Method for calibrating inlet air flow tube of aero-engine

Abstract

The invention discloses an aero-engine inlet air flow tube calibration method, which comprises the following steps of S100, setting a measurement section MP0 at the front end of an air flow tube, and arranging atmospheric parameter measurement points for measuring atmospheric temperature, atmospheric humidity and atmospheric pressure in the measurement section MP0; a measuring section MP1 is arranged in the air flow pipe, wall surface static pressure measuring points and boundary layer probes are arranged in the measuring section MP1, the wall surface static pressure measuring points are arranged on the inner wall of the air flow pipe, the boundary layer probes are inserted into a flow channel of the air flow pipe, and the axial positions of the boundary layer probes relative to the wall surface static pressure measuring points are the same; s200, the effective mass flow of the air flow tube is calculated; s300, the boundary layer probe is dismounted, and then the theoretical mass flow of the air flow pipe is calculated; and S400, the flow coefficient is calculated according to the effective mass flow and the theoretical mass flow of the air flow tube. According to the invention, high-precision calibration of the air flow tube can be realized, the air flow measurement difficulty of an aero-engine inlet is effectively reduced, and the measurement precision is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of aeroengine inlet air flow measurement, and in particular, to a calibration method for an aeroengine inlet air flow tube. Background Art

[0002] The aeroengine inlet air flow is an important performance parameter of the engine, which directly affects the evaluation of other important parameters of the engine (such as the engine specific thrust, the fuel-air ratio in the combustion chamber, etc.), and is also an important input parameter for the correction of the overall engine performance scheme and the design of the aircraft inlet. It should be understood that the engine inlet air flow cannot be directly measured. Currently, in engine bench tests, it is generally calculated by measuring the total pressure, total temperature, static pressure and cross-sectional area of the throat of the vehicle inlet duct connected to the engine, or by measuring the total pressure, total temperature, static pressure of the throat of the vehicle inlet duct connected to the engine and combining with the inlet duct wind tunnel blowing test formula, or by interpolating the measured compressor pressure ratio and relative conversion speed on the compressor test characteristic diagram. At present, in China, the engine inlet air flow is mainly calculated by measuring the total pressure, total temperature, static pressure of the throat of the vehicle inlet duct connected to the engine and combining with the inlet duct wind tunnel blowing test formula. However, there is no high-precision calibration device for the aeroengine inlet air flow tube, and there are errors in the measurement data of the air flow tube, resulting in large errors in the finally calculated inlet air flow value, which does not conform to the actual parameters.

[0003] In response to this, Chinese invention patent CN115753112A provides an aeroengine inlet air flow measurement device with temperature compensation. By setting a heat exchange medium circulation heating or cooling system on the outer wall of the flow measurement tube, the heated or cooled heat exchange medium flows through the straight section wall surface of the flow measurement tube repeatedly, realizing the way of heat exchange between the circulating heat exchange medium and the measurement tube wall surface in real time, timely adjusting the temperature of the straight section wall surface of the measurement tube, avoiding the drastic fluctuation of the straight section temperature, and overcoming the large area measurement error caused by the influence of thermal expansion and contraction of the cross-section of the flow measurement tube, thus solving the problem of inaccurate flow measurement caused by the drastic change of the inlet air temperature on the flow tube. However, this solution mainly reduces the measurement error caused by the change of the cross-sectional area of the flow tube by adjusting the temperature of the straight section wall surface, and cannot achieve the accurate measurement of the aeroengine inlet air flow. Moreover, it is necessary to set a heat exchange medium circulation heating or cooling system on the outer wall of the flow measurement tube, and the test device has a complex structure and a high cost.

[0004] Secondly, Chinese invention patent CN116337189A provides a test device capable of calibrating the intake air flow of an aeroengine, including: an air flow path assembly, a support assembly for supporting the air flow path assembly, and an engine docked with the tail end of the air flow path assembly; the air flow path assembly sequentially includes an intake air flow tube, a straight tube measurement section, a diffuser adapter section, a diffuser section, a front pressure stabilization section, a nozzle group installation section, a rear pressure stabilization section, a contraction section, a short straight section, and a bellmouth adapter section from the head end to the tail end; a plurality of critical flow Venturi nozzles for measuring the flow rate are installed in the nozzle group installation section, each critical flow Venturi nozzle has an air flow path, and an electromagnetic valve for controlling the switch of the air flow path is arranged in the air flow path. By controlling the switches of critical flow Venturi nozzles with different quantities and positions, the size of the air flow rate of the air flow path assembly is changed; the flow rate measured by the straight tube measurement section is calibrated by the standard flow rate measured through the nozzle group installation section. This test device is also relatively complex, requiring the test bench to have a sufficiently large space to place the aeroengine intake air flow calibration test device, with high manufacturing costs and test costs. Moreover, for a turboprop engine full-scale test bench, the front end of the engine generally needs to be connected to a dynamometer, and the intake air flow calibration test device provided by this solution cannot be installed.

[0005] In addition, Chinese invention patent CN109506744A provides a method for calibrating the air flow rate of a critical flow Venturi nozzle group for aeroengine full-scale tests. A parallel combined critical flow Venturi nozzle group calibration device is installed in the intake air pressure stabilization chamber of a high-altitude test bench. The nozzle group consists of multiple Venturi nozzles with equal throat areas, and a partition is installed in a circumferentially uniform and embedded manner. The number of nozzles is determined according to the air supply capacity of the high-altitude test bench air supply source and the throttling characteristics of the main engine under test; the overall calibration device is connected to the pressure stabilization chamber using a flange structure, and rectifying grids are installed before and after the calibration device. The air flow rate test layout is carried out according to the requirements of a standard single critical flow Venturi nozzle; under given pressure conditions, according to the actual calibrated air flow rate, the opening and closing quantity of the nozzles is adjusted in a remote control manner, and the nozzles are put into use in the order of first the periphery and then the middle; the same calibrated air flow rate is calibrated by adjusting both the number of nozzles and the pressure ratio upstream and downstream of the nozzles. The standard air flow rate at each calibration point is the sum of the air flow rates measured by the opened nozzles. However, this solution relies on the test capabilities of a high-altitude test bench to calibrate the engine air flow rate by installing a parallel combined critical flow Venturi nozzle group calibration device in the intake air pressure stabilization chamber of the high-altitude test bench. The test costs are relatively high, and due to the shortage of high-altitude test bench test resources, it is not applicable to the measurement of the intake air flow rates of most engines. Summary of the Invention

[0006] The present invention provides a method for calibrating an aeroengine intake air flow tube to solve the technical problem that the existing air flow tubes cannot achieve high-precision calibration, resulting in the need to use complex devices to measure the aeroengine intake air flow rate.

[0007] According to one aspect of the present invention, there is provided a calibration method for the inlet air flow tube of an aeroengine, comprising the following steps:

[0008] S100: Set a measurement section MP0 at the front end of the air flow tube, and arrange atmospheric parameter measurement points for measuring atmospheric temperature, atmospheric humidity and atmospheric pressure within the measurement section MP0; and set a measurement section MP1 within the air flow tube, and arrange wall static pressure measurement points and boundary layer probes within the measurement section MP1, where the wall static pressure measurement points are arranged on the inner wall of the air flow tube, and the boundary layer probes are inserted into the flow channel of the air flow tube and have the same axial position relative to the wall static pressure measurement points;

[0009] S200: Calculate the effective mass flow rate of the air flow tube based on the measurement parameters of the atmospheric parameter measurement points, the wall static pressure measurement points and the boundary layer probes;

[0010] S300: Remove the boundary layer probes, and then calculate the theoretical mass flow rate of the air flow tube based on the measurement parameters of the atmospheric parameter measurement points and the wall static pressure measurement points;

[0011] S400: Calculate the flow coefficient cd of the air flow tube according to the following formula:

[0012]

[0013] where, is the effective mass flow rate of the air flow tube, is the theoretical mass flow rate of the air flow tube.

[0014] Preferably, step S200 specifically includes calculating the effective mass flow rate of the air flow tube using the following formula

[0015]

[0016] S5 i The calculation formula of is:

[0017]

[0018] S6 i The calculation formula of is:

[0019]

[0020]

[0021] S7 i The calculation formula of is:

[0022]

[0023] where i is the radial measurement point of the boundary layer probe, r i is the radius of the radial measurement point i, c i is the gas velocity at the radial measurement point i, ρ i is the gas density at the radial measurement point i.

[0024] Preferably, the gas velocity c at the radial measurement point i i is calculated using the following formula:

[0025] c i = Ma i，MP1 * a i，MP1

[0026] where Ma i，MP1 is the Mach number at the radial measurement point i in the measurement section MP1, a i，MP1 is the local speed of sound at the radial measurement point i in the measurement section MP1;

[0027]

[0028] where κ mix is the specific heat ratio, R mix is the gas parameter, T s，i，MP1 is the static temperature at the radial measurement point i in the measurement section MP1, T t，MP0 is the total temperature of the measurement section MP0, P t，i，MP1 is the total pressure of the measurement section MP1, P s，MP1 is the wall static pressure of the air flow tube at the measurement section MP1.

[0029] Preferably, when the ambient temperature of the air flow tube is not 20 °C, the radius r of the radial measurement point i i is corrected using the following formula:

[0030] r i = r geo，20℃ * (1 + α 材料 * (T t，MP0 [K] - 293.15K))

[0031] where r geo，20 °C is the radius of the radial measurement point i at an ambient temperature of 20 °C, α 材料 is the expansion coefficient of the material of the air flow tube, T t，MP0 is the total temperature of the measurement section MP0.

[0032] Preferably, the gas density ρ at the radial measurement point i i is calculated using the following formula:

[0033]

[0034] Among them, p s，i = p s，MP1 , P s，MP1 is the static wall pressure of the air flow tube at the measurement section MP1, T s，i，MP1 is the static temperature at the radial measurement point i in the measurement section MP1, R mix is the gas constant.

[0035] Preferably, step S300 specifically includes calculating the theoretical mass flow rate of the air flow tube using the following formula

[0036]

[0037] Among them, A geo，corrected(T) is the aerodynamic area of the air flow tube, ρ MP1 is the air density at the measurement section MP1, c MP1 is the air flow velocity at the measurement section MP1.

[0038] Preferably, when the ambient temperature of the air flow tube is not 20 °C, the aerodynamic area A geo，corrected(T) of the air flow tube is corrected using the following formula:

[0039] A geo，corrected(T) = A geo，20℃ *(1 + α 材料 *(T t，MP0 - 293.15)) 2

[0040] Among them, A geo，20℃ is the aerodynamic area of the air flow tube at an ambient temperature of 20 °C, α 材料 is the expansion coefficient of the material of the air flow tube, T t，MP0 is the total temperature of the measurement section MP0.

[0041] Preferably, the air density ρ MP1 at the measurement section MP1 is calculated using the following formula:

[0042]

[0043] Among them, P s，MP1 is the static wall pressure of the air flow tube at the measurement section MP1, R mix is the gas constant, T S，MP1 is the static temperature of the measurement section MP1.

[0044] Preferably, the static temperature T S，MP1 at the measurement section MP1 is calculated using the following formula:

[0045]

[0046] T t，MP1 For measuring the total temperature of the measurement section MP1, which is equal to the total temperature of the measurement section MP0, and is obtained by measuring through the atmospheric parameter measurement points;

[0047] P t，MP1 For measuring the total pressure of the measurement section MP1, which is equal to the total pressure of the measurement section MP0, and is obtained by measuring through the atmospheric parameter measurement points;

[0048] P s，MP1 For measuring the static pressure of the measurement section MP1, which is obtained by measuring through the wall static pressure measurement points.

[0049] Preferably, the air flow velocity c of the measurement section MP1 MP1 is calculated using the following formula:

[0050] c MP1 = Ma t h ，MP1 * a MP1

[0051] Ma th，MP1 is the theoretical Mach number of the measurement section MP1, and is calculated using the following formula:

[0052]

[0053] a MP1 is the local speed of sound of the measurement section MP1, and is calculated using the following formula:

[0054]

[0055] where κ mix is the specific heat ratio, P t，MP1 is the total pressure of the measurement section MP1, P S，MP1 is the static pressure of the measurement section MP1, R mix is the gas constant, T S，MP1 is the static temperature of the measurement section MP1.

[0056] The present invention has the following beneficial effects:

[0057] The calibration method for the air inlet flow tube of an aeroengine provided by the present invention corrects the aerodynamic area of the air flow tube by reasonably arranging measurement sections on the air flow tube, measuring the atmospheric temperature, atmospheric humidity, and atmospheric pressure at the front end of the air flow tube, measuring the wall static pressure of the air flow tube using wall static pressure measurement points, and setting boundary layer probes at the same axial position as the relative wall static pressure measurement points to measure the boundary layer thickness of the measurement section MP1 in real time. When boundary layer probes are installed on the air flow tube, the effective mass flow rate of the air flow tube can be calculated by calculating the corrected aerodynamic area, air density, and air flow velocity at the measurement section MP1; when boundary layer probes are not installed on the air flow tube, the theoretical mass flow rate of the air flow tube can be calculated by calculating the aerodynamic area, air density, and air flow velocity at the measurement section MP1. Finally, the flow coefficient of the air flow tube can be calculated by the ratio of the effective mass flow rate to the theoretical mass flow rate, thereby achieving high-precision calibration of the air flow tube. Furthermore, in subsequent air inlet flow measurement operations of the aeroengine, it is no longer necessary to install boundary layer probes, nor is it necessary to calculate the effective mass flow rate at the engine inlet through complex formulas. Only by setting wall static pressure measurement points to measure the theoretical mass flow rate at the engine inlet can the effective mass flow rate at the engine inlet be quickly converted through the flow coefficient, effectively reducing the measurement difficulty, improving the measurement accuracy, with a simple and efficient measurement structure and strong applicability.

[0058] In addition to the purposes, features, and advantages described above, the present invention has other purposes, features, and advantages. The following will refer to the drawings for a further detailed description of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The drawings constituting a part of this application are used to provide a further understanding of the present invention. The schematic embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0060] Figure 1 It is a diagram of the measurement section and the distribution position of the measurement points of the calibration method for the air inlet flow tube of the aeroengine provided by the embodiment of the present invention;

[0061] Figure 2 is Figure 1 a schematic diagram of the measurement point arrangement structure of the boundary layer probe on the air flow tube shown;

[0062] Figure 3 is Figure 2 a distribution diagram of the total pressure p i ) corresponding to different radial measurement points (corresponding to the radius r t，i ) in the boundary layer probe shown;

[0063] Figure 4 is Figure 2The air flow velocity c corresponding to different radial measurement points i in the boundary layer probe shown i (r) distribution diagram.

[0064] Legend:

[0065] 1. Air flow tube; 2. Atmospheric parameter measurement point; 3. Wall static pressure measurement point; 4. Boundary layer probe. Specific implementation manner

[0066] The embodiments of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention can be implemented in many different ways defined and covered by the following. Examples of the embodiments are shown in the drawings, where the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the drawings are exemplary and are only used to explain the present invention and should not be construed as a limitation of the present invention.

[0067] Those skilled in the art of the present technology can understand that, unless specifically stated, the term "including" used in the specification of the present invention means the presence of the described features, integers, steps, operations, components and / or assemblies, but does not exclude the presence or addition of one or more other features, integers, steps, operations, components, assemblies and / or their combinations. It should be understood that when we say that a component is "connected" to another component, it can be directly connected to other components or connected through intermediate components. The term "and / or" used here includes all or any unit and all combinations of one or more related listed items. The terms "first" and "second" etc. in the specification and claims of the present invention are used to distinguish different objects and not to describe a specific order.

[0068] Figures 1 to 4 Collectively show the calibration method for the air flow tube at the inlet of an aeroengine provided by the embodiments of the present invention. It is used to calibrate the air flow tube with high precision, pre-calculate the flow coefficient of the air flow tube, so that when the air flow tube is applied to the air flow measurement operation at the inlet of the aeroengine, the measured theoretical mass flow can be quickly converted into the effective mass flow, and the accurate inlet air flow can be obtained, providing data support for the evaluation of other important parameters such as the specific thrust of the aeroengine and the fuel-air ratio in the combustion chamber.

[0069] Please combine Figure 1 and Figure 2 , the calibration method for the air flow tube at the inlet of the aeroengine includes the following steps:

[0070] Step S100: Set a measurement section MP0 at the front end of the air flow tube 1, and arrange atmospheric parameter measurement points 2 for measuring atmospheric temperature, atmospheric humidity, and atmospheric pressure within the measurement section MP0; and set a measurement section MP1 within the air flow tube 1, and arrange a wall static pressure measurement point 3 and a boundary layer probe 4 within the measurement section MP1. The wall static pressure measurement point 3 is arranged on the inner wall of the air flow tube 1, and the boundary layer probe 4 is inserted into the flow channel of the air flow tube 1 and has the same axial position relative to the wall static pressure measurement point 3.

[0071] Step S200: Calculate the effective mass flow rate of the air flow tube 1 based on the measurement parameters of the atmospheric parameter measurement points 2, the wall static pressure measurement point 3, and the boundary layer probe 4.

[0072] Step S300: Remove the boundary layer probe 4, and then calculate the theoretical mass flow rate of the air flow tube 1 based on the measurement parameters of the atmospheric parameter measurement points 2 and the wall static pressure measurement point 3.

[0073] Step S400: Calculate the flow coefficient cd of the air flow tube 1 according to the following formula:

[0074]

[0075] where, is the effective mass flow rate of the air flow tube 1, is the theoretical mass flow rate of the air flow tube 1.

[0076] Specifically, in step S100, the boundary layer probe 4 includes a plurality of detection ports arranged at intervals along the radial direction of the air flow tube 1. The main body structure of the boundary layer probe 4 is installed on one side of the wall static pressure measurement point 3 and inserted into the flow channel of the air flow tube 1 along the radial direction from the side wall of the air flow tube 1. The detection ports of the boundary layer probe 4 are bent relative to the main body structure of the boundary layer probe 4 so that the detection ports are arranged along the axial direction of the air flow tube 1, thereby making the detection ports face the air flow direction. Moreover, the detection positions of the plurality of detection ports are all located on the measurement section MP1, that is, the detection positions of the plurality of detection ports and the wall static pressure measurement point 3 are all located at the same axial position of the air flow tube 1 to ensure the correspondence of the detection data of the wall static pressure measurement point 3 and the boundary layer probe 4. There are a plurality of the atmospheric parameter measurement points 2, and the plurality of atmospheric parameter measurement points 2 are respectively connected to an atmospheric parameter measuring device and are used to detect atmospheric temperature, atmospheric humidity, and atmospheric pressure one by one.

[0077] The calibration method for the inlet air flow tube of an aeroengine realizes high-precision calibration of the air flow tube 1 by reasonably arranging measurement sections on the air flow tube 1, measuring the atmospheric temperature, atmospheric humidity, and atmospheric pressure at the front end of the air flow tube 1, measuring the wall static pressure of the air flow tube 1 using the wall static pressure measuring point 3, and setting the boundary layer probe 4 at the same axial position as the relative wall static pressure measuring point 3 to measure the boundary layer thickness of the measurement section MP1 in real time, thereby enabling correction of the pneumatic area of the air flow tube 1. Specifically, when the boundary layer probe 4 is installed on the air flow tube 1, the effective mass flow rate of the air flow tube 1 can be calculated by calculating the corrected pneumatic area, air density, and air flow velocity at the measurement section MP1; when the boundary layer probe 4 is not installed on the air flow tube 1, the theoretical mass flow rate of the air flow tube 1 can be calculated by calculating the pneumatic area, air density, and air flow velocity at the measurement section MP1. Finally, the flow coefficient of the air flow tube 1 can be calculated by the ratio of the effective mass flow rate to the theoretical mass flow rate, thereby realizing high-precision calibration of the air flow tube 1. Furthermore, in subsequent inlet air flow measurement operations of the aeroengine, it is no longer necessary to install the boundary layer probe 4, nor is it necessary to calculate the effective mass flow rate at the engine inlet through complex formulas. Only by setting the wall static pressure measuring point 3 to measure the theoretical mass flow rate at the engine inlet can the effective mass flow rate at the engine inlet be quickly converted through the flow coefficient, effectively reducing the measurement difficulty, improving the measurement accuracy, with a simple and efficient measurement structure and strong applicability.

[0078] Further, cd = f(Ma th ),

[0079] Ma th is the theoretical Mach number, P t，MP0 is the total pressure of the measurement section MP0, P s，MP1 is the static pressure of the measurement section MP1, T t，MP0 is the total temperature of the measurement section MP0; is the humidity of the measurement section MP0, i.e., the atmospheric humidity; P amb , is the air pressure of the measurement section MP0, i.e., the atmospheric pressure; T amb is the temperature of the measurement section MP0, i.e., the atmospheric temperature; the above parameters are all measured values when the boundary layer probe 4 is not installed. The theoretical Mach number is a function of these parameters including the total pressure of the measurement section MP0, the static pressure of the measurement section MP1, the total temperature of the measurement section MP0, the atmospheric humidity, the atmospheric pressure, and the atmospheric temperature.

[0080] Preferably, step S200 specifically includes calculating the effective mass flow rate of the air flow tube 1 using the following formula

[0081]

[0082] S5 i The calculation formula for it is:

[0083]

[0084]

[0085] S6 i The calculation formula for it is:

[0086]

[0087] S7 i The calculation formula for it is:

[0088]

[0089] Where, i is the radial measurement point of the boundary layer probe 4, r i is the radius of the radial measurement point i, c i is the gas velocity at the radial measurement point i, ρ i is the gas density at the radial measurement point i.

[0090] S5 i , S6 i and S7 i The calculation assumptions for them are:

[0091] i is the radial measurement point (i = 0 to 11), and multiple radial measurement points are arranged in sequence along the radial direction of the air flow tube 1, r i＝0 = r Tip , r i＝11 = r Hub = 0 mm, that is, when i = 0, this radial measurement point is located on the inner wall of the air flow tube 1, and its radius is equal to the inner diameter of the air flow tube 1; when i = 11, this radial measurement point is located on the axis of the air flow tube 1, and its radius is zero;

[0092] p t，Tip，MP1 = p s，MP1 , the total pressure at the end of the boundary layer probe 4 is equal to the static pressure on the wall of the air flow tube 1;

[0093] As Figure 3 and Figure 4 shown, the approximate values of c i and ρ i are as follows:

[0094] The linear relationship between the velocities of two radial measurement points: c i (r) = a ci * r + b ci

[0095] Density linear relationship between two radial measurement points: ρ i (r) = a ρi *r + b ρi

[0096] The calibration method for the air flow tube at the inlet of the aeroengine can accurately calculate the effective mass flow rate of the air flow tube 1 by calculating the measurement data of multiple radial measurement points of the boundary layer probe 4, providing data support for the calculation of the flow coefficient, so as to accurately calibrate the air flow tube 1, which is beneficial to accurately measuring the effective mass flow rate at the inlet of the aeroengine.

[0097] Preferably, the gas velocity c at the radial measurement point i i is calculated using the following formula:

[0098] c i = Ma i，MP1 *a i，MP1

[0099] where Ma i，MP1 is the Mach number at the radial measurement point i in the measurement section MP1, and a i，MP1 is the local speed of sound at the radial measurement point i in the measurement section MP1;

[0100]

[0101] where κ mix is the specific heat ratio, R mix is the gas parameter, T s，i，MP1 is the static temperature at the radial measurement point i in the measurement section MP1, T t，MP0 is the total temperature of the measurement section MP0, P t，i，MP1 is the total pressure of the measurement section MP1, P s，MP1 is the wall static pressure of the air flow tube at the measurement section MP1; the total temperature T t，MP0 , the total pressure P t，i，MP1 and the wall static pressure P s，MP1 are all measured values and can be directly measured.

[0102] The calibration method for the air flow tube at the inlet of the aeroengine accurately calculates the gas velocity c at the radial measurement point i in the measurement section MP1 through the Mach number and the local speed of sound at the radial measurement point i i , and both the Mach number and the local speed of sound are accurately calculated from the measured parameters. Using the above formula can accurately calculate the gas velocity at each radial measurement point, ensuring the accuracy and reliability of the data.

[0103] Preferably, when the ambient temperature where the air flow tube 1 is located is not 20 °C, the radius r of the radial measurement point i iThe following formula is used for correction:

[0104] r i = r geo，20℃ *(1 + α 材料 *(T t，MP0 [K] - 293.15K))

[0105] Wherein, r geo，20℃ is the radius of the radial measurement point i at an ambient temperature of 20°C, α 材料 is the expansion coefficient of the material of the air flow tube 1, and T t，MP0 is the total temperature of the measurement section MP0.

[0106] Specifically, when the ambient temperature of the air flow tube 1 is 20°C, the radius c of the radial measurement point i of the boundary layer probe 4 i is equal to the theoretical value r geo，20℃ , and the value can be directly taken for calculation; when the ambient temperature of the air flow tube 1 is not 20°C, that is, when the inlet temperature of the air flow tube 1 is relatively low or high, the boundary layer probe 4 will be affected by the expansion or contraction of its own material, resulting in a change in the radius c of its radial measurement point i i . At this time, the actual radius can be accurately corrected by the above formula, effectively avoiding deviation of the detection data.

[0107] Preferably, the gas density ρ at the radial measurement point i i is calculated using the following formula:

[0108]

[0109] Wherein, p s，i = p s，MP1 , P s，MP1 is the wall static pressure of the air flow tube 1 at the measurement section MP1, T s，i，MP1 is the static temperature at the radial measurement point i in the measurement section MP1, and R mix is the gas constant. The wall static pressure P s，MP1 and the static temperature T s，i，MP1 are both measured values and can be directly measured.

[0110] Through the above formula, the gas density ρ at the radial measurement point i can be accurately calculated using the wall static pressure, static temperature and gas constant of the air flow tube 1 i . While ensuring the accuracy of the gas density, there is no need to additionally set a gas density detection device, which will not affect the air flow of the air flow tube and ensure the accuracy of the detection of other parameters.

[0111] Preferably, step S300 specifically includes calculating the theoretical mass flow rate of the air flow tube 1 using the following formula

[0112]

[0113] Among them, A geo，corrected(T) is the pneumatic area of the air flow tube 1, ρ MP1 is the air density at the measurement section MP1, and c MP1 is the air flow velocity at the measurement section MP1.

[0114] Theoretical mass flow rate The assumptions for the calculation are as follows:

[0115] The static pressure at the measurement section MP1 is constant throughout the radius and annulus of the measurement section MP1; the total temperature at the measurement section MP1 is constant throughout the radius and annulus of the measurement section MP1; the total temperature at the measurement section MP0 is the same as that at the measurement section MP1, and the gas parameters R mix and the specific heat capacity at constant pressure cp of humid air mix are the same.

[0116] The theoretical mass flow rate of the air flow tube 1 is calculated through the pneumatic area of the air flow tube 1, the air density at the measurement section MP1, and the air flow velocity at the measurement section MP1. The calculation method is simple and efficient, and the calculation difficulty is low.

[0117] Preferably, when the ambient temperature where the air flow tube 1 is located is not 20 °C, the pneumatic area A geo，corrected(T) of the air flow tube 1 is corrected using the following formula:

[0118] A geo，corrected(T) = A geo，20℃ *(1 + α 材料 *(T t，MP0 - 293.15)) 2

[0119] Among them, A geo，20℃ is the pneumatic area of the air flow tube 1 at an ambient temperature of 20 °C, α 材料 is the expansion coefficient of the material of the air flow tube 1, and T t，MP0 is the total temperature at the measurement section MP0.

[0120] Specifically, when the ambient temperature where the air flow tube 1 is located is 20 °C, the pneumatic area of the air flow tube 1 is equal to the theoretical value A geo，20℃ , and it can be directly used for calculation; when the ambient temperature where the air flow tube 1 is located is not 20 °C, that is, when the intake temperature of the air flow tube 1 is relatively low or high, the air flow tube 1 will be affected by the expansion or contraction of its own material, resulting in a change in its diameter. At this time, the actual pneumatic area of the air flow tube 1 can be accurately corrected through the above formula, effectively avoiding deviations in the detection data.

[0121] Preferably, the air density ρ of the measurement cross-section MP1 is measured MP1 using the following formula for calculation:

[0122]

[0123] where P s，MP1 is the static wall pressure of the air flow tube 1 at the measurement cross-section MP1, and R mix is the gas constant, and T S，MP1 is the static temperature of the measurement cross-section MP1. The static wall pressure P s，MP1 and the static temperature T S，MP1 are both measured values and can be directly measured.

[0124] Through the above formula, the air density ρ of the measurement cross-section MP1 can be accurately calculated using the static wall pressure, static temperature, and gas constant of the air flow tube 1 MP1 , ensuring the accuracy of the air density without the need to additionally set up a gas density detection device, without affecting the air flow of the air flow tube, and ensuring the accuracy of the detection of other parameters.

[0125] Furthermore, the gas parameter R mix is calculated using the following formula:

[0126]

[0127] where R air is the adiabatic index of air; R water is the adiabatic index of water; x H20 is the specific humidity, which refers to the ratio of the mass of water vapor in a mass of air to the total mass of the air mass, and are respectively:

[0128]

[0129] where P H20，sat. is the saturated water vapor pressure, T amb is in the unit of °C.

[0130] The gas parameter R mix is accurately calculated using the above formula, ensuring accurate calculation.

[0131] Preferably, the static temperature T of the measurement cross-section MP1 S，MP1 is calculated using the following formula:

[0132]

[0133] T t，MP1 is the total temperature of the measurement cross-section MP1, equal to the total temperature of the measurement cross-section MP0, and is measured through the atmospheric parameter measurement point 2;

[0134] P t，MP1 The total pressure of the measurement section MP1, which is equal to the total pressure of the measurement section MP0, is measured through the atmospheric parameter measurement point 2;

[0135] P s，MP1 The static pressure of the measurement section MP1 is measured through the wall static pressure measurement point 3.

[0136] κ mix is the specific heat ratio and is calculated using the following formula:

[0137]

[0138] where Cp air is the specific heat at constant pressure of air; CP water is the specific heat at constant pressure of water.

[0139] The calibration method for the inlet air flow tube of the aeroengine accurately calculates the static temperature T of the measurement section MP1 through the total temperature, total pressure, and static pressure of the measurement section MP1 S，MP1 , ensuring the accuracy and reliability of the static temperature data.

[0140] Preferably, the air flow velocity c of the measurement section MP1 MP1 is calculated using the following formula:

[0141] c MP1 = Ma th，MP1 * a MP1

[0142] Ma th，MP1 is the theoretical Mach number of the measurement section MP1 and is calculated using the following formula:

[0143]

[0144] a MP1 is the local speed of sound of the measurement section MP1 and is calculated using the following formula:

[0145]

[0146] where κ mix is the specific heat ratio, P t，MP1 is the total pressure of the measurement section MP1, P S，MP1 is the static pressure of the measurement section MP1, R mix is the gas constant, T S，MP1 is the static temperature of the measurement section MP1.

[0147] The calibration method of the inlet air flow tube of the aeroengine first accurately calculates the theoretical Mach number and the local speed of sound of the measurement section MP1 through the above formula, and then calculates the air flow velocity c of the measurement section MP1 by combining the theoretical Mach number and the local speed of sound MP1 , and the calculation method is simple and efficient, ensuring the accuracy of the calculation results.

[0148] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various changes and modifications. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A calibration method for the inlet air flow tube of an aeroengine, characterized in that, Including the following steps: S100: Set a measurement section MP0 at the front end of the air flow tube (1), and arrange atmospheric parameter measurement points (2) for measuring atmospheric temperature, atmospheric humidity and atmospheric pressure within the measurement section MP0; and set a measurement section MP1 within the air flow tube (1), and arrange a wall static pressure measurement point (3) and a boundary layer probe (4) within the measurement section MP1. The wall static pressure measurement point (3) is arranged on the inner wall of the air flow tube (1), and the boundary layer probe (4) is inserted into the flow channel of the air flow tube (1) and has the same axial position relative to the wall static pressure measurement point (3); S200: Calculate the effective mass flow rate of the air flow tube (1) according to the measurement parameters of the atmospheric parameter measurement points (2), the wall static pressure measurement points (3) and the boundary layer probe (4); S300: Remove the boundary layer probe (4), and then calculate the theoretical mass flow rate of the air flow tube (1) according to the measurement parameters of the atmospheric parameter measurement points (2) and the wall static pressure measurement points (3); S400: Calculate the flow coefficient cd of the air flow tube (1) according to the following formula: wherein, is the effective mass flow rate of the air flow tube (1), is the theoretical mass flow rate of the air flow tube (1).

2. The calibration method of the inlet air flow tube of an aeroengine according to claim 1, wherein Step S200 specifically includes calculating the effective mass flow rate of the air flow pipe (1) using the following formula S5 i The calculation formula of S6 i The calculation formula is as follows: S7 i The calculation formula is as follows: Among them, i is the radial measurement point of the boundary layer probe (4), r i is the radius of the radial measurement point i, c i is the gas velocity at the radial measurement point i, ρ i is the gas density at the radial measurement point i.

3. The calibration method of the inlet air flow tube of an aeroengine according to claim 2, characterized in that The gas velocity c at the radial measurement point i i is calculated using the following formula: c i = Ma i，MP1 * a i，MP1 Among them, Ma i，MP1 is the Mach number at the radial measurement point i in the measurement section MP1, and a i，MP1 is the local speed of sound at the radial measurement point i in the measurement section MP1; where κ mix is the specific heat ratio, R mix is the gas parameter, T s，i，MP1 is the static temperature at the radial measurement point i in the measurement section MP1, T t，MP0 is the total temperature of the measurement section MP0, P t，i，MP1 is the total pressure of the measurement section MP1, P s，MP1 is the wall static pressure of the air flow tube (1) at the measurement section MP1.

4. The calibration method for the inlet air flow tube of an aeroengine according to claim 2, characterized in that, When the ambient temperature where the air flow tube (1) is located is not 20 °C, the radius r of the radial measurement point i i is corrected using the following formula: r i = r geo，20 °C * (1 + α 材料 * (T t，MP0 [K] - 293.15 K)) where r geo，20 ℃ is the radius of the radial measurement point i at an ambient temperature of 20 °C, and α 材料 is the expansion coefficient of the material of the air flow tube (1), and T t，MP0 is the total temperature of the measurement section MP0.

5. The calibration method of the inlet air flow tube of an aeroengine according to claim 2, characterized in that, The gas density ρ at the radial measurement point i i is calculated using the following formula: where p s，i = p s，MP1 , P s，MP1 is the static wall pressure of the air flow tube (1) at the measurement section MP1, T s，i，MP1 is the static temperature at the radial measurement point i in the measurement section MP1, and R mix is the gas constant.

6. The calibration method for the inlet air flow tube of an aeroengine according to claim 1, characterized in that, Step S300 specifically includes calculating the theoretical mass flow rate of the air flow pipe using the following formula Among them, A geo，corrected(T) is the pneumatic area of the air flow tube (1), ρ MP1 is the air density of the measurement section MP1, c MP1 is the air flow velocity of the measurement section MP1.

7. The calibration method for the inlet air flow tube of an aeroengine according to claim 6, characterized in that, When the ambient temperature where the air flow tube (1) is located is not 20°C, the pneumatic area A of the air flow tube (1) geo，corrected(T) is corrected using the following formula: A geo，corrected(T) = A geo，20℃ *(1 + α 材料 *(T t，MP0 - 293.15)) 2 Among them, A geo，20℃ is the pneumatic area of the air flow tube (1) at an ambient temperature of 20°C, and α 材料 is the expansion coefficient of the material of the air flow tube (1), and T t，MP0 is the total temperature of the measurement section MP0.

8. The calibration method of the inlet air flow tube of an aeroengine according to claim 6, characterized in that Measure the air density ρ of the measurement cross-section MP1 MP1 The calculation is performed using the following formula: Among them, P s，MP1 is the static wall pressure of the air flow tube (1) at the measurement section MP1, R mix is the gas constant, T S，MP1 is the static temperature of the measurement section MP1.

9. The calibration method of the inlet air flow tube of an aeroengine according to claim 8, characterized in that, Measure the static temperature T of the measurement section MP1 S，MP1 The calculation is performed using the following formula: T t，MP1 To measure the total temperature of measurement section MP1, which is equal to the total temperature of measurement section MP0, and is obtained by measuring through the atmospheric parameter measurement point (2). P t，MP1 The total pressure of the measurement section MP1, which is equal to the total pressure of the measurement section MP0, is measured through the atmospheric parameter measurement point (2). P s，MP1 To measure the static pressure of the cross-section MP1, it is measured through the wall static pressure measurement point (3).

10. The calibration method for the inlet air flow tube of an aeroengine according to claim 6, wherein Measure the air velocity c of the measurement cross-section MP1 MP1 The calculation is performed using the following formula: c MP1 = Ma t h ，MP1 * a MP1 Ma th，MP1 To measure the theoretical Mach number of cross-section MP1, the following formula is used for calculation: a MP1 To measure the local sound velocity of cross-section MP1, the following formula is used for calculation: Among them, κ mix is the specific heat ratio, P t，MP1 is the total pressure of the measurement section MP1, P S，MP1 is the static pressure of the measurement section MP1, R mix is the gas constant, T S，MP1 is the static temperature of the measurement section MP1.

Images