A five-hole pressure probe suitable for wide range of turbine stage measurements

Abstract

The present application belongs to the technical field of internal flow pressure test, and particularly relates to a five-hole pressure probe suitable for wide measurement range of turbine interstage. The head support rod is welded with the probe support rod; the probe head is located at the front end of the head support rod, and is provided with mutually independent pressure measuring middle hole, pressure measuring left hole, pressure measuring right hole, pressure measuring upper hole and pressure measuring lower hole; the pressure lead pipe is encapsulated in the probe support rod, one end of which is communicated with the five pressure measuring holes of the probe head, and the other end is led out from the tail of the probe support rod through the pressure lead pipe channel. The present application reduces the interference of the five-hole pressure probe to the measured flow field in the high Mach number range through the innovative structure design of the probe head and the head support rod, so that the high precision measurement in the wide Mach number range can be realized by inserting the probe into the narrow space of the turbine interstage. The present application also proposes two new data processing methods of the five-hole pressure probe, which can effectively expand the angle measurement range of the probe and realize the measurement of wide airflow angle range in the turbine interstage.

Description

Technical Field

[0001] This invention belongs to the field of internal flow pressure testing technology, specifically relating to a five-hole pressure probe suitable for a wide measurement range between turbine stages, applicable to the measurement of three-dimensional flow fields between engine turbine stages. Background Technology

[0002] To obtain the performance parameters of turbine components in an engine and their internal flow field structure, it is necessary to measure the interstage pressure. Currently, the most common measurement method in engineering applications is through contact pressure probes. Five-hole pressure probes are widely used due to their small size, simple structure, and ability to measure the aerodynamic parameters of three-dimensional flow fields.

[0003] However, the small interstage distances and compact spatial structure of the engine turbine components significantly limit the probe's size and place high demands on its structural design. If an attached... Figure 14 The straight probe head structure shown in Figure a (Invention Patent: A High-Speed ​​Train Crosswind Measurement Terminal Based on a Five-Hole Probe, 201711432718.8) cannot measure airflow perpendicular to the probe direction when measuring between turbine stages; if an additional... Figure 14 As shown in Figure b (Invention Patent: A Conical Steady-State Temperature and Pressure Combination Probe for Measuring High Subsonic Three-Dimensional Flow Fields, 201710247025.5), the structure with a hole directly on the side of the probe head will also cause the probe head to stagnate the incoming flow, affecting the accuracy of the probe measurement; Appendix Figure 14 The "L"-shaped head structure shown in Figure c (Invention Patent: A Dynamic Five-Hole Probe, 201710342115.2) can avoid the head's influence on the measurement, but the extended part of the "L" shape is too long to be inserted into the narrow space between turbine stages to complete the measurement. Furthermore, the probe's large size can severely interfere with the measured flow field environment, affecting the measurement accuracy. With continuous optimization of turbine components, the internal airflow velocity is constantly increasing, reaching high subsonic or even supersonic speeds. The measured flow field has a wide Mach number variation range, and the probe's damage to the flow field itself will be more severe. This also brings greater challenges to the probe's aerodynamic design, geometry, and structural design.

[0004] With the pursuit of high performance in modern engines, turbine blades mostly adopt a swept-back design, resulting in significant variations in blade curvature. This means that the airflow angle changes considerably after passing through the first-stage blade, with even greater differences at different blade heights, reaching ±60° or higher. Conventional five-hole probes can only measure angles within a range of approximately ±25°, which is insufficient for measurements in the complex internal flow environment between turbine stages. To address this issue, two common engineering approaches exist: one is to increase the number of holes on the probe, such as seven-hole, twelve-hole, or eighteen-hole probes. However, increasing the number of holes leads to larger probe support diameters and probe sizes, causing more severe interference with the flow field and making it difficult to meet the requirements for high-resolution measurements in confined spaces. Another method is to use a displacement mechanism to hold the five-hole probe, rotating it at different blade heights to measure flow field structures with large airflow angle variations. However, it is difficult to install such a displacement mechanism on smaller, more compact turbine test equipment. Furthermore, using rotation to cover a wide airflow angle measurement range significantly increases testing time and introduces many unnecessary testing errors.

[0005] The aforementioned five-hole pressure probes have limitations in terms of size, structure, and angular measurement range, severely restricting testing tasks and scientific research on engine turbine components. Therefore, there is an urgent need for a five-hole pressure probe suitable for a wide measurement range between turbine stages, used for measuring three-dimensional flow field parameters between engine turbine stages. Summary of the Invention

[0006] To address the limitation of existing five-hole pressure probes in meeting the wide-range measurement requirements between turbine stages, this invention proposes a five-hole pressure probe suitable for such wide measurement ranges. Firstly, through innovative probe head and support structure design, high-precision measurement of the wide Mach number flow field between turbine stages is achieved. Secondly, two new five-hole pressure probe data processing methods are proposed, enabling the measurement of the large airflow angle variation range between turbine stages. This invention presents a novel five-hole pressure probe structure that overcomes the shortcomings of traditional five-hole pressure probe aerodynamic calibration methods, creatively expanding the measurement angle range of the five-hole pressure probe to ±80°, making it applicable to interstage flow field measurements in the Mach number range of 0.1–1.4, thus compensating for the limitations of traditional five-hole pressure probes in this testing environment.

[0007] The technical solution of this invention is:

[0008] 1. A five-hole pressure probe applicable to a wide measurement range of turbine inter-stage width, which is composed of a probe strut (1), a probe head (2), a head strut (3), a pressure measurement central hole (4), a pressure measurement left hole (5), a pressure measurement right hole (6), a pressure measurement upper hole (7), a pressure measurement lower hole (8), a pressure guiding tube channel (9), and a pressure guiding tube (10). It is characterized in that: the head strut (3) is welded to the probe strut (1); the probe head (2) is located at the front end of the head strut (3), and the non-interconnected pressure measurement central hole (4), pressure measurement left hole (5), pressure measurement right hole (6), pressure measurement upper hole (7), and pressure measurement lower hole (8) are opened; the pressure guiding tube (10) is encapsulated inside the probe strut (1), one end is communicated with the five pressure measurement holes of the probe head (2), and the other end is led out from the tail of the probe strut (1) through the pressure guiding tube channel (9);

[0009] 2. Further, the probe strut (1) is a cylinder, and its cross-sectional diameter is 4 mm to 40 mm;

[0010] 3. Further, the head strut (3) is integrally in an "L" shape, with an arc transition at the middle corner. Its cross-sectional shape is a square, with a side length of 0.8 mm to 6 mm. One of the right-angled edges is facing the oncoming flow direction, and the four right-angled edges are polished into rounded corners or remain acute angles. The side surface of the head strut (3) is used as the probe horizontal positioning surface;

[0011] 4. Further, the size of the head strut (3) does not project beyond the cross-section of the probe strut (1) in the top direction, and the distance from the outer edge of the cross-section of the probe strut (1) is 0.5 mm to 1 mm. The distance between the central axis of the probe head (2) and the connection surface of the head strut (3) and the probe strut (1) is 2 to 5 times the side length of the probe strut (1);

[0012] 5. The structure of the probe head (2) is a frustum of a pyramid, with a side cone angle of 3° to 120°, a top surface side length of 0.2 mm to 1.6 mm, and the four side edges are polished into rounded corners or remain acute angles. The pressure measurement central hole (4) is located at the center of the top surface of the frustum of the pyramid, and its central axis is facing the oncoming flow direction. The pressure measurement left hole (5), pressure measurement right hole (6), pressure measurement upper hole (7), and pressure measurement lower hole (8) are respectively located on the four side surfaces of the frustum of the pyramid, and the distance from the pressure measurement central hole (4) is 0.2 mm to 2 mm;

[0013] 6. Further, a wide-range calibration is carried out on a five-hole pressure probe applicable to a wide measurement range of turbine inter-stage width in a calibration wind tunnel. The calibration speed range is 0.1 Mach to 1.4 Mach, the deflection angle range is -80° to 80°, and the pitch angle range is -80° to 80°;

[0014] 7. Furthermore, by employing a wide-range five-hole probe data processing method, calibration curves for the deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient at different deflection and pitch angles are obtained for each Mach number. The wide-range five-hole probe data processing method includes the following two methods:

[0015] The first method is the four-domain method, characterized by:

[0016] Step 1: The yaw angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient are defined as follows:

[0017]

[0018]

[0019]

[0020]

[0021] Where: C py C is the deflection angle coefficient. pp C is the pitch angle coefficient. pt C is the total pressure coefficient. ps The static pressure coefficient is given by Pcalibrated, where Ptotal is the total inflow pressure and static pressure of the calibrated wind tunnel. t and P s The pressure values ​​measured by the middle, left, right, upper, and lower holes of the five-hole pressure probe are P1, P2, P3, P4, and P5, respectively.

[0022] Step 2: Based on the above definitions, obtain the calibration curves for the deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient of each domain at each incoming Mach number. Divide the calibration curves into four domains at the points where the pressure values ​​of the left and right holes are equal, and where the pressure values ​​of the upper and lower holes are equal: the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant.

[0023] Step 3: During actual measurement, first compare the pressure values ​​of the left and right holes and the pressure values ​​of the upper and lower holes to determine the appropriate calibration curve for the corresponding region.

[0024] When the pressure value of the right hole is greater than that of the left hole, and the pressure value of the upper hole is greater than that of the lower hole, the calibration curve in the first quadrant is selected.

[0025] When the pressure value of the left hole is greater than the pressure value of the right hole, and the pressure value of the upper hole is greater than the pressure value of the lower hole, the calibration curve in the second quadrant is selected.

[0026] When the pressure value of the left hole is greater than the pressure value of the right hole, and the pressure value of the lower hole is greater than the pressure value of the upper hole, the calibration curve in the third quadrant is selected.

[0027] When the pressure value of the right hole is greater than that of the left hole, and the pressure value of the lower hole is greater than that of the upper hole, the calibration curve of the fourth quadrant is selected; Step 4: Calculate the deflection angle coefficient and pitch angle coefficient using the actual measured pressure values ​​of the five holes, and then calculate the actual measured deflection angle, pitch angle, total pressure, static pressure and Mach number by interpolation of the calibration curve of the corresponding domain.

[0028] The second method is the Five Domains Method, characterized by:

[0029] Step 1: Based on the data from the five pressure-sensing holes obtained from the wide-range calibration, compare the pressure values ​​of each hole, and divide the calibration data into the middle, left, right, upper, and lower domains according to the location of the hole with the highest pressure value.

[0030] Step 2: The deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient for each domain are defined as follows:

[0031] Middle domain:

[0032] pp=(p1+p2+p3+p4) / 4

[0033]

[0034]

[0035]

[0036]

[0037] Left domain:

[0038] pp=(p4+p5) / 2

[0039]

[0040]

[0041]

[0042]

[0043] Right domain:

[0044] pp=(p4+p5) / 2

[0045]

[0046]

[0047]

[0048]

[0049] Upper domain:

[0050] pp=(p2+p3) / 2

[0051]

[0052]

[0053]

[0054]

[0055] Lower domain:

[0056] pp=(p2+p3) / 2

[0057]

[0058]

[0059]

[0060]

[0061] Where: C py C is the deflection angle coefficient. pp C is the pitch angle coefficient. pt C is the total pressure coefficient. ps The static pressure coefficient is given by Pcalibrated, where Ptotal is the total inflow pressure and static pressure of the calibrated wind tunnel. t and P s The pressure values ​​measured by the middle, left, right, upper, and lower holes of the five-hole pressure probe are P1, P2, P3, P4, and P5, respectively.

[0062] Step 3: Using the above definitions, obtain the calibration curves for the deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient of each domain under different incoming Mach numbers;

[0063] Step 4: During measurement, compare the pressure values ​​of the five holes actually measured. Determine the domain based on the location of the hole with the highest pressure value. Calculate the deflection angle coefficient and pitch angle coefficient according to the definition of the domain. Calculate the actual measured deflection angle, pitch angle, total pressure, static pressure, and Mach number through interpolation of the calibration curve obtained from the calibration.

[0064] The beneficial effects of this invention are:

[0065] Compared with existing five-hole pressure probes, the five-hole pressure probe of the present invention, which is suitable for a wide measurement range between turbine stages, can achieve the following advantages:

[0066] Beneficial effect 1: The probe head support structure in this invention adopts a square rotating design, and the probe head adopts a frustum design. This structure not only facilitates the processing and installation of the probe, but also effectively reduces the interference and blockage effect of the head support on the supersonic airflow, making it suitable for testing flow fields with a wide Mach number range between turbine stages.

[0067] Benefit 2: In this invention, the projection of the five-hole probe head support rod in the top direction does not exceed the cross-section of the probe support rod, which facilitates insertion into the narrow space between turbine stages for testing; the head support rod is shaped like a "T", with a rounded transition at the middle corner. This structural design allows the probe head to be as far away from its head support rod and probe support rod as possible, effectively reducing the impact of the head support rod and probe support rod on measurement accuracy.

[0068] Benefit 3: Compared with the traditional five-hole probe data processing method, the two new five-hole probe data processing methods in this invention have a wider angle measurement range, which makes them better applicable to the testing and research of wide airflow angle variation range between turbine stages. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of the structure of a five-hole pressure probe suitable for a wide measurement range between turbine stages, according to Embodiment 1 of the present invention.

[0070] Figure 2 yes Figure 1 Left view

[0071] Figure 3 yes Figure 2 A magnified view of a portion of the image.

[0072] Figure 4 yes Figure 1 Sectional view of section A.

[0073] Figure 5 yes Figure 1 Section view of section B.

[0074] Figure 6 yes Figure 1 Top view.

[0075] Wherein: 1-Probe support rod, 2-Probe head, 3-Head support rod, 4-Pressure measurement middle hole, 5-Pressure measurement left hole, 6-Pressure measurement right hole, 7-Pressure measurement upper hole, 8-Pressure measurement lower hole, 9-Pressure tapping tube channel, 10-Pressure tapping tube.

[0076] Figure 7 This is an installation diagram of Embodiment 1 of the present invention.

[0077] Wherein: 1-casing, 2-hub, 3-turbine stator, 4-turbine stage rotor under test, 5-turbine stage stator under test, 6-five-hole probe of the present invention for wide-range measurement between turbine stages.

[0078] Figure 8 yes Figure 7 A magnified view of a portion of the image.

[0079] Figure 9 This is a schematic diagram of the calibration curve domain in Embodiment 1 of the present invention.

[0080] Figure 10 This is the first quadrant calibration curve in Embodiment 1 of the present invention.

[0081] Figure 11 This is the second quadrant calibration curve in Embodiment 1 of the present invention.

[0082] Figure 12 This is the third quadrant calibration curve in Embodiment 1 of the present invention.

[0083] Figure 13 This is the fourth quadrant calibration curve in Embodiment 1 of the present invention.

[0084] Figure 14 This is a schematic diagram of the existing technology. Detailed Implementation

[0085] The preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby providing a clearer and more explicit definition of the scope of protection of the present invention.

[0086] Example 1:

[0087] For measuring the three-dimensional flow field between turbine stages, the measurement of the incoming flow angle varies over a large range. To ensure spatial resolution and refined measurement, the following implementation method can be adopted:

[0088] like Figures 1-6 The image shows a five-hole pressure probe of the present invention, suitable for a wide measurement range between turbine stages. Figure 7 and Figure 8 This is a schematic diagram of the probe of the present invention used to measure the three-dimensional flow field between the turbine rotor outlet stages.

[0089] In this embodiment, a five-hole pressure probe applicable to a wide measurement range of turbine inter-stage width is composed of a probe strut (1), a probe head (2), a head strut (3), a pressure measurement central hole (4), a pressure measurement left hole (5), a pressure measurement right hole (6), a pressure measurement upper hole (7), a pressure measurement lower hole (8), a pressure guiding tube channel (9), and a pressure guiding tube (10). It is characterized in that: the head strut (3) is welded to the probe strut (1); the probe head (2) is located at the front end of the head strut (3), and the non-interconnected pressure measurement central hole (4), pressure measurement left hole (5), pressure measurement right hole (6), pressure measurement upper hole (7), and pressure measurement lower hole (8) are opened; the pressure guiding tube (10) is encapsulated inside the probe strut (1), one end is communicated with the five pressure measurement holes of the probe head (2), and the other end is led out from the tail of the probe strut (1) through the pressure guiding tube channel (9);

[0090] Further, the probe strut (1) is a cylinder with a cross-sectional diameter of 6 mm;

[0091] Further, the head strut (3) is integrally in an "L" shape, with an arc transition at the middle corner. Its cross-sectional shape is a square with a side length of 2 mm. One of the right-angled edges faces the oncoming flow direction, and the four right-angled edges are polished into rounded corners. The head strut (3) is used as the probe positioning surface;

[0092] Further, the size of the head strut (3) does not project beyond the cross-section of the probe strut (1) in the top direction, and the distance from the outer edge of the cross-section of the probe strut (1) is 0.5 mm. The distance from the central axis of the probe head (2) to the connection surface of the head strut (3) and the probe strut (1) is 2.5 times the side length of the probe strut (1);

[0093] The structure of the probe head (2) is a frustum of a pyramid, with a side cone angle of 70°, a top surface side length of 1 mm, and the four side edges maintaining acute angles. The pressure measurement central hole (4) is located at the center of the top surface of the frustum of the pyramid, and its central axis faces the oncoming flow direction. The pressure measurement left hole (5), pressure measurement right hole (6), pressure measurement upper hole (7), and pressure measurement lower hole (8) are respectively located on the four side surfaces of the frustum of the pyramid, and the distance from them to the pressure measurement central hole (4) is 1 mm;

[0094] Further, in a calibration wind tunnel, a five-hole pressure probe applicable to a wide measurement range of turbine inter-stage width is calibrated over a wide range. The calibration speed range is 0.1 Mach to 1.4 Mach, the deflection angle range is -70° to 70°, and the pitch angle range is -50° to 50°. The Mach number calibration interval is 0.1 Mach, and the calibration intervals of the deflection angle and pitch angle are both 5°;

[0095] Further, the above calibration data is processed by the four-domain method in the wide-range five-hole probe data processing method. It is characterized in that:

[0096] Step 1: The deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient are defined as follows:

[0097]

[0098]

[0099]

[0100]

[0101] Where: C py C is the deflection angle coefficient. pp C is the pitch angle coefficient. pt C is the total pressure coefficient. ps The static pressure coefficient is given by Pcalibrated, where Ptotal is the total inflow pressure and static pressure of the calibrated wind tunnel. t and P s The pressure values ​​measured by the middle, left, right, upper, and lower holes of the five-hole pressure probe are P1, P2, P3, P4, and P5, respectively.

[0102] Step Two: Using the above definitions, obtain calibration curves for the deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient for each domain under different incoming Mach numbers. Divide the calibration curves into four domains at the points where the pressure values ​​of the left and right orifices are equal, and where the pressure values ​​of the upper and lower orifices are equal: Quadrant I, Quadrant II, Quadrant III, and Quadrant IV. Figure 9 As shown;

[0103] Step 3: During actual measurement, first compare the pressure values ​​of the left and right holes and the pressure values ​​of the upper and lower holes to determine the appropriate calibration curve for the corresponding region.

[0104] When the pressure value of the right hole is greater than that of the left hole, and the pressure value of the upper hole is greater than that of the lower hole, the calibration curve in the first quadrant is selected.

[0105] When the pressure value of the left hole is greater than the pressure value of the right hole, and the pressure value of the upper hole is greater than the pressure value of the lower hole, the calibration curve in the second quadrant is selected.

[0106] When the pressure value of the left hole is greater than the pressure value of the right hole, and the pressure value of the lower hole is greater than the pressure value of the upper hole, the calibration curve in the third quadrant is selected.

[0107] When the pressure value of the right hole is greater than that of the left hole, and the pressure value of the lower hole is greater than that of the upper hole, the calibration curve in the fourth quadrant is selected.

[0108] Calibration curves for each quadrant are as follows Figures 10-13 As shown;

[0109] Step 4: Calculate the deflection angle coefficient and pitch angle coefficient using the actual measured pressure values ​​of the five orifices. Then, calculate the actual measured deflection angle, pitch angle, total pressure, static pressure, and Mach number by interpolating the calibration curve of the corresponding domain.

Claims

1. A method for measuring three-dimensional flow field parameters of an engine based on a five-hole pressure probe with a wide measurement range between turbine stages, wherein the five-hole pressure probe with a wide measurement range consists of a probe support rod (1), a probe head (2), a head support rod (3), a pressure measuring middle hole (4), a pressure measuring left hole (5), a pressure measuring right hole (6), a pressure measuring upper hole (7), a pressure measuring lower hole (8), a pressure tapping tube channel (9), and a pressure tapping tube (10), characterized in that: The described head support rod (3) is welded to the probe support rod (1); the probe head (2) is located at the front end of the head support rod (3), and pressure measurement middle holes (4), pressure measurement left holes (5), pressure measurement right holes (6), pressure measurement upper holes (7), and pressure measurement lower holes (8) that do not communicate with each other are provided; the pressure guiding tube (10) is encapsulated inside the probe support rod (1), one end communicates with the five pressure measurement holes of the probe head (2), and the other end is led out from the tail of the probe support rod (1) through the pressure guiding tube channel (9); Further, the probe support rod (1) is a cylinder, and its cross-sectional diameter is 4 mm to 40 mm; Further, the head support rod (3) is integrally in an "L" shape, with an arc transition at the middle corner, its cross-sectional shape is a square, and the side length is 0.8 mm to 6 mm. One of the right-angled edges is facing the oncoming flow direction, and the four right-angled edges are polished to form rounded corners or kept as acute angles. The head support rod (3) is used as the probe positioning surface; Further, the size of the head support rod (3) does not project beyond the cross-section of the probe support rod (1) in the top direction, and the distance from the outer edge of the cross-section of the probe support rod (1) is 0.5 mm to 1 mm. The distance from the central axis of the probe head (2) to the connection surface of the head support rod (3) and the probe support rod (1) is 2 to 5 times the side length of the probe support rod (1); The structure of the probe head (2) is a frustum of a pyramid, the side cone angle is 30° to 120°, the side length of the top surface is 0.2 mm to 1.6 mm, and the four side edges are polished to form rounded corners or kept as acute angles. The pressure measurement middle hole (4) is located at the center of the top surface of the frustum of the pyramid, and its central axis is facing the oncoming flow direction. The pressure measurement left hole (5), pressure measurement right hole (6), pressure measurement upper hole (7), and pressure measurement lower hole (8) are respectively located on the four side surfaces of the frustum of the pyramid, and the distance from them to the pressure measurement middle hole (4) is 0.2 mm to 2 mm; Further, the wide measurement range five-hole pressure probe is calibrated in a calibration wind tunnel, and the calibration speed range is 0.1 Mach to 1.4 Mach, the deflection angle range is -80° to 80°, and the pitch angle range is -80° to 80°; Further, through the wide range five-hole probe data processing method, calibration curves of the deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient at different deflection angles and pitch angles at each Mach number are obtained. The wide range five-hole probe data processing method is the four-region method, including the following steps: Step 1: The deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient are defined as follows: ； Where: C py C is the deflection angle coefficient. pp C is the pitch angle coefficient. pt C is the total pressure coefficient. ps The static pressure coefficient is given by Pcalibrated, where Ptotal is the total inflow pressure and static pressure of the calibrated wind tunnel. t and P s The pressure values ​​measured by the middle, left, right, upper, and lower holes of the five-hole pressure probe are P1, P2, P3, P4, and P5, respectively. Step 2: Through the above definitions, calibration curves of the deflection angle coefficient, pitch angle coefficient, total pressure coefficient, and static pressure coefficient of each region are obtained at each oncoming flow Mach number. The calibration curves are divided into four regions at the place where the left hole pressure value is equal to the right hole pressure value and the place where the upper hole pressure value is equal to the lower hole pressure value: the first quadrant, the second quadrant, the third quadrant, and the fourth quadrant; Step 3: During actual measurement, first compare the magnitudes of the left and right hole pressure values and the magnitudes of the upper and lower hole pressure values, and judge to select the calibration curve corresponding to the region: When the right hole pressure value is greater than the left hole pressure value and the upper hole pressure value is greater than the lower hole pressure value, select the calibration curve of the first quadrant; When the left hole pressure value is greater than the right hole pressure value and the upper hole pressure value is greater than the lower hole pressure value, select the calibration curve of the second quadrant; When the pressure value of the left hole is greater than the pressure value of the right hole, and the pressure value of the lower hole is greater than the pressure value of the upper hole, the calibration curve in the third quadrant is selected. When the pressure value of the right hole is greater than that of the left hole, and the pressure value of the lower hole is greater than that of the upper hole, the calibration curve in the fourth quadrant is selected. Step 4: Calculate the deflection angle coefficient and pitch angle coefficient using the actual measured pressure values ​​of the five orifices. Then, calculate the actual measured deflection angle, pitch angle, total pressure, static pressure, and Mach number by interpolating the calibration curve of the corresponding domain.

Images