A grate leakage test device and method suitable for low Reynolds number flow

Abstract

The present invention relates to the field of aero-engine technology, and discloses a grate leakage test device and method suitable for low Reynolds number flow. The test device includes an intake section, a grate stator ring, a grate rotor disk, an exhaust section, and a flowmeter. A tubular rectifier is coaxially arranged in the exhaust section, and the tubular rectifier is mainly composed of a plurality of rectifier circular tubes adjacent to each other. The present invention uses a tubular rectifier to be arranged in the exhaust section, and uses the tubular rectifier to first rectify the airflow of the test grate leakage, and then performs flow measurement. It can suppress the measurement error caused by the airflow rotation and uneven airflow distribution under low Reynolds number conditions, thereby improving the measurement accuracy of the leakage airflow under low Reynolds number conditions, facilitating the effective implementation of the grate flow characteristic test under low Reynolds number conditions, so as to support the grate sealing design and accurate analysis of the leakage under low Reynolds number conditions, and avoid the problem of large errors in the existing grate leakage analysis method under low Reynolds number conditions.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engines and discloses a grate tooth leakage test device and method suitable for low Reynolds number flow. Background Art

[0002] Comb teeth are an effective, long-life non-contact sealing structure that is widely used in engines and other rotating machinery. This type of sealing structure is the most important throttling element in the internal air flow system of an aircraft engine. Its main functions are to reduce the leakage of cooling air from high-pressure areas to low-pressure areas and adjust chamber pressure to ensure the normal operation of the aircraft engine within the entire flight envelope.

[0003] With the widening of the operating envelope of aircraft engines, the influence of the low Reynolds number effect on the flow field needs to be considered under operating conditions of extremely low intake pressure and intake flow. For the grate seal structure, the low Reynolds number flow inside it will cause significant changes in the sealing performance. The existing grate leakage test system does not have the testing capability under low Reynolds number conditions, resulting in the inability to accurately evaluate the performance of the grate seal structure under extreme working environments. Summary of the Invention

[0004] The purpose of the present invention is to provide a grate leakage test device and method suitable for low Reynolds number flow, which can suppress the measurement errors caused by airflow rotation and uneven airflow distribution under low Reynolds number conditions, thereby improving the measurement accuracy of leakage airflow under low Reynolds number conditions.

[0005] In order to achieve the above technical effects, the technical solution adopted by the present invention is:

[0006] A grate leakage test device suitable for low Reynolds number flow, comprising:

[0007] An air intake section, comprising an air intake outer casing and an air intake inner casing arranged coaxially;

[0008] A grate stator ring, wherein the grate stator ring is coaxially fixedly connected to the outlet end of the air inlet outer casing;

[0009] A grate rotor disc, the grate rotor disc and the grate stator ring are coaxially arranged, and the grate rotor disc is located inside the grate stator ring. The grate rotor disc is further provided with test grate teeth that are clearance-matched with the grate stator ring. The grate rotor disc is movably and sealedly connected to the intake inner casing;

[0010] An exhaust section, wherein the inlet end of the exhaust section is coaxially fixedly connected to the outlet end of the grate stator ring, and a tubular rectifier is coaxially arranged in the exhaust section, and the tubular rectifier mainly consists of a plurality of rectifier circular tubes adjacent to each other;

[0011] A flow meter is disposed in the exhaust section and downstream of the tubular rectifier.

[0012] Furthermore, the grate rotor disk and the air intake inner casing are movably sealed and connected via at least one grate structure.

[0013] Furthermore, a rectifying baffle is provided between the air intake outer casing and the air intake inner casing.

[0014] Furthermore, an inlet total temperature probe for measuring the total temperature of the inlet airflow of the test grate teeth is installed on the outer casing of the air intake section downstream of the rectifying baffle.

[0015] Furthermore, there are three inlet total temperature probes, which are located in the same axial section. The circumferential angle between two adjacent inlet total temperature probes is 120°, and the minimum distance between the sensing end of the inlet total temperature probe and the inner wall surface of the air intake outer casing is 10.0 mm.

[0016] Furthermore, an inlet airflow total pressure probe and a grate tooth cavity static pressure tube are installed on the grate stator ring in sequence along the airflow direction. The inlet airflow total pressure probe is used to measure the inlet airflow total pressure of the test grate, and the grate tooth cavity static pressure tube is used to measure the outlet airflow static pressure of the test grate.

[0017] To achieve the above technical effects, the present invention further provides a grate leakage test method suitable for low Reynolds number flow. The method is based on the grate leakage test device described above and comprises:

[0018] Installing the test grate on the grate rotor disc, and driving the grate rotor disc to rotate at a speed corresponding to the test working condition of the test grate;

[0019] Input the test airflow in different states from the air inlet section, measure the static pressure at the outlet of the test grate teeth, and measure the airflow rate at the exhaust section using a flow meter;

[0020] According to the performance parameters of the test airflow, the Taylor number and Reynolds number of the test grate leakage airflow under different test airflow states are analyzed and obtained;

[0021] The exhaust flow rate measured by the flow meter is used as the airflow leakage of the test grate. Based on the structural parameters of the test grate and the state parameters of the test airflow in the intake section, a leakage analysis model based on the Taylor number and Reynolds number of the test grate is constructed.

[0022] According to the structural parameters of the grate teeth to be analyzed and the grate teeth inlet and outlet airflow state parameters and the working speed under the working conditions to be analyzed, the airflow leakage of the grate teeth to be analyzed is obtained by using the leakage analysis model.

[0023] Furthermore, the leakage analysis model constructed is ,in To test the leakage of the grate teeth, is the tooth tip width of the test grate teeth, is the radial clearance of the tooth tip of the test grate teeth, is the Taylor number, is the Reynolds number, is the gas constant, is the total temperature of the airflow at the test grate inlet, is the radial height of the tooth tip of the test grate teeth, is the total airflow pressure at the test grate inlet, is the number of teeth of the test grate, is the tooth pitch of the test grate teeth, To test the static pressure of the airflow at the grate outlet, 、 are fitting parameters obtained by data fitting.

[0024] Compared with the existing technology, the beneficial effects of the present invention are: the present invention uses a tubular rectifier to first rectify the airflow of the test grate leakage, and then performs flow measurement, which can suppress the measurement errors caused by airflow rotation and uneven airflow distribution under low Reynolds number conditions, thereby improving the measurement accuracy of the leakage airflow flow under low Reynolds number conditions, facilitating the effective implementation of the grate flow characteristic test under low Reynolds number conditions, to support the grate sealing design and accurate analysis of leakage under low Reynolds number conditions, and avoid the problem of large errors in the existing grate leakage analysis method under low Reynolds number conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 Schematic diagram of the structure of a grate leakage test device suitable for low Reynolds number flow in an embodiment;

[0026] Figure 2 Schematic diagram of the fitting clearance between the test grate and the grate teeth stator ring in the embodiment;

[0027] Among them, 1. Intake outer casing; 2. Intake inner casing; 3. Grate stator ring; 4. Grate rotor disk; 5. Test grate; 6. Exhaust section; 7. Tubular rectifier; 8. Flow meter; 9. Grate structure; 10. Rectification baffle; 11. Inlet total temperature probe; 12. Inlet airflow total pressure probe; 13. Grate tooth cavity static pressure tube. DETAILED DESCRIPTION

[0028] The present invention will be described in further detail below with reference to the embodiments and accompanying drawings. However, this should not be construed as limiting the scope of the present invention to the following embodiments, as all technologies implemented based on the present invention fall within the scope of the present invention.

[0029] Example

[0030] See also Figure 1-Figure 2 , a grate leakage test device suitable for low Reynolds number flow, comprising:

[0031] An air intake section, comprising an air intake outer casing 1 and an air intake inner casing 2 arranged coaxially;

[0032] A grate stator ring 3, wherein the grate stator ring 3 is coaxially fixedly connected to the outlet end of the air intake outer casing 1;

[0033] A grate rotor disc 4, the grate rotor disc 4 being coaxially arranged with the grate stator ring 3 and located inside the grate stator ring 3, the grate rotor disc 4 being further provided with test grate teeth 5 that are clearance-matched with the grate stator ring 3, and the grate rotor disc 4 being movably and sealedly connected to the intake inner casing 2;

[0034] An exhaust section 6, the inlet end of the exhaust section 6 is coaxially fixedly connected to the outlet end of the grate stator ring 3, and a tubular rectifier 7 is coaxially arranged in the exhaust section 6. The tubular rectifier 7 mainly consists of a plurality of adjacent rectifier circular tubes;

[0035] The flow meter 8 is disposed in the exhaust section 6 and downstream of the tubular rectifier 7 .

[0036] In this embodiment, compressed air enters the air intake section of the grate leakage test device, and then the leaked air passes through the test grate 5 and enters the exhaust section 6. After being rectified by the tubular rectifier 7 installed in the circular tube at the rear end of the exhaust section 6, the flow rate of the leaked air from the test grate 5 is measured using a flow meter 8. By installing the tubular rectifier 7 in the exhaust section 6 and first rectifying the airflow leaking from the test grate 5 using the tubular rectifier 7 before performing flow measurement, the measurement error caused by airflow rotation and uneven airflow distribution under low Reynolds number conditions can be suppressed, thereby improving the accuracy of leakage airflow flow measurement under low Reynolds number conditions, facilitating the effective implementation of grate flow characteristic tests under low Reynolds number conditions, supporting the accurate analysis of grate seal design and leakage under low Reynolds number conditions, and avoiding the problem of large errors in existing grate leakage analysis methods under low Reynolds number conditions.

[0037] In this embodiment, the grate rotor disk 4 and the intake inner casing 2 are movably sealed by at least one grate structure 9, thereby realizing a relatively movable seal between the grate rotor disk 4 and the fixed intake inner casing 2. While satisfying the rotation of the grate rotor disk 4, the sealing effect between the grate rotor disk 4 and the intake inner casing 2 is improved, thereby ensuring the accuracy of the test data of the leakage of the test grate 5 and ensuring that the grate leakage test device can perform more accurate and reliable grate flow characteristic tests under low Reynolds number conditions.

[0038] In this embodiment, a rectifying baffle 10 is further provided between the air intake outer casing 1 and the air intake inner casing 2. The airflow entering the air intake section is rectified in advance by the rectifying baffle 10, so that the flow field becomes more stable, thereby reducing the measurement error caused by unstable airflow.

[0039] In this embodiment, an inlet total temperature probe 11 for measuring the total temperature of the inlet airflow of the test grate 5 is installed on the outer casing of the air intake section downstream of the rectifying baffle 10. There are three inlet total temperature probes 11, and the three inlet total temperature probes 11 are located in the same axial section. The circumferential angle between two adjacent inlet total temperature probes 11 is 120°, and the minimum distance between the sensing end of the inlet total temperature probe 11 and the inner wall surface of the air intake outer casing 1 is 10.0 mm. The provision of three inlet total temperature probes 11 not only improves the redundancy of the measurement and enhances the reliability of the data, but also effectively captures slight changes in the airflow temperature, ensuring a comprehensive and accurate measurement of the total temperature of the inlet airflow of the test grate 5. By setting the minimum distance between the inlet total temperature probe 11 and the inner wall surface of the air intake outer casing 1 to 10.0 mm, it is ensured that the probe can accurately sense the airflow temperature and avoids airflow interference caused by too close a distance, thereby ensuring the accuracy of the measurement results.

[0040] In this embodiment, an inlet airflow total pressure probe 12 and a grate tooth cavity static pressure tube 13 are installed in sequence on the grate stator ring 3 along the airflow direction. The inlet airflow total pressure probe 12 is used to measure the inlet airflow total pressure of the test grate 5, and the grate tooth cavity static pressure tube 13 is used to measure the outlet airflow static pressure of the test grate 5, so as to ensure that the pressure information of the inlet airflow and outlet airflow of the test grate 5 can be accurately captured, providing key data support for accurately evaluating the grate leakage.

[0041] It should be noted that other structures for measuring air flow temperature and pressure are also applicable to the present invention.

[0042] like Figure 1 A schematic diagram of the rotating cross-section structure of a grate leakage test device is shown. The dashed line in the figure represents the central axis (also known as the rotation axis), and the arrow indicates the primary airflow direction. In this embodiment, the exhaust section 6 transitions from a trumpet-shaped front end to a circular tube at the rear end. The tubular rectifier 7 is installed within the rear end of the exhaust section 6. The tubular rectifier 7 consists of a set of adjacent rectifier tubes. The flowmeter 8 is installed within the rear end of the exhaust section 6, behind the tubular rectifier 7.

[0043] Based on the same inventive concept, this embodiment also provides a grate leakage test method suitable for low Reynolds number flow, comprising:

[0044] Step 1: Install the test grate 5 on the grate rotor disc 4, and drive the grate rotor disc 4 to rotate at a speed corresponding to the test working condition of the test grate 5;

[0045] Step 2: Input the test airflow in different states from the air inlet section, measure the outlet static pressure of the test grate teeth 5, and measure the airflow rate of the exhaust section 6 through the flow meter 8;

[0046] Step 3: Analyze and obtain the Taylor number and Reynolds number of the leakage airflow of the test grate 5 under different test airflow states according to the performance parameters of the test airflow;

[0047] The calculation method of Reynolds number is well known to those skilled in the art, and the method for obtaining the Reynolds number under the corresponding state test airflow in this embodiment will not be repeated. pass The analysis obtained The airflow density at the inlet of test grate 5 is: To test the angular velocity of the grate rotor disc 4 of the grate 5, To test the dynamic viscosity of the airflow at the inlet of grate 5, To test the radial clearance of the tooth tip of the grate teeth 5, is the radial height of the tooth tip of the test grate teeth 5.

[0048] Step 4: Using the airflow rate of the exhaust section 6 measured by the flowmeter 8 as the airflow leakage of the test grate 5, and based on the structural parameters of the test grate 5 and the state parameters of the test airflow in the intake section, construct a leakage analysis model based on the Taylor number and Reynolds number of the test grate 5;

[0049] In this embodiment, the leakage analysis model constructed is ,in To test the leakage of grate 5, is the tooth tip width of the test grate teeth 5, To test the radial clearance of the tooth tip of the grate teeth 5, is the Taylor number, is the Reynolds number, is the gas constant, is the total temperature of the inlet airflow of the test grate 5, is the radial height of the tooth tip of the test grate teeth 5, is the total airflow pressure at the inlet of test grate 5, is the number of teeth of the test grate 5, is the tooth pitch of the test grate 5, To test the static pressure of the airflow at the inlet of grate 5, 、 The fitting parameters are obtained by fitting the experimental test data. In this embodiment, the fitting method can be used to determine the unknown coefficients in the grate leakage analysis method suitable for low Reynolds number flow. The obtained analysis model introduces the Reynolds number and Taylor number, which can ensure that the constructed model conforms to the grate leakage law under low Reynolds number, so that the airflow leakage under low Reynolds number can be accurately analyzed.

[0050] Step 5: According to the structural parameters of the grate to be analyzed and the grate inlet and outlet airflow state parameters and the operating speed under the working condition to be analyzed, the leakage analysis model is used to analyze and obtain the airflow leakage of the grate to be analyzed.

[0051] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A grate leakage test device suitable for low Reynolds number flow, characterized in that: include: An air intake section, the air intake section comprising a coaxially arranged air intake outer casing and an air intake inner casing, a rectifying baffle being further provided between the air intake outer casing and the air intake inner casing, and an inlet total temperature probe for measuring the total temperature of the airflow at the inlet of the test grate being installed on the air intake outer casing downstream of the rectifying baffle; A grate stator ring, the grate stator ring is coaxially fixedly connected to the outlet end of the air intake outer casing, and an inlet airflow total pressure probe and a grate tooth cavity static pressure tube are sequentially installed on the grate stator ring along the airflow direction. The inlet airflow total pressure probe is used to measure the inlet airflow total pressure of the test grate, and the grate tooth cavity static pressure tube is used to measure the outlet airflow static pressure of the test grate; A grate rotor disc, the grate rotor disc and the grate stator ring are coaxially arranged, and the grate rotor disc is located inside the grate stator ring. The grate rotor disc is further provided with test grate teeth that are clearance-matched with the grate stator ring. The grate rotor disc is movably and sealedly connected to the intake inner casing; An exhaust section, wherein the inlet end of the exhaust section is coaxially fixedly connected to the outlet end of the grate stator ring, and a tubular rectifier is coaxially arranged in the exhaust section, and the tubular rectifier mainly consists of a plurality of rectifier circular tubes adjacent to each other; A flow meter is disposed in the exhaust section and downstream of the tubular rectifier.

2. The comb teeth leakage test device according to claim 1, characterized in that: The grate rotor disk and the air intake inner casing are movably sealed and connected via at least one grate structure.

3. The comb teeth leakage test device according to claim 1, characterized in that: There are three inlet total temperature probes, which are located in the same axial section. The circumferential angle between two adjacent inlet total temperature probes is 120°, and the minimum distance between the sensing end of the inlet total temperature probe and the inner wall of the intake outer casing is 10.0 mm.

4. A grate leakage test method suitable for low Reynolds number flow, the method being based on the grate leakage test device according to claim 1, characterized in that: include: Installing the test grate on the grate rotor disc, and driving the grate rotor disc to rotate at a speed corresponding to the test working condition of the test grate; Input the test airflow in different states from the air inlet section, measure the static pressure at the outlet of the test grate teeth, and measure the airflow rate at the exhaust section using a flow meter; According to the performance parameters of the test airflow, the Taylor number and Reynolds number of the test grate leakage airflow under different test airflow states are analyzed and obtained; The exhaust flow rate measured by the flow meter is used as the test grate leakage rate. Based on the structural parameters of the test grate and the state parameters of the test airflow in the intake section, a leakage analysis model based on the Taylor number and Reynolds number of the test grate is constructed. According to the structural parameters of the grate to be analyzed and the airflow state parameters and the rotation speed of the air inlet section of the grate to be analyzed under the working conditions to be analyzed, the leakage analysis model is used to analyze and obtain the grate leakage of the grate to be analyzed.

5. The grate leakage test method according to claim 4, characterized in that: The leakage analysis model constructed is ,in To test the leakage of the grate teeth, is the tooth tip width of the test grate teeth, is the radial clearance of the tooth tip of the test grate teeth, is the Taylor number, is the Reynolds number, is the gas constant, is the total temperature of the airflow at the test grate inlet, is the radial height of the tooth tip of the test grate teeth, is the total airflow pressure at the test grate inlet, is the number of teeth of the test grate, is the tooth pitch of the test grate teeth, To test the static pressure of the airflow at the grate outlet, 、 are fitting parameters obtained by data fitting.

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