Grate leakage test device and method suitable for low Reynolds number flow

Abstract

The invention relates to the technical field of aero-engines, and discloses a labyrinth leakage rate test device and method suitable for low Reynolds number flow, the test device comprises an air inlet section, a labyrinth stator ring, a labyrinth rotor disc, an exhaust section and a flow meter, the tubular rectifier is mainly composed of a plurality of rectification circular tubes which are adjacent to one another. According to the invention, the tubular rectifier is arranged in the exhaust section, the flow leaked by the test labyrinth is rectified by using the tubular rectifier, and then flow measurement is carried out, so that measurement errors caused by airflow rotation and uneven airflow distribution under the condition of low Reynolds number can be inhibited; therefore, the flow measurement accuracy of the leakage airflow under the condition of the low Reynolds number is improved, a labyrinth flow characteristic test under the condition of the low Reynolds number can be conveniently and effectively carried out, labyrinth sealing design and accurate analysis of the leakage rate under the condition of the low Reynolds number are supported, and the problem that an existing labyrinth leakage analysis method is large in error under the condition of the low Reynolds number is avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of aeroengines, and discloses a labyrinth leakage measurement device and method applicable to low Reynolds number flow. Background Art

[0002] A labyrinth is an effective and long-life non-contact sealing structure, which is widely used in engines and other rotating machinery. Such a sealing structure is the most important throttling element in the internal flow air system of an aeroengine, and mainly functions to reduce the leakage amount of cooling air flow from the high-pressure area to the low-pressure area, adjust the chamber pressure, etc., so as to ensure the normal operation of the aeroengine within the entire flight envelope.

[0003] With the broadening of the working envelope of aeroengines, in the working state of extremely low intake pressure and intake flow rate, it is necessary to consider the influence of low Reynolds number effects on the flow field. For the labyrinth sealing structure, the low Reynolds number flow inside it will cause significant changes in the sealing performance. The existing labyrinth leakage measurement system does not have the measurement ability under low Reynolds number conditions, resulting in the inability to accurately evaluate the performance of the labyrinth sealing structure in extreme working environments. Summary of the Invention

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

[0005] In order to achieve the above technical effects, the technical solution adopted by the present invention is as follows: A labyrinth leakage measurement device applicable to low Reynolds number flow, comprising: An intake section, the intake section includes an intake outer casing and an intake inner casing arranged coaxially; A labyrinth stator ring, the labyrinth stator ring is coaxially and fixedly connected to the outlet end of the intake outer casing; A labyrinth rotor disk, the labyrinth rotor disk is coaxially arranged with the labyrinth stator ring, and the labyrinth rotor disk is located inside the labyrinth stator ring. The labyrinth rotor disk is also provided with a test labyrinth in clearance fit with the labyrinth stator ring, and the labyrinth rotor disk is movably and sealingly connected to the intake inner casing; An exhaust section, the inlet end of the exhaust section is coaxially and fixedly connected to the outlet end of the labyrinth stator ring. A tubular rectifier is coaxially arranged inside the exhaust section, and the tubular rectifier is mainly composed of a plurality of mutually adjacent rectifying circular tubes; A flowmeter, the flowmeter is arranged inside the exhaust section and is located downstream of the tubular rectifier.

[0006] Further, the labyrinth rotor disk and the inner intake casing are movably and sealingly connected through at least one labyrinth structure.

[0007] Further, a rectifying partition is also arranged between the outer intake casing and the inner intake casing.

[0008] Further, an inlet total temperature probe for measuring the total temperature of the inlet air flow of the test labyrinth is installed on the outer casing of the intake section downstream of the rectifying partition.

[0009] Further, there are three inlet total temperature probes. The three inlet total temperature probes are in the same axial section, and the circumferential angle between two adjacent inlet total temperature probes is 120°. The minimum distance between the sensing end of the inlet total temperature probe and the inner wall surface of the outer intake casing is 10.0 mm.

[0010] Further, an inlet air flow total pressure probe and a labyrinth tooth cavity static pressure tube are successively installed on the labyrinth stator ring along the air flow direction. The inlet air flow total pressure probe is used to measure and obtain the total pressure of the inlet air flow of the test labyrinth, and the labyrinth tooth cavity static pressure tube is used to measure and obtain the static pressure of the outlet air flow of the test labyrinth.

[0011] To achieve the above technical effects, the present invention also provides a labyrinth leakage amount test method applicable to low Reynolds number flow. Based on the labyrinth leakage amount test device described above, the method includes: Install the test labyrinth on the labyrinth rotor disk and drive the labyrinth rotor disk to rotate at the rotation speed corresponding to the test conditions of the test labyrinth. Input test air flows in different states from the intake section, measure the static pressure at the outlet of the test labyrinth, and measure the air flow rate in the exhaust section through a flow meter. According to the performance parameters of the test air flow, analyze and obtain the Taylor number and Reynolds number of the leakage air flow of the test labyrinth under test air flows in different states. Take the air flow rate measured by the flow meter in the exhaust section as the air flow leakage amount of the test labyrinth. Based on the structural parameters of the test labyrinth and the state parameters of the test air flow in the intake section, construct a leakage amount analysis model based on the Taylor number and Reynolds number of the test labyrinth. According to the structural parameters of the labyrinth to be analyzed, the air flow state parameters at the inlet and outlet of the labyrinth and the operating rotation speed under the working conditions to be analyzed, use the leakage amount analysis model to analyze and obtain the air flow leakage amount of the labyrinth to be analyzed.

[0012] Further, the constructed leakage amount analysis model is , where is the leakage amount of the test labyrinth, is the tip width of the test labyrinth, is the tip radial clearance of the test labyrinth, is the Taylor number, is the Reynolds number, is the gas constant, is the total temperature of the inlet air flow of the test labyrinth, is the radial height of the tip of the test labyrinth, is the total pressure of the inlet air flow of the test labyrinth, is the number of teeth of the test labyrinth, is the pitch of the teeth of the test labyrinth, is the static pressure of the outlet air flow of the test labyrinth, 、 are fitting parameters obtained by data fitting.

[0013] Compared with the prior art, the beneficial effects of the present invention are as follows: The present invention first rectifies the air flow leaked from the test labyrinth by using a tubular rectifier and then measures the flow rate, which can suppress the measurement errors caused by the air flow rotation and uneven air flow distribution under low Reynolds number conditions, thereby improving the measurement accuracy of the leakage air flow rate under low Reynolds number conditions, facilitating the effective development of the labyrinth flow rate characteristic test under low Reynolds number conditions to support the labyrinth seal design and accurate analysis of the leakage amount under low Reynolds number conditions, and avoiding the problem of large errors in the existing labyrinth leakage analysis method under low Reynolds number conditions. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic structural diagram of a labyrinth leakage amount test device applicable to low Reynolds number flow in the embodiment; Figure 2 is a schematic diagram of the clearance between the test labyrinth and the labyrinth stator ring in the embodiment; Among them, 1, intake outer casing; 2, intake inner casing; 3, labyrinth stator ring; 4, labyrinth rotor disk; 5, test labyrinth; 6, exhaust section; 7, tubular rectifier; 8, flow meter; 9, labyrinth structure; 10, rectifying partition; 11, inlet total temperature probe; 12, inlet air flow total pressure probe; 13, labyrinth tooth cavity static pressure pipe. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0015] The present invention will be further described in detail below in conjunction with the embodiments and the drawings. However, it should not be understood that the scope of the above-mentioned subject matter of the present invention is limited to the following embodiments. All technologies implemented based on the content of the present invention belong to the scope of the present invention.

[0016] Embodiment See Figure 1 - Figure 2 , a labyrinth leakage amount test device applicable to low Reynolds number flow, comprising: An intake section, the intake section includes an intake outer casing 1 and an intake inner casing 2 arranged coaxially; A labyrinth stator ring 3, the labyrinth stator ring 3 is fixedly connected coaxially to the outlet end of the intake outer casing 1; A labyrinth rotor disk 4, the labyrinth rotor disk 4 is coaxially arranged with the labyrinth stator ring 3, and the labyrinth rotor disk 4 is located inside the labyrinth stator ring 3. A test labyrinth 5 which is in clearance fit with the labyrinth stator ring 3 is further arranged on the labyrinth rotor disk 4. The labyrinth rotor disk 4 is movably and sealingly connected with the intake inner casing 2; An exhaust section 6, the inlet end of the exhaust section 6 is coaxially and fixedly connected with the outlet end of the labyrinth stator ring 3. A tubular rectifier 7 is coaxially arranged in the exhaust section 6. The tubular rectifier 7 is mainly composed of a plurality of rectifying circular tubes adjacent to each other; A flowmeter 8, the flowmeter 8 is arranged in the exhaust section 6 and is located downstream of the tubular rectifier 7.

[0017] In this embodiment, compressed air enters the intake section of the labyrinth leakage amount test device. Subsequently, the leaked air passing through the test labyrinth 5 enters the exhaust section 6. After being rectified by the tubular rectifier 7 installed in the rear-end circular tube of the exhaust section 6, the flow measurement of the leaked air of the test labyrinth 5 is completed by using the flowmeter 8. By arranging the tubular rectifier 7 in the exhaust section 6 and rectifying the airflow leaked from the test labyrinth 5 by the tubular rectifier 7 first and then performing the flow measurement, the measurement errors caused by the airflow rotation and uneven airflow distribution under low Reynolds number conditions can be suppressed. Thus, the measurement accuracy of the leaked airflow flow under low Reynolds number conditions is improved, which is convenient for effectively carrying out the labyrinth flow characteristic test under low Reynolds number conditions to support the labyrinth seal design and accurate analysis of the leakage amount under low Reynolds number conditions, and avoid the problem of large errors in the existing labyrinth leakage analysis method under low Reynolds number conditions.

[0018] In this embodiment, the labyrinth rotor disk 4 and the intake inner casing 2 are movably and sealingly connected through at least one labyrinth structure 9, realizing the relative movable seal between the labyrinth rotor disk 4 and the fixedly arranged intake inner casing 2. While satisfying the rotation of the labyrinth rotor disk 4, the sealing effect between the labyrinth rotor disk 4 and the intake inner casing 2 is improved, ensuring the accuracy of the test data of the leakage amount of the test labyrinth 5, and ensuring that the labyrinth leakage amount test device can carry out more accurate and reliable labyrinth flow characteristic tests under low Reynolds number conditions.

[0019] In this embodiment, a rectifying partition 10 is further arranged between the intake outer casing 1 and the intake inner casing 2. The airflow entering the intake section is pre-rectified by the rectifying partition 10, making the flow field more stable and reducing the measurement errors caused by unstable airflow.

[0020] In this embodiment, an inlet total temperature probe 11 for measuring the total temperature of the inlet air flow of the test labyrinth 5 is installed on the outer casing of the air inlet section downstream of the rectifying partition 10. There are three inlet total temperature probes 11, and the three inlet total temperature probes 11 are in the same axial section. The circumferential angle between two adjacent inlet total temperature probes 11 is 120°. The minimum distance between the sensing end of the inlet total temperature probe 11 and the inner wall surface of the air inlet outer casing 1 is 10.0 mm. The setting of the three inlet total temperature probes 11 not only improves the redundancy of measurement, enhances the reliability of data, but also can effectively capture the slight changes in the air flow temperature, and can ensure a comprehensive and accurate measurement of the total temperature of the inlet air flow of the test labyrinth 5. By setting the minimum distance between the inlet total temperature probe 11 and the inner wall surface of the air inlet outer casing 1 to 10.0 mm, it not only ensures that the probe can accurately sense the air flow temperature, but also avoids the air flow interference caused by too close a distance, thus ensuring the accuracy of the measurement result.

[0021] In this embodiment, an inlet air flow total pressure probe 12 and a labyrinth tooth cavity static pressure tube 13 are sequentially installed on the labyrinth stator ring 3 along the air flow direction. The inlet air flow total pressure probe 12 is used to measure and obtain the total pressure of the inlet air flow of the test labyrinth 5, and the labyrinth tooth cavity static pressure tube 13 is used to measure and obtain the static pressure of the outlet air flow of the test labyrinth 5, so as to ensure that the pressure information of the inlet air flow and the outlet air flow of the test labyrinth 5 can be accurately captured, providing key data support for accurately evaluating the labyrinth leakage amount.

[0022] It should be noted that other structures for measuring the air flow temperature and pressure are also applicable to the present invention.

[0023] As Figure 1 shows a schematic diagram of the rotary cross-section structure of the labyrinth leakage amount test device. The dotted line in the figure is the central axis (i.e., the rotary shaft), and the arrow direction is the main air flow direction. In this embodiment, the exhaust section 6 transitions from a front-end bell shape to a rear-end round tube. The tubular rectifier 7 is installed in the round tube at the rear end of the exhaust section 6. The tubular rectifier 7 is composed of a group of rectifying round tubes adjacent to each other. The flowmeter 8 is installed in the round tube at the rear end of the exhaust section 6 and is located behind the tubular rectifier 7.

[0024] Based on the same inventive concept, this embodiment also provides a labyrinth leakage amount test method applicable to low Reynolds number flow, including: Step 1: Install the test labyrinth 5 on the labyrinth rotor disk 4 and drive the labyrinth rotor disk 4 to rotate at the rotation speed corresponding to the test working condition of the test labyrinth 5. Step 2: Input test air flows in different states from the air inlet section, measure the static pressure at the outlet of the test labyrinth 5, and measure the air flow rate of the exhaust section 6 through the flowmeter 8. Step 3. According to the performance parameters of the test air flow, analyze and obtain the Taylor number and Reynolds number of the leakage air flow of the test labyrinth 5 under different state test air flows; The calculation method of the Reynolds number is well-known to those skilled in the art. In this embodiment, the method for obtaining the Reynolds number corresponding to the state test air flow will not be elaborated. The Taylor number corresponding to the state test air flow is obtained through analysis, where is the inlet air flow density of the test labyrinth 5, is the angular velocity of the labyrinth rotor disk 4 of the test labyrinth 5, is the dynamic viscosity of the inlet air flow of the test labyrinth 5, is the tip radial clearance of the test labyrinth 5, is the tip radial height of the test labyrinth 5.

[0025] Step 4. Take the air flow rate of the exhaust section 6 measured by the flow meter 8 as the air flow leakage amount of the test labyrinth 5, and based on the structural parameters of the test labyrinth 5 and the state parameters of the inlet section test air flow, construct a leakage amount analysis model based on the Taylor number and Reynolds number of the test labyrinth 5; In this embodiment, the constructed leakage amount analysis model is , where is the leakage amount of the test labyrinth 5, is the tip width of the test labyrinth 5, is the tip radial clearance of the test labyrinth 5, is the Taylor number, is the Reynolds number, is the gas constant, is the total temperature of the inlet air flow of the test labyrinth 5, is the tip radial height of the test labyrinth 5, is the total pressure of the inlet air flow of the test labyrinth 5, is the number of teeth of the test labyrinth 5, is the tooth pitch of the test labyrinth 5, is the static pressure of the inlet air flow of the test labyrinth 5, 、 are fitting parameters obtained by fitting the test data. In this embodiment, the fitting method can be used to determine the undetermined coefficients in the analysis method of the labyrinth leakage amount applicable to 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 labyrinth leakage law under low Reynolds number, so as to accurately analyze and obtain the air flow leakage amount under low Reynolds number.

[0026] Step 5. According to the structural parameters of the labyrinth to be analyzed, the state parameters of the inlet and outlet air flows of the labyrinth and the working speed under the working conditions to be analyzed, use the leakage amount analysis model to analyze and obtain the air flow leakage amount of the labyrinth to be analyzed.

[0027] The above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A labyrinth leakage test device applicable to low Reynolds number flows, characterized in that, Comprising: An intake section, the intake section including an outer intake casing and an inner intake casing arranged coaxially; A labyrinth stator ring, the labyrinth stator ring being coaxially and fixedly connected to the outlet end of the outer intake casing; A labyrinth rotor disk, the labyrinth rotor disk being coaxially arranged with the labyrinth stator ring, and the labyrinth rotor disk being located inside the labyrinth stator ring. A test labyrinth is further provided on the labyrinth rotor disk and is in clearance fit with the labyrinth stator ring. The labyrinth rotor disk is movably and sealingly connected to the inner intake casing; An exhaust section, the inlet end of the exhaust section being coaxially and fixedly connected to the outlet end of the labyrinth stator ring. A tubular rectifier is coaxially arranged inside the exhaust section, and the tubular rectifier is mainly composed of a plurality of rectifying round tubes adjacent to each other; A flowmeter, the flowmeter being arranged inside the exhaust section and located downstream of the tubular rectifier.

2. The labyrinth leakage rate test device according to claim 1, wherein The labyrinth rotor disk and the inner intake casing are movably and sealingly connected through at least one labyrinth structure.

3. The labyrinth leakage rate test device according to claim 1, wherein A rectifying partition is further arranged between the outer intake casing and the inner intake casing.

4. The labyrinth leakage rate test device according to claim 3, characterized in that, An inlet total temperature probe for measuring the total temperature of the inlet air flow of the test labyrinth is installed on the outer casing of the intake section downstream of the rectifying partition.

5. The labyrinth leakage test device according to claim 4, characterized in that, There are three inlet total temperature probes. The three inlet total temperature probes are in the same axial section. The circumferential angle between two adjacent inlet total temperature probes is 120°. The minimum distance between the sensing end of the inlet total temperature probe and the inner wall surface of the outer intake casing is 10.0 mm.

6. The labyrinth leakage rate test device according to claim 1, characterized in that, An inlet air flow total pressure probe and a labyrinth tooth cavity static pressure tube are sequentially installed on the labyrinth stator ring along the air flow direction. The inlet air flow total pressure probe is used to measure and obtain the total pressure of the inlet air flow of the test labyrinth, and the labyrinth tooth cavity static pressure tube is used to measure and obtain the static pressure of the outlet air flow of the test labyrinth.

7. A labyrinth leakage flow rate test method applicable to low Reynolds number flows, which is based on the labyrinth leakage flow rate test device described in claim 1, and is characterized in that, Comprising: Install the test labyrinth on the labyrinth rotor disk and drive the labyrinth rotor disk to rotate at the speed corresponding to the test condition of the test labyrinth; Input test air flows in different states from the intake section, measure the outlet static pressure of the test labyrinth, and measure the air flow rate of the exhaust section through the flowmeter; Analyze and obtain the Taylor number and Reynolds number of the leakage air flow of the test labyrinth under test air flows in different states according to the performance parameters of the test air flow; Take the air flow rate of the exhaust section measured by the flowmeter as the air flow leakage amount of the test labyrinth, and construct a leakage amount analysis model based on the Taylor number and Reynolds number of the test labyrinth based on the structural parameters of the test labyrinth and the state parameters of the test air flow in the intake section; Analyze and obtain the air flow leakage amount of the labyrinth to be analyzed by using the leakage amount analysis model according to the structural parameters of the labyrinth to be analyzed, the air flow state parameters at the inlet and outlet of the labyrinth and the working speed under the condition to be analyzed.

8. The labyrinth leakage rate test method according to claim 7, characterized in that The constructed leakage analysis model is , where is the leakage of the test labyrinth tooth,[ is the tip width of the test labyrinth tooth,[ is the tip radial clearance of the test labyrinth tooth,[ is the Taylor number,[ is the Reynolds number,[ is the gas constant,[ is the total inlet gas temperature of the test labyrinth tooth,[ is the tip radial height of the test labyrinth tooth,[ is the total inlet gas pressure of the test labyrinth tooth,[ is the number of teeth of the test labyrinth tooth,[ is the tooth pitch of the test labyrinth tooth,[ is the static pressure of the outlet gas of the test labyrinth tooth,[ , are fitting parameters obtained by data fitting.[

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