacent measuring points, thereby obtaining a more accurate boundary layer thickness and effectively improving the accuracy of flow tube calibration results.

[0043] Other features and advantages of this disclosure will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0044] To more clearly illustrate the technical solutions in the embodiments of this disclosure or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the flow tube calibration device.

[0046] Figure 2 for Figure 1 A schematic diagram of the AA section.

[0047] Figure 3This is a schematic diagram illustrating the steps of the method in an embodiment of this disclosure.

[0048] Figure 4 This is a detailed schematic diagram of step S100 in an embodiment of this disclosure.

[0049] Figure 5 This is a logic block diagram of the method in the embodiments of this disclosure.

[0050] Explanation of reference numerals in the attached figures:

[0051] 1. Flow tube; 2. Measuring device; 21. Probe; 22. Boundary layer probe; 23. Mainstream probe; 24. Static pressure orifice. Detailed Implementation

[0052] The technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit this disclosure or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0053] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0054] In the description of this disclosure, it should be understood that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this disclosure.

[0055] Furthermore, the technical features involved in the different embodiments of this disclosure described below can be combined with each other as long as they do not conflict with each other.

[0056] Aero engines typically require aerodynamic testing to assess the aerodynamic performance of the entire engine or its components (such as the core engine or compressor). In aerodynamic testing of aero engines, flow meters (specifically called inlet flow meters) are generally used to measure flow rate and obtain flow parameters at the air inlet. To ensure accurate flow measurement during testing, the flow meter must be calibrated before use. Only calibrated flow meters can participate in aerodynamic testing.

[0057] Flowmeter calibration primarily includes two methods: bench calibration and online calibration. Bench calibration refers to calibrating the flowmeter on a flowmeter calibration bench. Online calibration, on the other hand, refers to calibrating the flowmeter while it is installed in the operating environment. Because bench calibration has limited coverage of flow ranges, and some flowmeters with higher flow ranges cannot be calibrated on existing calibration benches, and because calibration benches are costly to build, online calibration is more widely used. For flowmeters that are inconvenient to calibrate on a calibration bench, online calibration is generally used for pre-use calibration.

[0058] During the flow tube calibration process, a large amount of data will be measured, including total temperature, total pressure and static pressure data.

[0059] Total temperature refers to the temperature of a fluid when it is completely stationary through an adiabatic process, and its kinetic energy is converted into internal energy. In the aerospace field, total temperature refers to the stagnation temperature (also known as the critical temperature). Based on the total temperature, the static temperature can be calculated. Static temperature is the temperature measured when the thermometer is relatively stationary with respect to the airflow. In the aerospace field, static temperature refers to the temperature in front of the aircraft when there is no turbulent airflow. Total temperature is usually expressed in T. t The static temperature is usually represented by T. s express.

[0060] Static pressure refers to the pressure exerted on the surface of an object when it is at rest or in uniform linear motion. In the context of a flow meter, static pressure refers to the pressure measured on the wall of the flow meter. Static pressure is usually expressed in P. s express.

[0061] Total pressure, also known as stagnation pressure, refers to the pressure of an airflow when its velocity is isentropically reduced to zero. It is the sum of static and dynamic pressures in the airflow. Total pressure is usually denoted by P. t express.

[0062] When gas flows through a flow tube, a certain velocity gradient exists. The region near the wall where the gas velocity is lower is called the boundary layer; the region inside the flow tube outside the boundary layer is called the main flow region. Both the boundary layer and the main flow region are fluid mechanics terms. The boundary layer, also known as the boundary layer, refers to a layer of fluid adhering to the surface of a solid. The main flow region is the flow region outside the boundary layer and beyond the vortex regions formed by boundary layer detachment. Abstractly speaking, the boundary layer and the main flow region can be roughly considered as the tube wall and the cavity of a hollow tube, respectively. When measuring a flow tube, a large amount of total pressure data is obtained, including both the total pressure data within the boundary layer and the total pressure data within the main flow region. For ease of distinction, the total pressure data within the boundary layer is denoted by P. tbl The total pressure data within the mainstream area is represented by P. t0Similarly, for other parameters such as gas velocity v and density ρ, the corresponding parameters of the boundary layer and the main flow region are distinguished by adding bl and 0 to the subscripts, respectively.

[0063] In order to achieve the total temperature T of the flow tube t Total pressure P t and static pressure P s For measuring fluid parameters, a measuring device is usually installed on the flow tube to form a calibration device.

[0064] Figure 1 and Figure 2 An exemplary calibration device for flow tube calibration is shown.

[0065] like Figure 1-2 As shown, the calibration device includes a flow tube 1 and a measuring device 2. The measuring device 2 is installed at the measuring section of the flow tube 1 to measure the fluid parameters at that section. The measuring section is typically circular. Figure 1 In the diagram, section AA is the measurement section.

[0066] Among them, the flow tube 1 is generally a reducing pipe, and the cross section at its minimum diameter (i.e., the throat) is usually used as the measuring cross section. In other words, the measuring device 2 is usually installed at the minimum cross section of the flow tube 1.

[0067] Measuring device 2 is used to measure the total temperature T at the measuring section. t Total pressure P t and static pressure P s Parameters such as these are measured. See, for example. Figure 2 The measuring device 2 includes a static pressure orifice 24 and a probe 21. The static pressure orifice 24 is used to measure the static pressure P. s Data. Probe 21 is used to measure total temperature T. t and total pressure P t Data, including the measured total pressure P t The data includes total pressure data P within the boundary layer. tbl This also includes the total pressure data P within the mainstream area. t0 Accordingly, probe 21 includes both boundary layer probe 22 and mainstream region probe 23. Boundary layer probe 22 is used to measure total pressure data within the boundary layer. Mainstream region probe 23 is used to measure total pressure data within the mainstream region. Since the boundary layer is located radially outside the mainstream region, therefore, as... Figure 2As shown, typically, the insertion depth (radial distance from the insertion position to the wall) of the boundary layer probe 22 is less than the insertion depth of the main flow probe 23. To ensure complete coverage of the boundary layer by the boundary layer probe 22, the actual insertion depth is usually greater than the estimated boundary layer thickness. Therefore, the boundary layer probe 22 measures both the total boundary layer pressure and the total main flow pressure. For example, if the estimated boundary layer thickness is 7 mm, the insertion depth of the boundary layer probe 22 might reach 15 mm.

[0068] Static pressure orifice 24, boundary layer probe 22, and main flow zone probe 23 are arranged circumferentially at intervals on the measurement section. The number of these three is not limited to one, but can also be two or more. For example, in... Figure 2 In the measurement section, there are 8 static pressure holes 24 on the pipe wall, and 3 main flow probes 23 and 1 boundary layer probe 22 are provided in the pipe cavity of the measurement section.

[0069] The types of probe 21 can vary.

[0070] For example, each probe 21 can be a single-function probe that measures only one of total temperature and total pressure, or a composite probe that can measure both total temperature and total pressure data simultaneously. Figure 2 In the middle, the boundary layer probe 22 and the main flow probe 23 are both composite probes, which can measure both total pressure data and total temperature data.

[0071] For example, probe 21 can be either a single-point probe or a comb-shaped probe. A single-point probe has only one sensing element on its shaft, driven by a moving mechanism. By moving radially under the drive of the moving mechanism, parameters at different radial positions within the tube can be measured. The distance the moving mechanism moves the single-point probe each time is called the step size. A comb-shaped probe is inserted into the tube and fixed. Multiple sensing elements are arranged radially at intervals on the shaft of the comb-shaped probe. These multiple sensing elements are used to measure parameters at different radial positions within the tube. Figure 2 In the middle, both boundary layer probe 22 and mainstream region probe 23 are comb-shaped probes.

[0072] Both single-point and comb-shaped probes measure parameters at multiple radial positions within the tube. Each measured radial position can be called a measuring point. There is a radial distance between any two adjacent measuring points. For a single-point probe, the radial distance between two adjacent measuring points is the step size of the probe as it moves under the drive of the moving mechanism. For a comb-shaped probe, the radial distance between two adjacent measuring points is the distance between two adjacent sensing parts.

[0073] In actual use, the insertion depth of each probe and the arrangement of each measuring point can be designed according to the diameter of the measuring section of the flow tube 1 to match the diameter of the measuring section, so that the measurement method has no requirements on the diameter of the flow tube and can be applied to the calibration of flow tubes with different diameters.

[0074] The total temperature T measured during the calibration process t Total pressure P t and static pressure P s The data needs further processing to obtain aerodynamic parameters such as Mach number, Reynolds number, and flow coefficient. Furthermore, based on the obtained total temperature T... t Total pressure P t and static pressure P s Obtaining the flow coefficients corresponding to different Mach number and / or Reynolds number ranges is the primary goal of flow tube calibration.

[0075] Mach number is an important dimensionless parameter in fluid mechanics that characterizes the compressibility of a fluid. It is denoted as Ma and is defined as the ratio of the gas velocity v at a point in the flow field to the local sound speed c at that point, i.e., Ma = v / c.

[0076] The Reynolds number (Re) is a dimensionless number used to characterize fluid flow. It distinguishes between laminar and turbulent flow and can also be used to determine the resistance experienced by an object flowing in a fluid. The formula for calculating the Reynolds number Re is: Where v, ρ, and μ are the fluid velocity, density, and viscosity coefficient, respectively, and D is a characteristic length; for example, if the fluid flows through a circular pipe, then D is the equivalent diameter of the pipe. It can be understood that when calibrating flow tube 1, D is the equivalent diameter of the measurement cross-section.

[0077] The flow coefficient meter is C d , is the actual flow rate m passing through the measured cross section. actual With ideal flow m ideal The ratio between them. Flow coefficient C dThis will affect the calculation results of the physical flow rate. An accurate Cd value will yield an accurate inlet physical flow rate for the aero-engine. Since the converted flow rate, a crucial performance parameter of the aero-engine, is directly related to the inlet physical flow rate, accurate inlet physical flow rate ensures the accuracy of the aero-engine's performance parameters. During aero-engine testing, performance parameters are displayed in real-time on the screen and serve as a vital basis for operational procedures. Accurate aero-engine performance parameters are of paramount importance. The inlet physical flow rate refers to the actual mass flow rate flowing into the test specimen from the inlet. The converted flow rate refers to the flow rate calculated by converting the compressor inlet physical flow rate to standard atmospheric conditions (i.e., total pressure 101325 Pa, total temperature 288.15 K) based on the total temperature and pressure of the inlet airflow during compressor testing.

[0078] Based on the flow coefficient C d As can be seen from the concept, the flow coefficient C d The calculation formula is Wherein, ideal flow m ideal The ideal flow rate can be calculated directly using the formula: Since the diameter D of the flowmeter tube is constant, the ideal flow rate m through the flowmeter tube under a certain operating condition is obtained. ideal It is a constant value. Actual flow rate m actual Obtaining it is more complex, involving two parts: mainstream area traffic m main and the flow rate m within the boundary layer BL Among them, the mainstream area traffic m main and the flow rate m within the boundary layer BL All are related to the boundary layer thickness δ. Therefore, the actual flow rate m actual When performing calculations, it is necessary to first determine the boundary layer thickness δ.

[0079] It is evident that the boundary layer thickness δ is a critical parameter for flow tube calibration, and its accuracy is paramount, directly affecting the accuracy of flow calibration results and consequently, the accuracy of aero-engine aerodynamic performance test results. Therefore, obtaining an accurate boundary layer thickness δ is the primary problem that flow tube calibration technology needs to solve.

[0080] In related technologies, the following calibration data processing method is typically used to determine the boundary layer thickness δ:

[0081] Compare the total boundary layer pressure data P obtained at each measuring point tbl Total pressure P in the mainstream region t0 Data, when the total pressure P at a certain measuring point within the boundary layer tbl The data is close to or equal to the total pressure P at the main measuring points in the mainstream area. t0When processing the data, this location is considered the boundary layer boundary, and the radial distance from the corresponding location to the wall is determined as the boundary layer thickness δ.

[0082] However, the above method does not consider the total pressure data between two adjacent measuring points, but directly determines the boundary layer thickness δ based on the total pressure data of the measuring points. Therefore, it will be constrained by the distance between two adjacent measuring points, such as the minimum step size of the single-point probe and the minimum allowable distance between the sensing parts of the comb probe. The measured boundary layer thickness δ is usually a multiple of the minimum step size or minimum distance. This will lead to poor accuracy of the determined boundary layer thickness δ, which will affect the accuracy of the flow tube calibration results and the accuracy of the aerodynamic test results.

[0083] To address the above issues, this disclosure proposes a novel data processing method for flow tube calibration. This method processes the data measured during flow tube calibration to obtain more accurate boundary layer thickness δ and flow rate m within the boundary layer. BL and flow coefficient C d Parameters such as flow tube calibration data processing method are also included. This method is particularly suitable for processing data obtained during online flow tube calibration. In this case, the flow tube calibration data processing method can be specifically referred to as the online flow tube calibration data processing method.

[0084] Figure 3-5 An exemplary method for processing flow tube calibration data of this disclosure is shown.

[0085] See Figure 3-5 The flow tube calibration data processing method provided in this disclosure includes steps S100 and S200.

[0086] Step S100 involves, based on the measured static pressure P at the cross-section of the flow tube... s and total pressure P t Data to determine the total boundary pressure P of the boundary layer. tbl_cri and the total pressure P within the boundary layer tbl A radially distributed piecewise linear function.

[0087] It is understandable that the total boundary pressure P of the boundary layer is... tbl_cri This refers to the total pressure at the boundary of the boundary layer, which is the total pressure value corresponding to the maximum thickness of the boundary layer. In other words, it is the total pressure P at the boundary of the boundary layer. tbl_cri The radial distance from the corresponding location to the wall is the boundary layer thickness δ. In other words, the radial distance from the boundary layer boundary to the wall is the boundary layer thickness δ. The total pressure P within the boundary layer... tbl The radially distributed piecewise linear function is the total pressure P within the boundary layer. tbl A piecewise linear function relating the radial height x from the wall can characterize the radial distribution of total pressure data within the boundary layer. Based on the total pressure P within the boundary layer...tbl The radially distributed piecewise linear function can be used to obtain total pressure data at any radial location within the boundary layer.

[0088] Next, in step S100, the total boundary pressure P of the boundary layer is determined. tbl_cri and the total pressure P within the boundary layer tbl The process of obtaining the radially distributed piecewise linear function will be further explained in turn.

[0089] As an example, see Figure 4 Step S100 applies the total boundary pressure P of the boundary layer. tbl_cri The determination process further includes steps S101, S102, S103 and S104.

[0090] Step S101 is to, based on the measured static pressure P s and the total pressure P in the mainstream area t0 Data is used to determine the Mach number Ma0 in the mainstream region.

[0091] Mach number Ma and total pressure P t and static pressure P s The relationship between them is shown in equation (1) below:

[0092]

[0093] Where k is the specific heat ratio, which is a constant; P t Total pressure; P s It is static pressure.

[0094] From equation (1), it can be seen that the Mach number Ma0 in the mainstream region can be calculated according to equation (2):

[0095]

[0096] Therefore, step S101 can be achieved by using the measured static pressure P s and the total pressure P in the mainstream area t0 Substitute the data into equation (2) to obtain the Mach number Ma0 in the mainstream region.

[0097] In actual measurements, multiple total pressure data are usually obtained in the mainstream region. In this case, the total pressure P in the mainstream region is calculated by substituting into formula (2) to obtain the Mach number Ma0 in the mainstream region. t0 The average total pressure data of all measuring points in the mainstream region obtained by probe 23 can be taken as the average total pressure P of the mainstream region. t0 Substitute into equation (2).

[0098] Step S102 is to determine the gas velocity v0 in the mainstream region based on the Mach number Ma0 in the mainstream region.

[0099] According to the concept of Mach number Ma, the gas flow velocity v and Mach number Ma have the following relationship:

[0100]

[0101] Where R is the air gas constant, T s It is at rest temperature.

[0102] Therefore, the formula for calculating the gas velocity v0 in the mainstream region is as follows:

[0103]

[0104] Among them, static temperature T s Based on the measured total temperature T t Confirmed, the calculation formula is:

[0105]

[0106] Therefore, step S102 can measure the total temperature T of the mainstream area. t0 Substituting the data and the Mach number Ma0 of the mainstream region determined in step S101 into equation (5), the static temperature T of the mainstream region is obtained. s0 The data, and then the obtained mainstream area static temperature T s0 Substituting the data and the Mach number Ma0 of the mainstream region determined in step S101 into equation (4), the gas velocity v0 of the mainstream region is calculated.

[0107] As can be seen, step S102 can be based on the Mach number Ma0 in the mainstream region and the measured total temperature T in the mainstream region. t0 Data, based on Mach number Ma and total pressure P t Between, the gas flow rate v and Mach number Ma, and the static temperature T s With total temperature T t The relationship between these equations allows for the determination of the gas velocity v0 in the mainstream region.

[0108] Step S103 is to determine the boundary layer boundary gas velocity v based on the mainstream gas velocity v0. tbl_cri .

[0109] Typically, the boundary layer boundary is determined when the gas velocity at the boundary layer boundary is 0.99 times the gas velocity in the mainstream region. Therefore, in step S103, the boundary layer boundary gas velocity v is determined based on the mainstream gas velocity v0. tbl_cri At this time, 0.99 times the mainstream gas velocity v0 can be used as the boundary gas velocity v of the boundary layer. tbl_cri That is, the boundary gas velocity v at the boundary layer. tbl_cri The calculation formula is:

[0110] v = 0.99v0 (6).

[0111] Step S104 is to determine the boundary gas velocity v based on the boundary layer. tbl_cri Determine the total boundary pressure P of the boundary layer. tbl_cri .

[0112] As mentioned earlier, there is a relationship between the gas flow velocity v and the Mach number Ma, and between the Mach number Ma and the total pressure P. t There exists a relationship between equation (3) and equation (1). Therefore, at the boundary gas velocity v tbl_cri Once determined, the boundary gas velocity v at the boundary layer can be... tbl_cri Substitute the gas flow velocity v with the Mach number Ma and the Mach number Ma with the total pressure P t The calculation formula between them yields the total boundary pressure P of the boundary layer. tbl_cri .

[0113] Specifically, the boundary gas velocity v at the boundary layer determined in step S103 can be used as a reference. tbl_cri And the static temperature T determined based on equation (5) s Substituting into equation (3), we obtain the boundary layer boundary Ma number Ma. bl_cri Then, the obtained boundary layer boundary Mach number Ma bl_cri and the measured static pressure P s Total pressure P of boundary layer tbl Substituting the data into equation (1), we obtain the total boundary pressure P of the boundary layer. tbl_cri In this process, the total boundary layer pressure P in equation (1) is substituted. tbl The average value of the total pressure data at each measuring point measured by the boundary layer probe 22 can be taken.

[0114] As can be seen, based on steps S101, S102, S103, and S104, step S100 can be based on the measured static pressure P. s Total pressure P t and total temperature T t Data to achieve the total pressure P at the boundary of the boundary layer. tbl_cri The determination.

[0115] In addition, as mentioned above, step S100 can be based on the measured static pressure P. s and total pressure P t Data to determine the total boundary pressure P of the boundary layer. tbl_cri It can also be based on the measured static pressure P s and total pressure P t Data to determine the total pressure P within the boundary layer. tbl A radially distributed piecewise linear function.

[0116] As an example, step S100 applies the total pressure P within the boundary layer. tbl The process of determining the radially distributed piecewise linear function further includes:

[0117] Based on the measured static pressure P s and the total pressure P at each measuring point t Based on the data and the assumption that the total pressure between two radially adjacent measuring points within the boundary layer is linearly distributed, the total pressure P within the boundary layer is established. tbl The piecewise linear function of the radial distribution is:

[0118]

[0119] Where Δ is the radial distance between two adjacent total pressure measuring points on the flow tube measuring section; x is the radial height from the wall, which represents the radial coordinate of each radial position when the wall is the starting point; i is the sequence number of each measuring point arranged sequentially along the direction from the wall to the center, that is, i represents the i-th measuring point from the wall during the total pressure measurement process.

[0120] The total pressure P within the aforementioned boundary layer tbl In determining the piecewise linear function of the radial distribution, an assumption was made regarding the total pressure distribution within the boundary layer. It was assumed that the total pressure between two radially adjacent measuring points during the boundary layer measurement process exhibits a linear distribution. Under this linear assumption, the total pressure data of any two radially adjacent measuring points within the boundary layer lie on a straight line. Thus, for any two radially adjacent measuring points, a straight line can be obtained with i as the abscissa and the total pressure data of the two measuring points as the ordinate. It is assumed that this straight line satisfies P... tbl =ax + b, then substituting the total pressure data corresponding to two adjacent measuring points into the equation yields two constants a and b, which are respectively... and (1+i)P tbl(i) -iP tbl(i+1) Thus, this process is performed on every two adjacent total pressure measurement points, resulting in the above equation (7). Specifically, equation (7) is a piecewise linear function, corresponding to several piecewise straight lines.

[0121] As mentioned earlier, the total pressure data measured by the boundary layer probe 22 may typically include not only the total pressure data within the boundary layer but also some total pressure data outside the boundary layer. In this case, during the establishment of equation (7), the boundary layer boundary total pressure P determined in step S100 can be used as a reference. tbl_cri To determine which of the total pressure data measured by boundary layer probe 22 belong to the boundary layer and which do not, for example, only the total pressure data P measured by boundary layer probe 22 that is less than the boundary layer boundary pressure can be considered. tbl_cri The total pressure measurement data is used as the total pressure data within the boundary layer, while the total pressure P measured by the boundary layer probe 22, which is greater than the boundary layer boundary total pressure P, is used. tbl_criThe total pressure measurement data can be excluded. Alternatively, the total pressure data measured by the boundary layer probe 22 can be left undifferentiated when establishing equation (7), and then differentiated when determining the boundary layer thickness δ later.

[0122] Based on equation (7), not only can the total pressure data at each measuring point in the boundary layer be obtained, but also the total pressure data at any radial position within the boundary layer can be obtained. In other words, by establishing the total pressure P within the boundary layer... tbl The radial distribution piecewise linear function allows the calibration of flow tube 1 to extend beyond the total pressure data at any radial position within the boundary layer on the measurement cross section. This enables the analysis of the total pressure within the radial distance between two measurement points within the boundary layer. Consequently, the total pressure data is no longer limited by the radial distance between the two measurement points, or by the minimum step size of a single-point probe or the minimum distance between two measurement points of a comb probe. This allows for a more accurate determination of the total pressure within the boundary layer.

[0123] According to equation (7), the expression for the radial height x from the wall can be obtained as follows:

[0124]

[0125] As can be seen, step S100 can be based on the measured static pressure P s Total pressure P of boundary layer tbl Data, establish the total pressure P within the boundary layer tbl The relationship with the radial height x is used to determine the calculation model of the total pressure at any radial position within the boundary layer.

[0126] In summary, step S100 can be based on the measured static pressure P. s and total pressure P t Data to determine the total boundary pressure P of the boundary layer. tbl_cri and the total pressure P within the boundary layer tbl A radially distributed piecewise linear function.

[0127] Based on step S100, the boundary layer thickness δ can be further determined through step S200.

[0128] Among them, returning to Figure 3 Step S200 is to determine the total boundary pressure P of the boundary layer. tbl_cri and the total pressure P within the boundary layer tbl The radially distributed piecewise linear function is used to determine the boundary layer thickness δ.

[0129] Specifically, step S200, the process of determining the boundary layer thickness δ, further includes:

[0130] Based on the total pressure P in the boundary layer tblGiven a piecewise linear function with radial distribution, determine the expression for the radial height x from the wall. And based on the total boundary pressure P of the boundary layer tbl_cri Determine the measured total boundary layer pressure P. tbl The total pressure P at the boundary of the boundary layer in the data tbl_cri Two adjacent total pressure values ​​P tbl(i) and P tbl(i+1) And two total pressure values ​​P tbl(i) and P tbl(i+1) The corresponding measurement point numbers i and i+1;

[0131] The determined P tbl(i) P tbl(i+1) i, i+1 and the total boundary pressure P of the boundary layer tbl_cri Substitute into the formula The calculated x value is taken as the boundary layer thickness δ.

[0132] The above process involves first determining the total boundary pressure P of the boundary layer. tbl_cri The straight line where it lies, and then the total pressure P at the determined boundary layer boundary. tbl_cri Find the total boundary pressure P of the boundary layer on the straight line. tbl_cri The corresponding abscissa value, i.e., the total boundary pressure P of the boundary layer. tbl_cri The corresponding radial position. As analyzed above, the total boundary pressure P of the boundary layer... tbl_cri The corresponding radial position is the boundary layer boundary, and the radial distance from the boundary layer boundary to the wall is the boundary layer thickness δ. Therefore, the total boundary pressure P determined by the above process is... tbl_cri The corresponding abscissa value is the boundary layer thickness δ, which allows for the determination of the boundary layer thickness δ. The formula for calculating the boundary layer thickness δ can be expressed as follows:

[0133]

[0134] It can be seen that, based on steps S100 and S200, the total pressure distribution within the boundary layer and the boundary layer thickness δ can be determined.

[0135] Because of the above steps S100 and S200, the boundary layer thickness δ is no longer determined directly based on the measurement point data, but rather the total boundary pressure P of the boundary layer is determined first based on the measurement point data. tbl_cri and the total pressure P within the boundary layer tbl The radial distribution piecewise linear function, and then based on the determined boundary layer boundary total pressure P tbl_cri and the total pressure P within the boundary layer tblThe boundary layer thickness δ is determined by a piecewise linear function of radial distribution. This process of determining the boundary layer thickness δ takes into account the total pressure data between two adjacent measuring points. Therefore, it is less constrained by the distance between adjacent measuring points, which can reduce the deviation caused by the distance between adjacent measuring points. This results in a more accurate boundary layer thickness δ and effectively improves the accuracy of flow tube calibration results.

[0136] Based on the boundary layer thickness δ determined in step S200, the flow rate m within the boundary layer can be further determined. BL and mainstream area traffic m main In order to facilitate the determination of the flow coefficient C d .

[0137] Among them, see Figure 3 Based on the determined boundary layer thickness δ, the mass flow rate m within the boundary layer is determined. BL The step can be referred to as step S300. As an example, step S300 further includes:

[0138] Based on the determined boundary layer thickness δ, the mass flow rate m within the boundary layer is determined using an integral method. BL .

[0139] Specifically, the above steps include:

[0140] Based on the total pressure P within the boundary layer tbl The radial distribution piecewise linear function is used to determine the density ρ within the boundary layer. bl and gas velocity v in the boundary layer bl The relationship between the boundary layer toroidal area dS and the radial height x from the wall is obtained by integrating the expression and the relationship between the boundary layer toroidal area dS and the radial height x from the wall.

[0141] The density ρ within the boundary layer bl Gas velocity v in the boundary layer bl Substituting the expression relating the toroidal area dS of the boundary layer to the radial height x from the wall into the integral formula m BL =∑∫ρvdS, and take 0 and boundary layer thickness δ as the integral formulas respectively. BL The lower and upper limits of =∑∫ρvdS are used to obtain the mass flow rate m in the boundary layer. BL .

[0142] The formula for calculating density ρ is:

[0143]

[0144] The formula for calculating gas flow velocity v is:

[0145]

[0146] Therefore, the measured data within the boundary layer (e.g., the total pressure P within the boundary layer) will be used accordingly. tbl Substituting into equations (10) and (11) above, the density ρ within the boundary layer can be obtained. bl and gas velocity v in the boundary layer bl The calculation formulas are shown in equations (12) and (13) below:

[0147]

[0148]

[0149] Based on the total pressure P within the boundary layer tbl The radial distribution is a piecewise linear function, and the total pressure P within the boundary layer is... tbl It is a function of radial position x, therefore, the total pressure P within the boundary layer tbl Substituting the piecewise linear function of the radial distribution (Equation (7)) into Equations (12) and (13), the density ρ within the boundary layer can be obtained respectively. bl The relationship between x and the gas velocity v in the boundary layer bl The expression relating x.

[0150] The relationship between the boundary layer torus area dS and x is obtained by calculating the area of ​​the corresponding torus, that is:

[0151]

[0152] Where D is the equivalent diameter of the flow tube measuring section.

[0153] The flow rate within the torus at two adjacent boundary layer total pressure measurement points is a definite integral of the torus radial height. The flow rate within the boundary layer is the sum of the torus flow rates over the entire boundary layer thickness δ. Therefore, the mass flow rate m within the boundary layer is... BL The integral formula is:

[0154] m BL =∑∫ρvdS Equation (15).

[0155] The lower limit and upper limit of equation (15) are 0 and the boundary layer thickness δ, respectively. Therefore, to be precise, the mass flow rate m within the boundary layer is... BL The integral formula is

[0156] Therefore, the density ρ within the boundary layer bl Gas velocity v in the boundary layer bl Substituting the relationship between the boundary layer annular area dS and the radial height x from the wall into equation (15), and using 0 and the boundary layer thickness δ as the lower and upper limits of equation (15) respectively, the mass flow rate m within the boundary layer can be obtained. BL The calculation model realizes the calculation of mass flow rate m within the boundary layer.BL The determination.

[0157] Since this disclosure can determine the boundary layer thickness δ with relatively high accuracy, the above integration method can be used to determine the mass flow rate m within the boundary layer with relatively high accuracy. BL .

[0158] In addition, such as Figure 3 As shown, the mainstream flow rate m is determined based on the determined boundary layer thickness δ. main The step can be called step S400. Mainstream traffic m main The expression is:

[0159]

[0160] It can be seen that the mainstream area traffic m main It is also a function of the boundary layer thickness δ. Substituting the measured total pressure, total temperature, and static pressure data of the main flow area, along with the determined boundary layer thickness δ, into equation (16), the flow rate m in the main flow area can be obtained. main Since this disclosure can determine the boundary layer thickness δ with relatively high accuracy, step S400 can obtain the mainstream flow rate m with relatively high accuracy. main .

[0161] Based on the mass flow rate m within the boundary layer determined in steps S300 and S400 BL and mainstream area traffic m main The flow coefficient C can be obtained. d .

[0162] As mentioned earlier, the flow coefficient C d The calculation formula is:

[0163]

[0164] Where, m ide0l For the ideal flow rate, the calculation formula is:

[0165]

[0166] Therefore, the mass flow rate m within the boundary layer determined based on equations (15), (16), and (18) will be used. BL Mainstream traffic m m0in and ideal flow m ide0l Substituting into the above formula (17), the flow coefficient C can be established. d The calculation model realizes the calculation of the flow coefficient C. d The determination.

[0167] Based on the above process, see Figure 3In some embodiments, the flow tube calibration data processing method further includes:

[0168] S500, based on the determined mass flow rate m within the boundary layer. BL Determine the flow coefficient C d .

[0169] Specifically, step S500 includes:

[0170] Based on the measured static pressure P s Total temperature T t and total pressure P t Based on the data and the measured cross-sectional diameter D, the theoretical flow rate m is determined. ideal Based on the measured static pressure P s Total temperature T t and total pressure P t Based on the data, the cross-sectional diameter D, and the boundary layer thickness δ, the flow rate m in the main flow zone is determined. main ;

[0171] Based on the determined mass flow rate m within the boundary layer BL Theoretical flow rate m ideal and mainstream area traffic m main Determine the flow coefficient C d .

[0172] Due to the mass flow rate m within the boundary layer determined in this disclosure BL and mainstream area traffic m main All are relatively accurate; therefore, the determined flow coefficient C d It is also relatively accurate, which makes the calibration result of flow tube 1 more accurate, which is conducive to obtaining more accurate aerodynamic performance parameters.

[0173] Furthermore, embodiments of this disclosure are also based on the determined flow coefficient C. d Establish the flow coefficient C under different operating conditions d With Mach number Ma and / or flow coefficient C d The relationship between Reynolds number Re and the Reynolds number Re.

[0174] Here, "different operating conditions" refers to the different intake conditions during the calibration process. During calibration, due to the different rotational speeds of the test piece, the gas flow state at the measurement section of the flow tube 1 will differ, and correspondingly, the static pressure P will change. s Total temperature T t and total pressure P t The data will change. These different intake conditions are called different operating conditions, corresponding to different Mach numbers (Ma), Reynolds numbers (Re), and flow coefficients (C). d Establish the flow coefficient C under different operating conditions. d The relationship with Mach number Ma and the flow coefficient Cd By obtaining the relationship between the flow rate and the Reynolds number Re, the flow coefficients corresponding to different Mach number and Reynolds number ranges can be obtained, which is beneficial to better study the aerodynamic performance of the flow tube 1, and thus better study the aerodynamic performance of the test piece.

[0175] In some embodiments, the flow coefficient C d The relationship between Mach number Ma and Ma is determined as follows:

[0176] Based on the measured static pressure P under different working conditions s Total temperature T t and total pressure P t Data was used to determine the Mach number Ma and flow coefficient C under different operating conditions. d ;

[0177] Based on the determined Mach number Ma and flow coefficient C under different operating conditions d Establish flow coefficient C d The relationship between Mach number Ma and the expression.

[0178] As mentioned earlier, the formula for calculating the Mach number Ma is equation (1). Based on the determined Mach number Ma and flow coefficient C under different operating conditions... d The flow coefficient C can be established by fitting. d The relationship between Mach number Ma and the expression.

[0179] Considering the boundary layer Mach number Ma bl Compared to the mainstream Mach number Ma0, it is relatively small; therefore, when establishing the flow coefficient C... d The relationship between Mach number Ma and (C) d When -Ma), only the flow coefficient C needs to be established. d The relationship between the Mach number Ma0 in the mainstream region (C) d -Ma0).

[0180] Additionally, in some embodiments, the flow coefficient C d The relationship between Reynolds number Re and the Reynolds number Re is determined as follows:

[0181] Based on the measured static pressure P under different working conditions s Total temperature T t and total pressure P t Data was used to determine the Reynolds number (Re) and flow coefficient (C) under different operating conditions. d ;

[0182] Based on the determined Reynolds number Re and flow coefficient C under different operating conditions d Establish flow coefficient C d The relationship between Reynolds number Re and the Reynolds number Re.

[0183] As mentioned earlier, the formula for calculating the Reynolds number Re is:

[0184]

[0185] Where μ is the air viscosity coefficient of the measurement section, calculated as follows:

[0186]

[0187] Based on the determined Reynolds number Re and flow coefficient C under different operating conditions d The flow coefficient C is established by using a fitting method. d The relationship between Reynolds number Re and the Reynolds number Re.

[0188] Since the diameter of the main flow region (D-2δ) of the measuring section is relatively close to the diameter D of the measuring section, and the velocity v0 of the main flow region is similar to the average velocity v of the measuring section... 平均 The difference is small. According to the Reynolds number formula (19), the Reynolds number Re at the measurement section and the Reynolds number Re0 in the mainstream region are relatively close. Therefore, when establishing the flow coefficient C d The relationship between Reynolds number Re and (C) d When -Re), only the flow coefficient C needs to be established. d The relationship between the Reynolds number Re0 and the mainstream region (C) d -Re0).

[0189] In summary, the flow tube calibration data processing method provided in this disclosure constructs the total pressure P within the boundary layer based on the linear assumption of total pressure distribution between two radially adjacent measuring points and the judgment rule that the gas velocity at the boundary layer boundary is 0.99 times the gas velocity in the mainstream region. tbl The radial distribution piecewise linear function (Equation (7)) and the boundary layer thickness δ and the flow rate m in the boundary layer BL The calculation model (i.e., equations (9) and (15)) allows the boundary layer thickness δ and the flow rate m within the boundary layer to be obtained by substituting the total temperature, total pressure, and static pressure data measured during the calibration process into the model after the flow tube calibration is completed. BL And further calculate the flow coefficient C d .

[0190] After obtaining the boundary layer thickness δ, the flow rate m within the boundary layer is determined. BL During the process, based on the distance between two adjacent measuring points, it can be determined which boundary layer probe total pressure data are boundary layer total pressure data, and these data can be substituted into the boundary layer flow calculation model (Equation (15)) to obtain the boundary layer flow data.

[0191] Since the boundary layer thickness δ and the flow rate m within the boundary layer are determined... BLand flow coefficient C d During the process, the total pressure distribution between two adjacent measuring points of the probe was analyzed. Therefore, more accurate boundary layer thickness δ and boundary layer flow rate m can be obtained. BL and flow coefficient C d This allows for more accurate calibration of flow tube 1.

[0192] The above description is merely an exemplary embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A method for processing flow tube calibration data, characterized in that, include: Based on the measured static pressure at the flow tube measurement section and total pressure Data to determine the total boundary pressure of the boundary layer. and total pressure within the boundary layer A piecewise linear function with radial distribution; Based on the determined total boundary pressure of the boundary layer and total pressure within the boundary layer The radially distributed piecewise linear function is used to determine the boundary layer thickness. ; Among them, the static pressure at the measured cross-section of the flow tube is used as a basis. and total pressure Data to determine the total pressure within the boundary layer. The radially distributed piecewise linear functions include: Based on the measured static pressure and total pressure at each measuring point Based on the data and the assumption that the total pressure between two radially adjacent measuring points within the boundary layer is linearly distributed, the total pressure within the boundary layer is established. The piecewise linear function of the radial distribution is: in, The radial distance between two adjacent total pressure measuring points on the flow tube measuring section; This is the radial height from the wall surface; These are the serial numbers of the measuring points arranged sequentially from the wall to the center.

2. The flow tube calibration data processing method according to claim 1, characterized in that, The static pressure at the measured cross-section of the flow tube is based on the measured flow rate. and total pressure Data to determine the total boundary pressure of the boundary layer. include: Based on the measured static pressure and the total pressure of the mainstream area Data to determine the Mach number in the mainstream region ; Based on the Mach number of the mainstream region Determine the gas velocity in the mainstream region ; Based on the gas flow velocity in the mainstream area Determine the boundary gas velocity of the boundary layer. ; Based on the boundary gas velocity of the boundary layer Determine the total boundary pressure of the boundary layer. .

3. The flow tube calibration data processing method according to claim 2, characterized in that, The gas flow velocity based on the mainstream region Determine the boundary gas velocity of the boundary layer. include: With the gas flow rate in the mainstream region 0.99 times, as the boundary gas velocity of the boundary layer. .

4. The flow tube calibration data processing method according to claim 2, characterized in that, The boundary gas velocity based on the boundary layer Determine the total boundary pressure of the boundary layer. include: The boundary gas velocity of the boundary layer Substitute gas flow rate With Mach number Between and Mach number With total pressure The calculation formula between them yields the total boundary pressure of the boundary layer. ; Among them, gas flow rate With Mach number The calculation formula between them is: ,Mach number With total pressure The formula for calculating between them is Ma , For specific heat ratio, The gas constant of air. For static temperature, static temperature With total temperature The relationship between them is .

5. The flow tube calibration data processing method according to claim 1, characterized in that, The determined total boundary pressure of the boundary layer and total pressure within the boundary layer The radially distributed piecewise linear function is used to determine the boundary layer thickness. include: Based on the total pressure within the boundary layer The radially distributed piecewise linear function is used to determine the radial height from the wall. expression And according to the total pressure at the boundary of the boundary layer Determine the measured total boundary layer pressure The total pressure at the boundary of the boundary layer in the data Two adjacent total pressure values and and two total pressure values and Corresponding measuring point number and ; The determined , , , and the total pressure at the boundary of the boundary layer Substitute into the formula Calculated Value as boundary layer thickness .

6. The flow tube calibration data processing method according to any one of claims 1-5, characterized in that, The flow tube calibration data processing method further includes: Based on the determined boundary layer thickness Determine the mass flow rate within the boundary layer. .

7. The flow tube calibration data processing method according to claim 6, characterized in that, The determined boundary layer thickness Determine the mass flow rate within the boundary layer. include: Based on the determined boundary layer thickness The mass flow rate within the boundary layer is determined using an integral method. .

8. The flow tube calibration data processing method according to claim 7, characterized in that, The determined boundary layer thickness The mass flow rate within the boundary layer was determined using the integral method. include: Based on the total pressure within the boundary layer The radially distributed piecewise linear function is used to determine the density within the boundary layer. and gas velocity within the boundary layer radial height from the wall The relational expression is obtained, and the torus area of ​​the boundary layer is obtained by integration. radial height from the wall Relational expressions; Density within the boundary layer Gas velocity within the boundary layer and boundary layer toroidal area radial height from the wall Substitute the relational expression into the integral formula and with 0 and boundary layer thickness As integral formulas respectively The lower and upper limits are used to obtain the mass flow rate within the boundary layer. .

9. The flow tube calibration data processing method according to claim 7, characterized in that, The flow tube calibration data processing method further includes: Based on the determined mass flow rate within the boundary layer Determine the flow coefficient .

10. The flow tube calibration data processing method according to claim 9, characterized in that, The determined mass flow rate within the boundary layer Determine the flow coefficient include: Based on the measured static pressure Total temperature and total pressure Data and measured cross-sectional diameter Determine the theoretical flow rate Based on the measured static pressure Total temperature and total pressure Data, measured cross-sectional diameter and boundary layer thickness Determine the mainstream traffic area ; Based on the determined mass flow rate within the boundary layer Theoretical flow and mainstream traffic Determine the flow coefficient .

11. The flow tube calibration data processing method according to claim 9, characterized in that, The flow tube calibration data processing method further includes: Based on the measured static pressure under different working conditions Total temperature and total pressure Data to determine Mach number under different operating conditions and flow coefficient Based on the determined Mach numbers under different operating conditions and flow coefficient Establish flow coefficient With Mach number Relationships; and / or, Based on the measured static pressure under different working conditions Total temperature and total pressure Data to determine the Reynolds number under different operating conditions. and flow coefficient Based on the Reynolds numbers determined under different operating conditions and flow coefficient Establish flow coefficient With Reynolds number The relationship between them.

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