Test method and test device for the effect of full-circle straight-through grate tooth sealing gap on leakage

Abstract

The present invention discloses a method and device for testing the effect of the sealing gap of a full-circle straight-through grate on leakage. By designing an equivalent test piece, the test method can conveniently and equivalently adjust the sealing gap without replacing the test piece, thereby equivalently testing the effect of different sealing gaps on grate leakage. The test device includes a base, a base cover, a movable seat, a gap adjustment device, an air supply device, a pressure sensor, and a temperature sensor, which can provide an experimental environment for leakage testing and conveniently adjust the sealing gap. The method and device for testing the effect of the sealing gap of a full-circle straight-through grate on leakage can achieve equivalent testing of the effect of the sealing gap of a full-circle straight-through grate on leakage.

Description

Technical Field

[0001] The invention relates to the fields of sealing testing technology and experimental instruments, and in particular provides a method and a device for testing the influence of the sealing gap of a full-circle straight-through grate teeth on the leakage amount. Background Art

[0002] Aircraft engines, hailed as the crown jewel of industry, are a crucial reflection of a nation's scientific and defense strength. The level of sealing technology directly impacts aeroengine performance, making the design and research of sealing issues of paramount importance in science and technology. The increasingly complex operating environment of aircraft engines places higher demands on sealing structures. Research has shown that a 1% reduction in seal leakage can increase engine thrust by 1% and reduce specific fuel consumption by 0.1%, demonstrating that leakage is a key factor affecting aeroengine efficiency.

[0003] In the design of aircraft engines, the structural design of grate seals must take into account different structural forms and leakage performance. When testing the leakage performance, it is necessary to test the leakage under different sealing gaps. However, the existing test method for evaluating the effect of grate seal gap on leakage can only test the leakage under a certain static gap (such as Figure 1 If leakage under different gaps needs to be tested, test pieces of different sizes need to be replaced accordingly, and the gap cannot be dynamically monitored and adjusted in real time. If the test piece is replaced, the experimental process is relatively inefficient, and manufacturing errors and assembly errors are accumulated, resulting in low test accuracy, low operating efficiency, and high manufacturing costs.

[0004] Therefore, it is an urgent problem to propose an equivalent test method and test device for the influence of the sealing gap of the whole-circle straight-through grate teeth on the leakage volume, so as to facilitate the adjustment of the sealing gap, improve the test efficiency, improve the test accuracy and reduce the test cost. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a test method and test device for the influence of the sealing gap of a full-circle straight-through comb tooth on the leakage volume, so as to solve the problem that the existing test method for evaluating the influence of the sealing gap of the comb tooth on the leakage volume is not convenient for dynamically adjusting the sealing gap.

[0006] In one aspect, the present invention provides a method for testing the effect of the sealing gap of a full-circle straight-through grate on leakage, comprising the following steps:

[0007] Step 1: Design an equivalent test piece of the full-circle straight-through grate test piece, wherein the outer circumference of the full-circle straight-through grate test piece is provided with grate teeth at intervals, and the equivalent test piece includes an annular body, and one side end face of the annular body is provided with multiple circles of annular teeth from the inside to the outside, and the annular teeth are coaxially arranged with the annular body. The tooth shape, height, number of teeth and spacing between adjacent annular teeth of the annular teeth are consistent with the tooth shape, height, number of teeth and spacing between adjacent grate teeth on the full-circle straight-through grate test piece. The equivalent radius r1 of the innermost circle tooth of the annular teeth is calculated by the following formula:

[0008]

[0009] Wherein, r1 is the equivalent radius of the innermost ring tooth of the annular tooth, that is, the distance between the inner side surface of the innermost ring tooth of the annular tooth and the central axis of the annular body, z is the number of teeth on the full-circle straight-through grate tooth test piece, r is the radius of the full-circle straight-through grate tooth test piece, and t is the tooth pitch of adjacent grate teeth on the full-circle straight-through grate tooth test piece, where the tooth pitch refers to the distance between the same sides of adjacent grate teeth;

[0010] Step 2: Use the equivalent test piece to replace the full-circumference straight-through comb test piece, and use the cover plate that matches the equivalent test piece to replace the stator that matches the full-circumference straight-through comb test piece to perform a leakage test. During the test, the distance between the equivalent test piece and the cover plate is equivalent to the distance between the full-circumference straight-through comb test piece and the stator. Adjusting the distance between the equivalent test piece and the cover plate is equivalent to adjusting the sealing gap between the full-circumference straight-through comb test piece and the stator.

[0011] The present invention also provides a testing device for the influence of the sealing gap of a full-circle straight-through comb tooth on the leakage amount, comprising: a base, a base cover, a movable seat, a gap adjustment device, an air supply device, a pressure sensor and a temperature sensor, wherein a chamber is provided in the middle of the base, and an air supply port is provided at the rear end, the movable seat is slidably installed in the chamber, the front end of the movable seat is used to install an equivalent test piece, the air supply device is connected to the air supply port, and is used to uniformly supply air to the chamber, the base cover is sealingly connected to the front end of the base, the middle part of the base cover has an opening, the inner side of the base cover is used to fixedly install a cover plate that cooperates with the equivalent test piece, the middle part of the cover plate is provided with an air outlet that cooperates with the opening in the middle part of the base cover, the gap adjustment device is connected to the movable seat, and is used to adjust the distance between the movable seat and the cover plate, and the pressure sensor and temperature sensor are used to detect the pressure and temperature in the chamber respectively.

[0012] Preferably, the gap adjustment device includes a servo motor, a coupling and a ball screw, wherein the servo motor is connected to the ball screw through the coupling to drive the ball screw to rotate, and the nut installed on the ball screw is fixedly connected to the rear end of the movable seat to drive the movable seat to move axially along the ball screw.

[0013] Further preferably, a plurality of guide rails are provided at intervals and in parallel on the inner wall of the base, and the outer periphery of the movable seat is connected to a slider mounted on the guide rails.

[0014] Further preferably, the air supply device includes an air compressor, an air storage tank and an air cylinder connected in sequence, and a flow meter is provided on the pipeline between the air storage tank and the air cylinder.

[0015] Further preferably, the testing device for the effect of the sealing gap of the entire circumference straight-through type comb teeth on the leakage rate further includes a displacement sensor for detecting the distance between the equivalent test piece and the cover plate.

[0016] Further preferably, the testing device for the influence of the full-circle straight-through comb tooth sealing gap on the leakage amount also includes a control system, which is connected to the gap adjustment device and the displacement sensor, and is used to control the gap adjustment device according to the distance detected by the displacement sensor, so as to achieve precise adjustment of the distance between the equivalent test piece and the cover plate.

[0017] Further preferably, the control system is also connected to the pressure sensor, temperature sensor and air supply device, for collecting the pressure and temperature collected by the pressure sensor and temperature sensor in real time, and for adjusting the air supply of the air supply device according to the detection value of the pressure sensor.

[0018] The present invention provides a test method for the influence of the sealing gap of a full-circumference straight-through type comb teeth on the leakage rate. By designing an equivalent test piece of the traditional full-circumference straight-through type comb teeth test piece, the teeth of the comb teeth test piece are set on the end face of the annular main body, replacing the structural form of the original test piece in which the teeth are set on the circumferential surface of the annular main body. The sealing gap can be conveniently adjusted by a cover plate that cooperates with it, and the influence of different gap changes on the leakage rate can be equivalently tested, thereby improving the test accuracy and reliability.

[0019] The test device for the influence of the full-circle straight-through grate tooth sealing gap on the leakage provided by the present invention can conveniently adjust the distance between the equivalent test piece and the cover plate, can evaluate the influence of the dynamic / static sealing gap on the leakage, and has high test accuracy and reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments:

[0021] Figure 1This is a schematic diagram of the installation position of the existing full-circle straight-through grate test piece and the stator;

[0022] Figure 2 A schematic diagram of the installation positions of the equivalent test piece and the cover plate used in the test method for the effect of the full-circle straight-through grate tooth sealing gap on the leakage provided by the present invention;

[0023] Figure 3 This is a schematic structural diagram of a testing device for the effect of the sealing gap of a full-circle straight-through grate on leakage provided by the present invention. DETAILED DESCRIPTION

[0024] The present invention will be further explained below with reference to specific embodiments, but the present invention is not limited thereto.

[0025] In order to solve the problem that the existing test method for evaluating the influence of the grate tooth sealing gap on the leakage is not convenient for dynamically adjusting the sealing gap, the present invention provides a test method for the influence of the full-circle straight-through grate tooth sealing gap on the leakage, comprising the following steps:

[0026] Step 1: Design an equivalent test piece 10 of the full-circle straight-through type grate test piece 40, wherein the outer circumference of the full-circle straight-through type grate test piece 40 is provided with grate teeth (such as Figure 1 As shown in FIG4 , the equivalent test piece 10 includes an annular main body 101, and a plurality of ring teeth 102 are arranged on one end surface of the annular main body 101 from the inside to the outside. The annular teeth 102 are coaxially arranged with the annular main body 101. The tooth shape, height, number of teeth and spacing between adjacent annular teeth of the annular teeth are consistent with the tooth shape, height, number of teeth and spacing between adjacent grate teeth on the full-circle straight-through grate tooth test piece 40. The equivalent radius r1 of the innermost ring tooth of the annular teeth 102 is calculated by the following formula:

[0027]

[0028] Wherein, r1 is the equivalent radius of the innermost tooth of the annular tooth 102, that is, the distance between the inner side surface of the innermost tooth of the annular tooth 102 and the central axis of the annular body 101, z is the number of teeth on the full-circle straight-through grate test piece 40, r is the radius of the full-circle straight-through grate test piece 40, and t is the tooth pitch of adjacent grate teeth on the full-circle straight-through grate test piece 40, where the tooth pitch refers to the distance between the same sides of adjacent grate teeth;

[0029] Step 2: Use the equivalent test piece 10 to replace the full-circumference straight-through comb test piece 40, and use the cover plate 20 that matches the equivalent test piece 10 to replace the stator 30 that matches the full-circumference straight-through comb test piece 40 to perform a leakage test. During the test, the distance between the equivalent test piece 10 and the cover plate 20 is equivalent to the distance between the full-circumference straight-through comb test piece 40 and the stator 30. Adjusting the distance between the equivalent test piece 10 and the cover plate 20 is equivalent to adjusting the sealing gap between the full-circumference straight-through comb test piece 40 and the stator 30.

[0030] This test method for the influence of the sealing gap of a full-circle straight-through type grate teeth on the leakage rate is based on a test piece designed to be equivalent to the full-circle straight-through type grate teeth test piece. The teeth of the grate teeth test piece are arranged on the end face of the annular main body, replacing the structural form of the original test piece in which the teeth are arranged on the circumferential surface of the annular main body. The sealing gap can be conveniently adjusted by a cover plate that cooperates with it, and the influence of different sealing gap changes on the leakage rate can be equivalently tested, thereby improving the test accuracy and reliability.

[0031] Among them, the leakage test may include a test to evaluate the influence of dynamic and static gaps on the leakage amount. In the test to evaluate the influence of dynamic gaps on the leakage amount, the gap between the equivalent test piece and the cover plate can be adjusted through the control system and the actuator, which is equivalent to adjusting the sealing gap between the full-circle straight-through comb test piece and the stator.

[0032] The derivation process of the equivalent radius r1 of the innermost ring tooth of the annular gear 102 is as follows:

[0033] According to Stodola's empirical formula, the grate teeth as a throttling element meet the following requirements:

[0034]

[0035] Where, m is the unit of theoretical leakage, unit is kg / s;

[0036] S is the flow area, unit is m 2 ;

[0037] p i , p0 is the pressure before and after the grate teeth are sealed, unit is Pa;

[0038] z is the number of grate teeth;

[0039] T i is the total inlet temperature, in K;

[0040] R is the gas constant of air, which is 287.06 J·kg -1 ·K -1 ;

[0041] k is the flow capacity coefficient, straight teeth k = 1.1 ~ 1.27, helical teeth k = 1.0 ~ 1.15.

[0042] In the traditional grate test piece structure, the grate teeth are located on the circumference of the annular test piece, and the flow area through each tooth is equal, such as Figure 1 As shown, at this time, the flow area of ​​the grate gap is usually calculated using the following formula

[0043] s=2πrc

[0044] Where, r is the radius of the traditional grate test piece, in meters;

[0045] c------Gate sealing gap between comb teeth, unit: m.

[0046] In the present invention, the position of the grate teeth on the test piece is changed, and the grate teeth are placed on the end surface of the annular test piece (such as Figure 2 As shown), at this time, the improved test piece structure has different flow areas corresponding to each tooth. According to Stoddora's empirical formula,

[0047]

[0048] Where, m is the unit of theoretical leakage, unit is kg / s;

[0049] S n is the flow area of ​​the nth tooth, in m 2 ;

[0050] p i , p0 is the pressure before and after the grate teeth are sealed, unit is Pa;

[0051] p ni , p n0 is the pressure before and after the nth grate tooth is sealed, unit: Pa;

[0052] z is the number of grate teeth.

[0053] The flow area of ​​the nth tooth of the improved test piece structure is:

[0054] s n =2πc[r1+t(n-1)]

[0055] Where r1 is the equivalent radius of the first grate tooth of the equivalent test piece, in m;

[0056] t------the distance between the same sides of adjacent comb teeth, unit: m.

[0057] Under the same gap c, the pressure P before and after the gas flow of the equivalent test piece and the original test piece is i , P o, the number of teeth z, and the leakage m are equal. Substituting into the Stoddard formula, the equivalent relationship between the first grate tooth equivalent radius r1 of the equivalent test piece and the radius r of the traditional test piece is obtained:

[0058]

[0059] Equivalent radius r n for:

[0060] r n =r1+t(n-1)

[0061] The following examples verify the accuracy of the equivalent test piece:

[0062] Take 4 sealed straight-through grate teeth as an example:

[0063] 1) According to Stoddara's empirical formula:

[0064]

[0065] Where m 2 The unit of theoretical leakage is kg / s;

[0066] S is the flow area, unit is m 2 ;

[0067] p i , p0 is the pressure before and after the grate teeth are sealed, unit is Pa;

[0068] z is the number of grate teeth, which is 4;

[0069] R is the gas constant of air, which is 287.06 J·kg -1 ·K -1 ;

[0070] T i is the total inlet temperature, which is taken as 273K;

[0071] k is the flow capacity coefficient, and for straight teeth k = 1.1.

[0072] The flow area of ​​the grate gap is usually calculated using the following formula:

[0073] s=2πrc

[0074] Where, r is the radius of the traditional grate test piece, in meters;

[0075] c------grate teeth sealing gap, unit: m;

[0076] like Figure 2 As shown in the figure, the improved test piece structure has unequal flow areas for each tooth. According to Stoddara’s empirical formula, we have:

[0077]

[0078] Where, m is the theoretical leakage rate, unit is kg / s;

[0079] S n is the flow area of ​​the nth tooth, in m 2 ;

[0080] p i , p0 is the pressure before and after the grate teeth are sealed, unit is Pa;

[0081] p ni , p n0 is the pressure before and after the nth grate tooth is sealed, unit: Pa;

[0082] z is the number of grate teeth, which is 4;

[0083] The flow area of ​​the nth tooth of the improved structure is:

[0084] s n =2πc[r1+t(n-1)]

[0085] Where, r1 is the equivalent radius of the first grate tooth of the equivalent test piece, in m;

[0086] t------the distance between the same sides of adjacent comb teeth, unit: m.

[0087] Under the same gap c, the pressure P before and after the gas flow of the equivalent test piece and the original test piece is i , P o , the number of teeth z, and the leakage m are equal. Substituting into the Stoddard formula, the equivalent relationship between the first grate tooth equivalent radius r1 of the equivalent test piece and the radius r of the traditional test piece is obtained:

[0088]

[0089] Right now:

[0090]

[0091] The parameters of the traditional test piece used in this embodiment are shown in Table 1:

[0092] Table 1 Test piece parameters

[0093] c(mm) h(mm) r(mm) t(mm) 0.2 3 150 3

[0094] Calculation shows that r1 = 145.61 mm.

[0095] That is: the equivalent radius r of each tooth n for:

[0096] r2=145.61+3×(2-1)=148.61mm

[0097] r3=145.61+3×(3-1)=151.61mm

[0098] r4=145.61+3×(4-1)=154.61mm

[0099] Afterwards, the traditional test piece and the equivalent test piece structure were modeled, and the relationship between the pressure ratio, the change in the sealing gap, and the leakage was calculated through numerical simulation to verify the accuracy of the equivalent test piece:

[0100] By changing the inlet pressure P i To change the pressure ratio during the experiment, the traditional test piece and the improved equivalent test piece were modeled using the traditional test piece radius and the calculated equivalent radius, with the sealing gaps of 0.2mm and 0.3mm respectively. The relationship between the pressure ratio and leakage of different sealing gaps was verified by numerical simulation as shown in Tables 2 and 3. P i =0.15Mpa, 0.2Mpa, 0.25Mpa, 0.3Mpa, and the pressure ratios are 1.5, 2, 2.5, and 3 respectively.

[0101] Table 2 Pressure ratio, leakage and error of traditional test piece and equivalent test piece under 0.2mm sealing gap

[0102] Pressure ratio 1.5 2 2.5 3 Leakage of traditional test piece kg / s 0.0583 0.0864 0.107 0.124 Equivalent test piece leakage kg / s 0.0571 0.0845 0.1047 0.1215 error 2.1％ 2.2％ 2.1％ 2.0％

[0103] Table 3 Pressure ratio, leakage and error of traditional test piece and equivalent test piece under 0.3mm sealing gap

[0104] Pressure ratio 1.5 2 2.5 3 Leakage of traditional test piece kg / s 0.0353 0.0513 0.0637 0.0742 Equivalent test piece leakage kg / s 0.0347 0.0504 0.0627 0.073 error 1.7％ 1.8％ 1.6％ 1.6％

[0105] From the numerical calculation results, it can be seen that when the sealing gap is 0.2mm, the leakage error of the equivalent test piece is about 2% compared with the leakage of the traditional test piece. When the sealing gap is 0.3mm, the leakage error of the equivalent test piece is about 1.7% compared with the leakage of the traditional test piece. The error is within an acceptable range.

[0106] Therefore, the above-mentioned equivalent test piece can completely replace the traditional test piece structure for leakage testing.

[0107] like Figure 3As shown, the present invention also provides a test device for the influence of the sealing gap of a full-circle straight-through grate on the leakage rate, comprising: a base 1, a base cover 2, a movable seat 3, a gap adjustment device, an air supply device, a pressure sensor 6 and a temperature sensor 7, wherein a chamber is provided in the middle of the base 1, and an air supply port is provided at the rear end, the movable seat 3 is slidably installed in the chamber, the front end of the movable seat 3 is used to install an equivalent test piece 10, the air supply device is connected to the air supply port, and is used to uniformly supply air to the chamber, the base cover 2 is sealed and connected to the front end of the base 1, the middle part of the base cover 2 is opened, the inner side of the base cover 2 is used to fix and install a cover plate 20 that cooperates with the equivalent test piece 10, the middle part of the cover plate 20 is provided with an air outlet that cooperates with the opening in the middle of the base cover 2, the gap adjustment device is connected to the movable seat 3, and is used to adjust the distance between the movable seat 3 and the cover plate 20, the pressure sensor 6 and the temperature sensor 7 are used to detect the pressure and temperature in the chamber respectively.

[0108] The method of using the test device for the influence of the sealing gap of the whole-circle straight-through comb teeth on the leakage amount is as follows: the equivalent test piece is installed at the front end of the movable seat, and the cover plate is installed at the rear end of the base cover so that the two are relatively matched. During the test, the air supply device can evenly supply air to the chamber, and the pressure in the chamber can be adjusted. The gap adjustment device can adjust the distance between the movable seat and the base cover, and then adjust the distance between the equivalent test piece and the cover plate, that is, adjust the sealing gap, and the pressure and temperature in the chamber can be monitored in real time by the pressure sensor and the temperature sensor. The leakage amount can be measured from the opening in the middle of the base cover at the front end.

[0109] Leakage testing may include the following tests:

[0110] 1. The influence of static gap on leakage:

[0111] Study the effect of target clearance on leakage under different pressure ratios. The specific process is as follows:

[0112] Adjust the chamber pressure. After the pressure stabilizes, adjust the sealing gap to the target gap through the gap adjustment device and then take the leakage reading. Then, adjust the pressure to obtain the leakage Q. Next, change the target gap and test again. After all is completed, the leakage corresponding to different pressure ratios and different leakage amounts will be obtained. After all working conditions are completed, the leakage corresponding to each sealing gap and pressure ratio is counted.

[0113] 2. The influence of dynamic clearance on leakage:

[0114] The gap adjustment device is used to control the sealing gap to change according to the sine and cosine laws, and the leakage amount under dynamic gap is obtained.

[0115] As an improvement of the technical solution, Figure 3As shown, the gap adjustment device includes a servo motor 41, a coupling 42 and a ball screw 43, wherein the servo motor 41 is connected to the ball screw 43 through the coupling 42, and is used to drive the ball screw 43 to rotate, and the nut 44 installed on the ball screw 43 is fixedly connected to the rear end of the movable seat 3, and is used to drive the movable seat 3 to move axially along the ball screw 43.

[0116] As an improvement of the technical solution, Figure 3 As shown, a plurality of guide rails 11 are provided at intervals and in parallel on the inner wall of the base 1 , and the outer periphery of the movable seat 3 is connected to a slider 12 installed on the guide rails 11 .

[0117] As an improvement of the technical solution, Figure 3 As shown, the air supply device includes an air compressor 51, an air storage tank 52 and an air cylinder 53 connected in sequence. A flow meter 54 is provided on the pipeline between the air storage tank 52 and the air cylinder 53. Preferably, a cold dryer is also provided between the air storage tank 52 and the flow meter.

[0118] As an improvement of the technical solution, Figure 3 As shown, the test device for the influence of the full-circle straight-through grate sealing gap on the leakage volume also includes a displacement sensor 8 for detecting the distance between the equivalent test piece 10 and the cover plate 20. Preferably, the displacement sensor is an eddy current displacement sensor installed on the cover plate.

[0119] As an improvement of the technical solution, Figure 3 As shown, the test device for the influence of the full-circle straight-through comb tooth sealing gap on the leakage amount also includes a control system 9, which is connected to the gap adjustment device and the displacement sensor 8, and is used to control the gap adjustment device according to the distance detected by the displacement sensor 8, so as to achieve precise adjustment of the distance between the equivalent test piece 10 and the cover plate 20.

[0120] As an improvement of the technical solution, Figure 3 As shown, the control system 9 is also connected to the pressure sensor 6, the temperature sensor 7 and the gas supply device, and is used to collect the pressure and temperature collected by the pressure sensor 6 and the temperature sensor 7 in real time, and is also used to adjust the gas supply of the gas supply device according to the detection value of the pressure sensor 6, thereby realizing the regulation of the pressure in the chamber.

[0121] The detailed description of the present invention is written in a progressive manner, emphasizing the differences between the various implementation schemes, and similar parts thereof can be referenced to each other.

[0122] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. The test method for the effect of the full-circle straight-through grate tooth sealing gap on the leakage rate is characterized by: The steps include: Step 1: Design an equivalent test piece (10) of the full-circle straight-through type grate test piece (40), wherein the outer circumference of the full-circle straight-through type grate test piece (40) is provided with grate teeth at intervals, and the equivalent test piece (10) includes an annular body (101), and one side end face of the annular body (101) is provided with multiple ring teeth (102) at intervals from the inside to the outside, and the annular teeth (102) are coaxially arranged with the annular body (101), and the tooth shape, height, number of teeth and spacing between adjacent annular teeth of the annular teeth are consistent with the tooth shape, height, number of teeth and spacing between adjacent grate teeth on the full-circle straight-through type grate test piece (40), and the equivalent radius r1 of the innermost ring tooth of the annular teeth (102) is calculated by the following formula: Wherein, r1 is the equivalent radius of the innermost ring tooth of the annular tooth (102), that is, the distance between the inner side surface of the innermost ring tooth of the annular tooth (102) and the central axis of the annular body (101), z is the number of teeth of the grate teeth on the full-circle straight-through type grate teeth test piece (40), r is the radius of the full-circle straight-through type grate teeth test piece (40), and t is the tooth pitch of adjacent grate teeth on the full-circle straight-through type grate teeth test piece (40), wherein the tooth pitch refers to the distance between the same side surfaces of adjacent grate teeth; Step 2: Use the equivalent test piece (10) to replace the full-circle straight-through type comb tooth test piece (40), and use the cover plate (20) matched with the equivalent test piece (10) to replace the stator (30) matched with the full-circle straight-through type comb tooth test piece (40) to perform a leakage test. During the test, the distance between the equivalent test piece (10) and the cover plate (20) is equivalent to the distance between the full-circle straight-through type comb tooth test piece (40) and the stator (30). Adjusting the distance between the equivalent test piece (10) and the cover plate (20) is equivalent to adjusting the sealing gap between the full-circle straight-through type comb tooth test piece (40) and the stator (30).

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