A small perturbation high-resolution dynamic probe for measuring the secondary flow in the stator-rotor end region

Abstract

The present invention belongs to the technical field of subsonic three-dimensional flow field parameter measurement, and particularly relates to a small-disturbance high-resolution dynamic probe for measuring the secondary flow in the rotor-stator end region. It includes a probe head, a strut, a dynamic pressure sensor, and a positioning block. The probe head consists of a cylinder and a double-twist line of revolution body with a common bottom surface. Two dynamic pressure sensors are encapsulated inside it. On the side of the double-twist line of revolution body of the probe head and on the side of the cylinder on the same side, a pressure sensing hole is opened respectively, which is communicated with the dynamic pressure sensors encapsulated inside the probe head. The sensor cables are led out of the probe tail through the inner channel of the probe strut, and a positioning block is sleeved on the probe tail. Through calibration in a calibration wind tunnel, the present invention can measure the dynamic changes of the three-dimensional flow field parameters of the secondary flow in the rotor-stator end region of the turbomachine. The flow field parameters include the pitch angle of the air flow, the yaw angle of the air flow, the total pressure, the static pressure, and the Mach number, providing an actual measurement data basis for improving the performance of the turbomachine. Compared with other double-hole dynamic pressure probes for measuring subsonic three-dimensional flow fields, the present invention has a self-positioning function. The probe head adopts a double-twist line of revolution body structure, the vertical distance between the center of the pressure sensing hole and the lowest point of the probe head is small, and the distance between the center of the inclined hole and the center of the vertical hole is small. It has the advantages of small interference with the end region flow field, high spatial resolution, high frequency response, and can accurately measure the dynamic changes of the pitch angle of the air flow, the yaw angle of the air flow, the total pressure, the static pressure, and the Mach number of the secondary flow in the rotor-stator end region of the turbomachine.

Description

Technical Field

[0001] The present invention belongs to the technical field of subsonic three-dimensional flow field parameter measurement, and particularly relates to a small-disturbance high-resolution dynamic probe for measuring the secondary flow in the tip region between the rotor and the stator, which is applicable to measuring the dynamic changes of the flow field parameters of the secondary flow in the tip region between the rotor and the stator of a turbomachine. The flow field parameters include the pitch angle of the air flow, the yaw angle of the air flow, the total pressure, the static pressure, and the Mach number. Background Technique

[0002] Obtaining the flow field parameters of the secondary flow in the tip region between the rotor and the stator of turbomachines such as fans, compressors, turbines, pumps, blowers, and compressors plays an important role in improving the performance of turbomachines. The tip region between the rotor and the stator of a turbomachine includes the tip region of the blade and the root angle region. For the measurement of the three-dimensional flow field parameters inside the tip region of the blade and the root angle region between the rotor and the stator of a turbomachine, since the flow field includes the wake of the moving blade, the leakage vortex, the corner vortex, and other secondary flows, the flow field has strong unsteadiness and vorticity, and the axial clearance between the rotor and the stator of a turbomachine is very small, especially smaller in medium and small turbomachines. Therefore, for the measurement of the three-dimensional flow field parameters of the secondary flow inside the tip region between the rotor and the stator of a turbomachine, there are measurement difficulties such as a large pitch angle of the air flow, a large yaw angle of the air flow, and a narrow measurement space.

[0003] Conventional steady-state pressure probes can only obtain the steady-state values of flow field parameters and cannot obtain the dynamic changes of flow field parameters; hot-wire probes can measure the dynamic velocity signals of the flow field but cannot provide the dynamic information of the pitch angle of the air flow, the yaw angle of the air flow, the total pressure, the static pressure, and the Mach number. In turbomachine tests, for the measurement of the flow field parameters of the secondary flow in the tip region between the rotor and the stator, we hope to obtain the dynamic changes of the pitch angle of the air flow, the yaw angle of the air flow, the total pressure, the static pressure, and the Mach number of the secondary flow in the tip region between the rotor and the stator for verifying the design of the turbomachine and diagnosing the flow field in order to improve the machine performance, but the above-mentioned probes cannot meet the current test requirements.

[0004] At present, for the measurement of dynamic parameters of subsonic three-dimensional flow fields, single-hole / multi-hole dynamic pressure probes are usually used. When a single-hole dynamic pressure probe measures the dynamic parameters of a three-dimensional flow field, it needs to rotate 7 angles along the axis of the strut, which increases the difficulty of test operation and subsequent data processing. When a multi-hole dynamic pressure probe measures the dynamic parameters of a three-dimensional flow field, it usually rotates 3 angles along the axis of the strut, and the test operation and data processing are relatively simple. At present, three-dimensional multi-hole dynamic pressure probes mainly include two-hole, four-hole, five-hole, and seven-hole dynamic pressure probes. Since the number of pressure sensing holes is the same as the number of dynamic pressure sensors encapsulated inside the probe head, when the number of pressure sensing holes is greater than or equal to 4, the corresponding number of sensors is relatively large. On the one hand, it will increase the manufacturing cost of the probe. On the other hand, limited by the size of the sensors, it is not easy to make the size of the probe head small, resulting in the probe being unable to be inserted into the stator-rotor gap of small and medium-sized turbines for testing. In addition, the large size of the probe head will also reduce the spatial resolution of the probe, lower the measurement accuracy, and seriously interfere with the measured flow field. The two-hole dynamic pressure probe has the potential to measure the dynamic parameters of the three-dimensional flow field in the stator-rotor gap of small and medium-sized turbines due to its small number of sensors and small probe head size. Patent 201710118829.5 introduces a conical two-hole dynamic pressure probe for measuring the transonic three-dimensional flow at the rotor outlet, and its probe head is a cylinder and a cone with a common bottom surface; Patent 201710126245.2 introduces a cylindrical two-hole dynamic pressure probe for measuring the subsonic three-dimensional flow at the rotor outlet, and the probe head is a cylinder and an oblique cut cylinder with a common bottom surface. The connection between the probe heads of these two types of probes is not a smooth surface transition. When the incoming flow angle is large, the air flow is prone to separation near the probe head, seriously interfering with the measured flow field; when the probe is used for measuring the dynamic parameters of the three-dimensional flow field in the end region, the incoming flow will generate a horseshoe vortex when bypassing the cylinder, and the horseshoe vortex will reduce the test accuracy of the probe; in addition, the space at the tip of the cone and the oblique cut cylinder is small, and the dynamic pressure sensor cannot be installed close to the pressure sensing hole, resulting in a large cavity between the pressure sensing hole and the sensor, obvious cavity effect, and low frequency response of the probe; the probe head size is large, and the distance between the centers of the two pressure sensing holes is far, resulting in low spatial resolution of the probe. Therefore, the effects of these two three-dimensional two-hole dynamic pressure probes for measuring the parameters of the secondary flow field in the stator-rotor gap of turbines are not very ideal, and neither of these two probes involves the claim of a positioning block.

[0005] At present, there is little introduction about the probe positioning block. For example, Patent 201710200518.3 introduces a pressure probe positioning block, and a bubble level is sleeved on one side of the base of the positioning block. This positioning block has disadvantages such as large size and single positioning surface. Therefore, in order to measure the dynamic changes of the air flow pitch angle, air flow yaw angle, total pressure, static pressure, and Mach number in the secondary flow field in the stator-rotor gap of turbines, it is urgent to develop a small-disturbance high-resolution dynamic probe with a built-in positioning function. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to measure the dynamic changes of the airflow pitch angle, airflow deflection angle, total pressure, static pressure, and Mach number in the secondary flow field at the rotor-stator end region of subsonic flow. To this end, the present invention provides a small-disturbance high-resolution dynamic probe for measuring the secondary flow at the rotor-stator end region. Compared with other double-hole dynamic pressure probes for measuring the three-dimensional flow field of turbines, the present invention has a self-positioning function. The probe head adopts a double-twist line of revolution structure. The vertical distance from the center of the pressure sensing hole to the lowest point of the probe head is small, and the distance between the center of the inclined hole and the center of the normal hole is small. It has the advantages of small interference with the end region flow field, high spatial resolution, high frequency response, and can accurately measure the dynamic changes of the airflow pitch angle, airflow deflection angle, total pressure, static pressure, and Mach number in the secondary flow at the end region. The present invention is suitable for measuring the dynamic changes of the airflow pitch angle, airflow deflection angle, total pressure, static pressure, and Mach number in the secondary flow field at the rotor-stator end region of turbines.

[0007] The technical solution of the present invention is as follows:

[0008] 1. A small-disturbance high-resolution dynamic probe for measuring the secondary flow at the rotor-stator end region, which is composed of a probe head (1), a strut (2), a dynamic pressure sensor (7), and a positioning block (9). It is characterized in that: the probe head (1) is a cylinder (3) and a double-twist line of revolution (4) with a common bottom surface. The connection between the cylinder (3) and the double-twist line of revolution (4) is a smooth curved surface transition. Two dynamic pressure sensors (7) are encapsulated in the probe head (1); on the side surface of the double-twist line of revolution (4), a pressure sensing hole is opened, which is an inclined hole (5). The inclined hole (5) is connected to a dynamic pressure sensor (7) encapsulated in the probe head (1); on the side surface of the cylinder (3) on the same side as the side surface of the double-twist line of revolution (4) where the inclined hole (5) is located, another pressure sensing hole is opened, which is a normal hole (6). The normal hole (6) is connected to the other encapsulated dynamic pressure sensor (7); the center line of the inclined hole (5), the center line of the normal hole (6), and the axis of the cylinder (3) of the probe head (1) are in the same plane; the axis of the cylinder (3) of the probe head (1) coincides with the axis of the probe strut (2).

[0009] 2. Further, the diameter of the cylinder (3) of the probe head (1) is d, and the value range is 2.5 mm ≤ d ≤ 3.6 mm, and the length is 4d to 8d.

[0010] 3. Further, the solid of revolution (4) is formed by rotating the AB curve segment on the lemniscate around the axis L. Point A is the intersection point of the lemniscate, the tangent line at point B is perpendicular to the tangent line at point A, and the rotation axis L passes through point A and is perpendicular to the tangent line at point A.

[0011] 4. Further, the diameter of the inclined hole (5) is 0.2 mm to 0.4 mm, and the included angle between the center line of the inclined hole (5) and the axis of the cylinder (3) of the probe head (1) is θ, and the value range is 0° ≤ θ < 90°.

[0012] 5. Further, the vertical distance between the center of the inclined hole (5) and the lowest point on the surface of the tore - shaped body of revolution (4) is h1, and its value range is 0d ≤ h < 0.29d.

[0013] 6. Further, the diameter of the positive hole (6) is from 0.2 mm to 0.4 mm, and the vertical distance between the center of the positive hole (5) and the lowest point on the surface of the body of revolution (4) is h2, and its value range is 0.29d ≤ h2 ≤ 0.6d.

[0014] 7. Further, the probe support rod (2) is a cylinder with a diameter of D, and its value range is 4 mm ≤ D ≤ 10 mm. There is a circular pipe inside it. The cable (8) of the dynamic pressure sensor encapsulated in the probe head (1) is led out of the probe tail through the pipe inside the probe support rod (2). A positioning block (9) is sleeved on the probe tail.

[0015] 8. Further, the positioning block (9) is an integral structure, including a cuboid base (10), a cylindrical boss (11), a through - hole (12), and a threaded hole (13). It is sleeved on the probe tail through the through - hole (12) and fixed by a countersunk head screw (14) passing through the threaded holes (13) on both sides of the boss (11). The countersunk head screw (14) is fully embedded in the threaded hole (13).

[0016] 9. Further, the cuboid base (10) includes four rectangular sides and two square bottoms. Among the four sides, two adjacent sides are perpendicular to each other, and all four sides can be used as positioning surfaces. One bottom surface of the base (10) is connected to the cylindrical boss (11), and the perpendicular bisector of the bottom surface coincides with the axis of the boss (11). The axis of the boss (11) coincides with the center line of the through - hole (12). The diameter of the through - hole is D + 0.05 mm, the outer diameter of the boss (11) is M, and its value range is D + 2 mm ≤ M ≤ D + 5 mm. The side length of the bottom surface of the base (10) is from M to M + 3 mm, and the thickness of the base (10) is H, and its value range is 2 mm ≤ H ≤ 5 mm.

[0017] The beneficial effects of the present invention are as follows:

[0018] Compared with the current double - hole dynamic pressure probes used for other purposes, the present invention is a small - perturbation high - resolution dynamic probe for measuring the secondary flow in the rotor - stator end region, and has the following beneficial effects:

[0019] Beneficial effect one: The probe head of the present invention adopts a tore - shaped body of revolution structure. The vertical distances between the centers of the two pressure - sensing holes and the lowest point on the surface of the tore - shaped body of revolution are small. The present invention can measure the dynamic parameters of the secondary flow field in the end region closer to the wall surface.

[0020] Beneficial effect two: The smooth surface transition between the double-twist line of revolution body and the cylindrical surface of the probe head. When the air flow passes through the surface of the double-twist line of revolution body, the special structure of the double-twist line of revolution body can suppress the air flow separation on its surface, weaken the interference of the flow around the strut head on the flow field in the measured area. On the other hand, when measuring the flow field parameters near the end wall, the present invention can suppress the scale of the horseshoe vortex at the front end of the probe head and reduce the measurement error.

[0021] Beneficial effect three: The body of revolution is flat. This structure, on the one hand, makes the distance between the center of the inclined hole and the center of the positive hole closer, improving the spatial resolution of the probe. On the other hand, it enables the dynamic pressure sensor connected to the inclined hole to be installed closer to the inclined hole, greatly reducing the cavity volume between the inclined hole and the sensor, reducing the cavity effect, and improving the frequency response of the probe.

[0022] Beneficial effect four: The size of the probe head of the present invention is relatively small. The present invention can be inserted into the measurement end area of the stator-rotor interface of the turbomachine to measure the dynamic changes of the secondary flow field parameters and cause less interference to the measured flow field.

[0023] Beneficial effect five: The positioning block adopted by the present invention is small in size and has little influence on the probe during the measurement process. Since all four side surfaces of the positioning block can be used as positioning surfaces and can be replaced with each other, the positioning process is simple and convenient, making it more suitable for practical engineering applications. Brief description of the drawings

[0024] Figure 1 is the structural schematic diagram of the present invention.

[0025] Figure 2 is the generation process of the double-twist line of revolution body.

[0026] Figure 3 is Figure 1 the right side view of

[0027] Figure 4 is Figure 3 the partial enlarged view of

[0028] Figure 5 is Figure 3 the top view of

[0029] Figure 6 is the test layout diagram of the probe.

[0030] Wherein: 1 - probe head, 2 - probe strut, 3 - cylinder, 4 - double-twist line of revolution body, 5 - inclined hole, 6 - positive hole, 7 - dynamic pressure sensor, 8 - cable of the dynamic pressure sensor, 9 - positioning block, 10 - cuboid base, 11 - cylindrical boss, 12 - through hole, 13 - threaded hole, 14 - countersunk head screw, 15 - casing, 16 - rotor, 17 - stator, 18 - hub. Detailed implementation mode

[0031] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0032] As Figure 1 shown, in this embodiment, a small-disturbance high-resolution dynamic probe for measuring the secondary flow in the stator-rotor end region is introduced, which is composed of a probe head (1), a strut (2), a dynamic pressure sensor (7), and a positioning block (9). Its characteristics are as follows: the probe head (1) is a cylinder (3) and a surface of revolution formed by a lemniscate, with a smooth curved surface transition at the connection between the cylinder (3) and the surface of revolution formed by the lemniscate. Two dynamic pressure sensors (7) are encapsulated in the probe head (1); on the side surface of the surface of revolution formed by the lemniscate, a pressure sensing hole, namely an inclined hole (5), is opened, and the inclined hole (5) is communicated with one of the dynamic pressure sensors (7) encapsulated in the probe head (1); on the side surface of the cylinder (3) on the same side as the side surface of the surface of revolution formed by the lemniscate where the inclined hole (5) is located, another pressure sensing hole, namely a normal hole (6), is opened, and the normal hole (6) is communicated with the other encapsulated dynamic pressure sensor (7); the center lines of the inclined hole (5) and the normal hole (6) and the axis of the cylinder (3) of the probe head (1) are in the same plane; the axis of the cylinder (3) of the probe head (1) coincides with the axis of the probe strut (2).

[0033] The diameter of the cylinder (3) of the probe head (1) is 3.5 mm and the length is 15 mm.

[0034] The surface of revolution (4) is formed by rotating the AB curve segment on the lemniscate around the axis L. Point A is the intersection point of the lemniscate, the tangent line at point B is perpendicular to the tangent line at point A, and the rotation axis L passes through point A and is perpendicular to the tangent line at point A.

[0035] The diameter of the inclined hole (5) is 0.3 mm, and the included angle between the center line of the inclined hole (5) and the axis of the cylinder (3) of the probe head (1) is 73°.

[0036] The vertical distance from the center of the inclined hole (5) to the lowest point on the surface of the surface of revolution formed by the lemniscate is 0.2 mm.

[0037] The diameter of the normal hole (6) is 0.3 mm, and the vertical distance from the center of the normal hole (6) to the lowest point on the surface of the surface of revolution (4) is 1 mm.

[0038] The probe strut (2) is a cylinder with a diameter of 6 mm. A circular pipe is opened inside it, and the cable (8) of the dynamic pressure sensor encapsulated in the probe head (1) is led out of the probe tail through the pipe inside the probe strut (2), and a positioning block (9) is sleeved on the probe tail.

[0039] The positioning block (9) is an integral structure, including a cuboid base (10), a cylindrical boss (11), a through hole (12), and a threaded hole (13). It is sleeved on the tail of the probe through the through hole (12) and fixed by countersunk head screws (14) passing through the threaded holes (13) on both sides of the boss (10). The countersunk head screws (14) are completely embedded in the threaded holes (13).

[0040] The cuboid base (10) includes four rectangular sides and two square bottoms. Two adjacent sides among the four sides are perpendicular to each other, and all four sides can be used as positioning surfaces. One bottom surface of the base (10) is connected to the cylindrical boss (11), and the perpendicular bisector of the bottom surface coincides with the axis of the boss (11). The axis of the boss (11) coincides with the center line of the through hole (12). The diameter of the through hole is 6.05 mm, the outer diameter of the boss is 9 mm, the side length of the bottom surface of the base (10) is 11 mm, and the thickness of the base (10) is 3 mm.

[0041] Calibrate the probe in a subsonic calibration wind tunnel. Select one side of the base (10) of the positioning block (9) as the positioning surface. Determine the relative position between the positioning surface of the positioning block (9) and the positive hole (6) through a level. Fix the positioning block (9) with countersunk head screws (14). Obtain the pneumatic calibration coefficients of the probe at different incoming flow directions and different Mach numbers.

[0042] In actual measurement, install and fix the probe on the displacement mechanism. The specific process is as follows: Use a level to adjust the positioning surface of the displacement mechanism to be horizontal. Install the probe on the displacement mechanism. Place a level on the positioning surface of the positioning block (9) of the probe. Rotate the probe along the axis of the probe strut (2). Adjust the positioning surface to be horizontal through the level. Determine the relative position between the center line of the positive hole (6) and the positioning surface of the displacement mechanism. Fix the probe on the displacement mechanism. The displacement mechanism for installing the probe is installed on the measured turbomachinery casing (15) through a positioning device. Adjust the displacement mechanism to insert the probe into a certain radial position in the end region flow field. As Figure 6 shown, according to the known average incoming flow direction, adjust the probe through the displacement mechanism so that the positive hole (6) is aligned with the average incoming flow direction. Taking this position as the reference, use the displacement mechanism to drive the probe to rotate 1 angle counterclockwise and clockwise around the axis of the probe strut (2). The rotation angle is 40°. A total of 3 angular positions are measured. At each angular position, combined with the pneumatic calibration coefficients of the probe at different incoming flow directions and different Mach numbers obtained in the subsonic calibration wind tunnel, calculate the pitch angle, yaw angle, total pressure, static pressure, and Mach number of the airflow in the measured flow field.

[0043] The present invention has a built-in positioning function. The positioning block (9) adopted has a small size and has little influence on the probe during the measurement process. Since all four side surfaces can be used as positioning surfaces and can be replaced with each other, the positioning process is simple and convenient, making it more suitable for practical engineering applications. In the present invention, the vertical distances from the center of the inclined hole (5) of the pressure sensing hole and the center of the normal hole (6) to the lowest point on the surface of the convolute of the double-twist line (4) are relatively small, and the dynamic parameters of the secondary flow field in the end region closer to the wall surface between the turbine rotor (16) and the stator (17) can be measured; the convolute of the double-twist line (4) on the probe head (1) can suppress the separation of the air flow when it flows over its surface and weaken the interference of the flow around the strut head on the measured flow field. When measuring the flow field parameters in the near-wall end region, the convolute of the double-twist line (4) can also suppress the scale of the horseshoe vortex at the front end of the probe head (1). Therefore, this structure can reduce the measurement error of the secondary flow field in the end region; the convolute (4) is flat. On the one hand, the distance between the center of the inclined hole (5) and the center of the normal hole (6) can be made closer, improving the spatial resolution of the probe. On the other hand, the dynamic pressure sensor (7) communicated with the inclined hole (5) can be installed closer to the inclined hole (5), which can greatly reduce the cavity volume between the inclined hole (5) and the sensor, reduce the cavity effect, and improve the frequency response of the probe. The probe head (1) of the present invention has a relatively small size and little interference on the measured flow field, and can be inserted between the turbine rotor (16) and the stator (17) to measure the dynamic changes of the pitch angle, yaw angle, total pressure, static pressure and Mach number of the secondary flow in the end region.

Claims

1. A method of using a small-perturbation high-resolution dynamic probe for measuring the secondary flow in the tip region between a rotor and a stator to achieve the dynamic measurement of the flow field parameters of the secondary flow in the tip region between a turbine rotor and a stator. The flow field parameters include the pitch angle of the air flow, the deflection angle of the air flow, the total pressure, the static pressure, and the Mach number. The structure of the small-perturbation high-resolution dynamic probe for measuring the secondary flow in the tip region between a rotor and a stator consists of a probe head (1), a strut (2), a dynamic pressure sensor (7), and a positioning block (9), and is characterized in that: The probe head (1) is composed of a cylinder (3) and a spirograph body (4) with a common bottom surface. The connection between the cylinder (3) and the spirograph body (4) is a smooth curved surface transition. Two dynamic pressure sensors (7) are encapsulated inside the probe head (1). On the side surface of the spirograph body (4), an inclined hole (5) is opened as a pressure sensing hole, and the inclined hole (5) is communicated with one of the dynamic pressure sensors (7) encapsulated inside the probe head (1). On the side surface of the cylinder (3) on the same side as the side surface of the spirograph body (4) where the inclined hole (5) is located, another pressure sensing hole is opened, which is a straight hole (6), and the straight hole (6) is communicated with the other encapsulated dynamic pressure sensor (7). The center line of the inclined hole (5), the center line of the straight hole (6), and the axis of the cylinder (3) of the probe head (1) are in the same plane. The axis of the cylinder (3) of the probe head (1) coincides with the axis of the probe rod (2). The diameter of the cylinder (3) of the probe head (1) is d, and the value range is 2.5 mm ≤ d ≤ 3.6 mm, and the length is 4d to 8d. The spirograph body (4) is formed by rotating the AB curve segment on the lemniscate around the axis L. Point A is the intersection point of the lemniscate, the tangent line at point B is perpendicular to the tangent line at point A, and the rotation axis L passes through point A and is perpendicular to the tangent line at point A. The diameter of the inclined hole (5) is 0.2 mm to 0.4 mm, and the included angle between the center line of the inclined hole (5) and the axis of the cylinder (3) of the probe head (1) is θ, and the value range is 0° ≤ θ < 90°. The vertical distance from the center of the inclined hole (5) to the lowest point on the surface of the spirograph body (4) is h1, and the value range is 0d ≤ h1 < 0.29d. The diameter of the straight hole (6) is 0.2 mm to 0.4 mm, and the vertical distance from the center of the straight hole (5) to the lowest point on the surface of the spirograph body (4) is h2, and the value range is 0.29d ≤ h2 ≤ 0.6d. The probe rod (2) is a cylinder with a diameter of D, and the value range is 6 mm ≤ D ≤ 10 mm. A circular pipe is opened inside it. The cable (8) of the dynamic pressure sensor encapsulated inside the probe head (1) is led out of the probe tail through the pipe inside the probe rod (2), and a positioning block (8) is sleeved on the probe tail. The positioning block (9) is an integral structure, including a cuboid base (10), a cylindrical boss (11), a through hole (12), and a threaded hole (13). It is sleeved on the probe tail through the through hole (12) and fixed by a countersunk head screw (14) passing through the threaded holes (13) on both sides of the boss (11), and the countersunk head screw (14) is completely embedded in the threaded hole (13). The cuboid base (10) includes four rectangular side faces and two square bottom faces. Two adjacent side faces among the four side faces are perpendicular to each other, and all four side faces can be used as positioning faces. One bottom face of the base (10) is connected to the cylindrical boss (11), and the perpendicular bisector of the bottom face coincides with the axis of the boss (11). The axis of the boss (11) coincides with the center line of the through hole (12). The diameter of the through hole is D + 0.05 mm, the outer diameter of the boss (11) is M, and the value range is D + 2 mm ≤ M ≤ D + 5 mm. The side length of the bottom face of the base (10) is M to M + 3 mm, and the thickness of the base (10) is H, and the value range is 2 mm ≤ H ≤ 5 mm; Calibrate the probe in a subsonic calibration wind tunnel. Select one side face of the base (10) of the positioning block (9) as the positioning face. Determine the relative position between the positioning face of the positioning block (9) and the positive hole (6) by a spirit level. Fix the positioning block (9) with countersunk head screws (14). Obtain the pneumatic calibration coefficients of the probe at different oncoming flow directions and different Mach numbers; The usage steps are as follows: In the first step, use a spirit level to adjust the level of the positioning face of the displacement mechanism. Install the probe on the displacement mechanism. Place a spirit level on the positioning face of the probe positioning block (9). Rotate the probe along the axis of the probe strut (2). Adjust the level of the positioning face by the spirit level to determine the relative position between the center line of the positive hole (6) and the positioning face of the displacement mechanism. Fix the probe on the displacement mechanism; In the second step: Install the displacement mechanism of the probe on the measured turbine casing (15) through the positioning device. Adjust the displacement mechanism to insert the probe into a certain radial position in the end region flow field. According to the known average oncoming flow direction, adjust the probe through the displacement mechanism to align the positive hole (6) with the average oncoming flow direction; In the third step: Taking this position as the reference, use the displacement mechanism to drive the probe to rotate 1 angle in the counterclockwise and clockwise directions around the axis of the probe strut (2). The rotation angle is 30° to 45°, and a total of 3 angular positions are measured; In the fourth step: At each angular position, combine the pneumatic calibration coefficients of the probe obtained in the subsonic calibration wind tunnel at different oncoming flow directions and different Mach numbers to calculate the pitch angle, yaw angle, total pressure, static pressure and Mach number of the air flow in the measured flow field.

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