A device for measuring the dynamic total pressure of intake distorted flow field

Abstract

The present invention belongs to the technical field of dynamic total pressure parameter testing, and specifically relates to a device for measuring the dynamic total pressure of an intake distorted flow field. The intake distorted flow field has a large area. If the dynamic total pressure thereof is to be measured, a multi-point dynamic total pressure probe comb is generally used. The traditional measurement method has the following problems: (1) There are many probe combs, which cause large blockage of the flow field; (2) The probe comb probe structure has a small insensitive angle to the airflow direction and a low frequency response; (3) The utilization efficiency is low and the cost is high. In order to solve these problems, the present invention is composed of a probe comb support rod, a single-hole dynamic total pressure probe, a mounting seat, and a rotating mechanism, which can reduce the number of pressure sensors and the number of probe combs, reduce the interference of the probe comb support rod on the measured flow field, simplify the test operation, reduce the test cost, and at the same time increase the probe measurement insensitive angle, improve the measurement frequency response, and realize 360° all-round measurement of a certain plane of the measured flow field, thereby improving the test accuracy.

Description

Technical Field

[0001] The invention belongs to the technical field of dynamic total pressure parameter testing, and in particular relates to a device for measuring the dynamic total pressure of an intake distorted flow field. Background Art

[0002] Total pressure distortion is a phenomenon in which the total pressure is unevenly distributed circumferentially or radially, which will cause the engine's performance loss and stability problems. Severe total pressure distortion will cause the fan / compressor to stall or surge, the engine to enter an unstable working state, and even cause the engine to stop in the air, causing a serious accident of the aircraft; at the same time, total pressure distortion will also cause engine structural damage and failure; total pressure distortion will induce synchronous vibration response of fan / compressor blades and impellers, resulting in uneven combustion temperature field in the combustion chamber, resulting in problems such as excessive thermal stress on turbine blades leading to premature damage;

[0003] Initially, only steady-state total pressure distortion was considered in the pressure distortion research. Later, it was gradually found that only steady-state total pressure distortion was insufficient. Dynamic total pressure distortion had different effects from steady-state total pressure distortion. Due to the existence of pressure fluctuation, the engine inlet flow rate would fluctuate, resulting in performance loss. On the other hand, due to the existence of pressure fluctuation, the actual dynamic peak total pressure distortion value would be greater than the steady-state total pressure distortion value, thus affecting stability.

[0004] The intake distortion flow field area is large. If the dynamic total pressure is to be measured, a multi-point dynamic total pressure probe comb is generally used. It is usually required to arrange 6 probe combs in a "water" shape or 8 probe combs in a "rice" shape at equal angles in the circumferential direction. The traditional measurement method has the following problems: (1) The large number of probe combs causes large blockage of the flow field; (2) The probe comb structure is insensitive to the airflow direction at a small angle and has a low frequency response, resulting in large measurement errors; (3) The sensor adopts an inlaid connection method and cannot be removed after installation. If a sensor is damaged, the entire probe comb will be scrapped, resulting in low utilization efficiency. Summary of the invention

[0005] The technical problem to be solved by the present invention is to obtain the dynamic total pressure parameters of the intake distorted flow field; to this end, the present invention specifically relates to a device for measuring the dynamic total pressure of the intake distorted flow field to solve the shortcomings of traditional testing methods.

[0006] The design scheme of the present invention is:

[0007] 1. A device for measuring the dynamic total pressure of an intake distorted flow field comprises a probe comb support rod (1), a single-hole dynamic total pressure probe (2), a mounting seat (3), and a rotating mechanism (4); a pressure sensor (8) is fixed to the single-hole dynamic total pressure probe (2) by means of glue; the single-hole dynamic total pressure probe (2) is mounted on the probe comb support rod (1) by means of a thread (7); and the probe comb is mounted on the rotating mechanism (4) by means of a mounting seat (3);

[0008] 2. Furthermore, the single-hole dynamic total pressure probe (2) is spherical (9), and its cross-sectional profile is 1 / 4 of the circumference; a small circular hole (5) is opened on the probe, and it can be disassembled and assembled with a special fixture; the tail of the probe is designed with a back-cut groove (6) and a thread (7) behind the back-cut groove. ;

[0009] 3. Furthermore, a groove (12) is opened at the rear of the probe comb support rod (1) to facilitate the arrangement of the pressure sensor cable; a threaded hole (13) is opened at the front to facilitate the installation of a single-hole dynamic total pressure probe (2); the probe arrangement can be arranged according to an equal annular surface, or according to the Chebyshev integration method and the logarithmic linear method; after the single-hole dynamic total pressure probe (2) is installed, filling materials are filled and the groove (12) opened at the rear is sealed to fix the pressure sensor cable and ensure that the airflow does not enter from the groove opened at the rear of the probe comb support rod to avoid affecting the measurement, while enhancing the strength of the probe comb support rod.

[0010] 4. Further, the probe comb is fixed to the rotating mechanism (4) through the designed four circular holes (10) and bolts; a straight section (11) is designed at the front of the mounting seat for positioning;

[0011] 5. Furthermore, the rotating mechanism (4) is mainly composed of a gear transmission mechanism (14) and a motor (15), so as to realize 360° rotation of the probe comb around the axis direction;

[0012] The present invention can reduce the number of pressure sensors and the number of probe combs, weaken the interference of the probe comb support rods on the measured flow field, simplify the test operation, reduce the test cost, and at the same time increase the probe measurement insensitive angle, improve the measurement frequency response, realize 360° all-round measurement of a certain plane of the measured flow field, and improve the test accuracy.

[0013] Compared with the traditional testing scheme, the beneficial effects of the present invention are:

[0014] Beneficial effect 1: The insensitive angle of the total pressure probe is improved; the single-hole total pressure probe on the traditional probe comb adopts a 45° inner chamfer. The inventors compared various probe structures through numerical simulation and experiments and found that the ball-and-socket probe has a larger insensitive angle, which can reach 50°, thereby improving the measurement accuracy;

[0015] Beneficial effect 2: The frequency response of the total pressure probe is improved; the single-hole total pressure probe on the traditional probe comb generally adopts a pressure lead pipe, or the pressure sensor is installed at the rear of the single-hole total pressure probe. This installation method leads to obvious cavity effect and low measurement frequency response; the present invention directly installs the pressure sensor on the single-hole total pressure probe, the cavity between the sensor and the pressure sensing hole is small, the cavity effect is not obvious, and the frequency response of the probe is high, which can reach 100kHz;

[0016] Beneficial effect three: the number of measurement points is increased; the traditional test scheme is to arrange 6 probe combs at equal angles in the shape of a "water" or 8 probe combs at equal angles in the shape of a "rice" on the cross section to be measured. The method of the present invention cannot be used to rotate the probe comb using a rotating mechanism to achieve multi-point measurement. The reason is that the total pressure probe of the traditional probe comb is steady-state and is measured through a pressure pipe, or the pressure sensor is arranged at the rear of the probe, and its measurement frequency response is low, while the distorted flow field is dynamic. If it is rotated, the traditional probe comb cannot meet its measurement frequency response requirements, and the measurement result accuracy is very low; the present invention uses a rotating mechanism to achieve 360° dynamic measurement, and the number of measurement points is several times or even dozens of times that of the traditional scheme, thereby improving the measurement accuracy;

[0017] Beneficial effect four: high utilization rate and reduced testing cost; the traditional probe comb adopts an integrated design as a whole, that is, the probe is often embedded in the probe comb support rod. If one probe is damaged, the entire probe comb will be scrapped; the present invention adopts a refined design, focusing on reuse and detachability, especially the probe design, which is designed with small round holes and threads for disassembly. If one probe is damaged, only a single probe needs to be reprocessed for replacement. The processing cost of a single probe is much lower than that of the entire probe comb, the overall utilization rate is high, and the testing cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a device for measuring the dynamic total pressure of the intake distorted flow field.

[0019] Figure 2 yes Figure 1 Front view of .

[0020] Figure 3 It is a schematic diagram of a single-hole dynamic pressure probe.

[0021] Figure 4 yes Figure 3 sectional view of .

[0022] Figure 5 yes Figure 3 Schematic diagram of the probe comb support rods.

[0023] Figure 6 yes Figure 5 Rear view of.

[0024] Wherein: 1-probe comb support rod, 2-single hole dynamic total pressure probe, 3-mounting seat, 4-rotating mechanism, 5-small round hole on the probe, 6-knife withdrawal groove, 7-probe rear thread, 8-pressure sensor, 9-ball socket, 10-round hole on the mounting seat, 11-straight section on the mounting seat, 12-slot opened at the rear of the probe comb support rod, 13-threaded hole, 14-gear transmission mechanism, 15-motor. DETAILED DESCRIPTION

[0025] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0026] like Figure 3 , Figure 4 As shown, the outer diameter of the single-hole total pressure probe (2) is 5 mm and the inner diameter is 1.8 mm; the small circular hole (5) opened in the middle of the single-hole total pressure probe (2) has a diameter of 1 mm and a depth of 1 mm. The probe is thickened at the opening and has an outer diameter of 6 mm; the front part of the single-hole total pressure probe (2), i.e., the part in front of the undercut groove (6), is 10 mm long; the undercut groove is 1 mm wide and 0.5 mm deep; the thread (7) at the rear of the single-hole total pressure probe (2) is a standard thread of M5×0.5 and 7 mm long; the chamfering method of the head of the single-hole total pressure probe (2) is a ball socket shape (9), from Figure 4 From an angle, it is a 1 / 4 arc line with a radius of 1.6 mm; a pressure sensor (8) is installed inside the single-hole total pressure probe (2);

[0027] like Figure 5 , Figure 6 As shown, 6 M5×0.5 threaded holes (13) with a depth of 7 mm are opened on the probe comb support rod (1), and the opening positions are arranged along the radial equal annular surface. The distances between the center of each threaded hole and the center of the bottom of the mounting seat are 19.5 mm, 60.5 mm, 106.5 mm, 160.5 mm, 226.5 mm, and 321.5 mm respectively; the probe comb support rod (1) is a waist-shaped rod with a radial length of 330 mm and a thickness designed to be equal in strength along the radial direction. A groove (12) is opened on the back, and the groove (12) is 5 mm wide and 310 mm long; the mounting seat (3) has a cross-sectional diameter of 100 mm and a thickness of 6 mm. The circular holes on the four mounting seats are distributed at equal angles, with a diameter of 10 mm and passing through the mounting seat. The center of the circular hole (10) is 80 mm away from the center of the mounting seat (3); the length of the straight section on the mounting seat (3) is 30 mm;

[0028] like Figure 1 , Figure 2 As shown, the rotating mechanism (4) is mainly composed of a motor (14) and a gear transmission mechanism (13). The single-hole total pressure probe (2) is installed on the probe comb support rod (1), and then the whole is installed on the rotating mechanism (4) to measure the dynamic total pressure of the intake distortion flow field of the aircraft engine;

[0029] The present invention can be installed on the inner wall surface of the transition section of the air inlet of an aircraft engine. The probe comb is firmly installed and has reliable structural strength, and can realize the measurement of the dynamic total pressure of the intake distortion flow field.

Claims

1. A device for measuring the dynamic total pressure of an intake distorted flow field, characterized in that: It is composed of a probe comb support rod (1), a single-hole dynamic total pressure probe (2), a mounting seat (3), and a rotating mechanism (4); the pressure sensor (8) is fixed to the single-hole dynamic total pressure probe (2) by means of glue; the single-hole dynamic total pressure probe (2) is mounted on the probe comb support rod (1) by means of a thread (7); and the probe is mounted on the rotating mechanism (4) by means of the mounting seat (3); The head of the single-hole dynamic total pressure probe (2) is chamfered in a ball-socket shape (9), and its cross-sectional profile is 1 / 4 of a circle: a small circular hole (5) is opened on the probe, and it can be disassembled and assembled using a special fixture; the tail of the probe is designed with a cutter groove (6) and a thread (7) behind the cutter groove; The probe comb support rod (1) has a groove (12) at the rear to arrange the pressure sensor cable; a plurality of threaded holes (13) are opened at the front to install the single-hole dynamic total pressure probe (2): the probe arrangement can be arranged according to the equal annular surface, Chebyshev integration method or logarithmic linear method. After the single-hole dynamic total pressure probe (2) is installed, fill the material and seal the groove (12) at the rear to fix the pressure sensor cable and ensure that the airflow does not enter from the groove at the rear of the probe comb support rod to avoid affecting the measurement, while enhancing the strength of the probe comb support rod; Four circular holes (10) are designed, the circular holes are distributed at equal angles, and the center distance is 60-80 cm according to the mounting seat; The probe is fixed to the rotating mechanism (4) by means of bolts; The front part of the mounting seat is designed with a straight section (11) for easy positioning; The rotating mechanism (4) is mainly composed of a gear transmission mechanism (14) and a motor (15), and realizes 360° rotation of the probe around the axis direction; The device can reduce the number of pressure sensors and probe combs, weaken the interference of the probe comb support rod on the measured flow field, simplify the test operation, reduce the test cost, and at the same time increase the probe measurement insensitive angle, which can reach 50°, improve the measurement frequency response, which can reach 100kHz, realize 360° all-round measurement of a certain plane of the measured flow field, and improve the test accuracy.

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