Test system and test method for sealing labyrinth under non-uniform gap condition

Abstract

The invention belongs to the technical field of aero-engine performance analysis, and particularly relates to a sealing labyrinth test system and a sealing labyrinth test method under a non-uniform gap condition. The device is characterized by comprising a test piece and a corresponding driving device, the driving device comprises a direct-current power supply, a high-pressure air source, a driver and a motor, the high-pressure air source is generated through a compressor and enters a shunt row through a filter, a pressure reducing valve and an electromagnetic valve, the shunt row is divided into multiple branches which are connected to an air inlet of the test piece through a pipe, and the driver is connected with the motor. An air outlet of the test piece is connected with a flow meter through a busbar, and the leakage flow of the labyrinth gap is measured through the flow meter; the driver is connected with the console and the motor, the console is connected with the electromagnetic valve, and the motor is connected with a rotating shaft of the test piece through the coupler; the test piece comprises a rotor structure and a stator structure which are connected through a bearing. The research on the labyrinth flow mechanism and the sealing rule under the non-uniform gap condition and the analysis on the thermosetting coupling of the air system and the component flow are realized.

Description

Technical Field

[0001] This invention belongs to the field of aero-engine performance analysis technology, specifically relating to a sealing tooth test system and test method under non-uniform gap conditions. Background Technology

[0002] Sealing elements are widely used in aero-engines, and the main factor affecting their sealing performance is the internal flow mechanism. In conventional air system analysis and design, a uniform clearance assumption is typically used. Taking a grate as an example, it is usually assumed that the distance between each grate and the sealing ring is the same. This is a reasonable assumption under steady-state conditions, but it is difficult to maintain this assumption throughout the transient process. This is because the main factors affecting the grate clearance are the deformation of the rotor and stator. The main factors affecting rotor deformation are the centrifugal force caused by rotation and the rotor temperature distribution, while the main factors affecting stator deformation are the pressure differential and the stator temperature distribution. Among these, temperature distribution is the most likely factor to cause non-uniform grate clearance. During the transient process of an aero-engine, the temperature evolution of the rotor and stator is very complex, with extreme cases such as cooling gas heating components and heating gas cooling components. This leads to very complex deformation patterns of the grate and sealing ring at the rotor tip, often resulting in non-uniform clearance. Compared to the case of uniform clearance, the flow mechanism of non-uniform clearance is more complex, affecting the throttling and sealing effect of the grate.

[0003] Therefore, under fluid-thermal coupling, especially fluid-thermal-solid coupling, without understanding the flow mechanism and sealing characteristics of the grating under non-uniform gap conditions, it is impossible to conduct analysis of the fluid-thermal coupling between the air system and components. This invention conducts experiments on the variable gap uniformity of typical grating interfaces, measures the flow parameters of the grating under non-uniform gap conditions, observes the flow phenomena in the grating under different gap non-uniformities, and understands the flow mechanism and sealing characteristics of the grating under non-uniform gap conditions. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art by providing a test system and method for sealing grates under non-uniform gap conditions. By changing the position of the bushing in the test system, different degrees of eccentricity are achieved, thereby obtaining different degrees of non-uniform gaps in the grates, realizing the "pre-settable, measurable, and comparable" non-uniform gap field for sealing grates.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is a test system for sealing grates under non-uniform gap conditions, comprising a test piece and a corresponding driving device, wherein the driving device comprises a DC power supply, a high-pressure air source generated by a compressor, a driver, and a motor; High-pressure gas enters the distributor in sequence through a filter, a pressure reducing valve, and a solenoid valve. The distributor has multiple gas supply branches, which are connected to the air inlet of the test piece through pipes. The air outlet of the test piece is connected to a flow meter through a manifold, thereby measuring the leakage flow rate between the grates. The aforementioned driver is connected to the control console and the motor respectively. The control console is connected to the solenoid valve, and the motor is connected to the shaft of the test piece via a coupling. The test piece includes a rotating shaft, and a rotor structure and a stator structure connected by bearings.

[0006] Furthermore, the stator structure includes a cavity shell, with a right cover plate and a left cover plate connected to both sides of the cavity shell via flanges. A right bushing and a left bushing are also provided inside the cavity shell. A right bearing seat is provided on the right cover plate, and a right bearing cover is installed on the right bearing seat. A left bearing seat is provided on the left cover plate, and a left bearing cover is installed on the left bearing seat. The right bushing and right bearing housing are fixedly connected to the right cover plate, the left bushing and left bearing housing are fixedly connected to the left cover plate, the right cover plate is fixedly installed on the right cavity seat, and the left cover plate is fixedly installed on the left cavity seat.

[0007] Furthermore, the rotor structure includes a main shaft, on which a right grate disc and a left grate disc are mounted. The right and left grate discs are circumferentially positioned to the main shaft via semi-circular keys, and axially positioned to the main shaft via hexagonal fastening bolts. The main shaft is mounted on the right and left bearing seats of the stator structure via angular contact bearings. The right and left grate discs are correspondingly arranged inside the right and left bushings of the stator structure, and an annular gap is formed between the right and left grate discs and the inner surfaces of the right and left bushings as a gas flow channel.

[0008] Furthermore, the right bushing is coaxially mounted with the cavity shell and the right cover plate, the left cover plate is coaxially mounted with the cavity shell, and the left bushing is not coaxially mounted with the left cover plate, thus achieving an eccentricity between the left bushing and the left cover plate. This results in a non-uniform annular gap between the left grate disc and the inner surface of the left bushing after installation. The right grate disc is coaxially mounted with the main shaft, and the left grate disc is eccentrically mounted with the main shaft. The eccentricity between the left grate disc and the main shaft is not greater than the average gap between the left grate disc and the left bushing. This achieves a periodic or locally varying non-uniform gap effect for the left grate disc during rotation.

[0009] Furthermore, the eccentricity value is not greater than the average gap between the left grate disc and the left bushing; the eccentricity value is achieved by setting a metal filler in the annular cavity between the left bushing and the cavity shell. The metal filler is an arc-shaped component made of an alloy with a low coefficient of thermal expansion. The metal filler is uniformly set in at least two along the circumference of the annular cavity between the left bushing and the cavity shell. The manufacturing dimensional tolerance of the contact surface between the metal filler and the cavity shell, as well as the contact surface between the metal filler and the right and left bushings, is not greater than ±0.01mm.

[0010] Furthermore, the inner wall of the left bushing is provided with at least three square groove structures along the circumference. Displacement sensors are installed in the square groove structures by fastening screws to realize the radial clearance measurement between the left bushing and the toothed disc at different circumferential positions. A pressure sensor is provided on the inner wall of the left bushing corresponding to the square groove structure to realize the pressure change measurement between the left bushing and the toothed disc at different circumferential positions. The present invention also provides a method for testing the tightness of a toothed comb under non-uniform gap conditions, as described above, comprising the following steps: Step 1: Assemble the rotor structure. Connect the left and right grate discs to the main shaft using a semi-circular key to achieve circumferential positioning, and fix them with hexagonal fastening bolts for axial positioning. The eccentricity value of the left grate disc should be consistent with the experimentally achieved eccentricity value, and should be less than the average grate gap to avoid scratching. After the rotor structure is assembled, dynamic balancing verification is required, and the imbalance should not exceed 1mm / s. Step 2: Install the bearing in the left bearing housing and install the left bearing cover on the left bearing housing to fix the bearing. Connect and fix the left bearing housing to the left cover plate and connect the left cover plate to the cavity shell. The bearing, left bearing cover, left cover plate and cavity shell of the stator structure are coaxially installed. The stator structure lies on the ground with the left cover plate as the bottom. Step 3: Install the pressure sensor and displacement sensor in the left bushing, place the left bushing in the stator structure, then install the rotor structure in the bearing, place the metal filler in the left bushing and cavity shell, measure the circumferential clearance, adjust the radial thickness of the metal filler to achieve the target clearance, and tighten the mating parts in the stator structure. Step 4: Install the bearing in the right bearing housing and install the right bearing cover on the right bearing housing to fix the bearing. Connect and fix the right bearing housing to the right cover plate and connect the right cover plate to the cavity shell. At the same time, install the right bushing on the right cover plate. Then connect the right cover plate to the cavity shell and install the left and right cavity seats to realize the installation of the test piece. Step 5: Connect the test piece and the corresponding drive device, and perform an airtightness test to prevent measurement errors caused by leakage; Step six: Conduct test measurements. First, the compressor provides pressurized airflow. The inlet pressure is adjusted by the inlet flow regulating valve of the non-uniform gap sealing tooth test system to control the inlet flow rate. Then, adjust the bypass regulating valve at the inlet of the experimental platform to fine-tune the flow rate so that the pressure at the inlet of the experimental platform meets the experimental requirements; after the inlet pressure stabilizes, read the pressure readings at each measuring point, and record the flow rate and inlet / outlet temperature parameters of the flow meter. Finally, adjust the current frequency to change the speed. After the speed stabilizes, repeatedly measure and record the pressure readings at each measuring point, as well as the flow rate and inlet / outlet temperature parameters of the flow meter. When adjusting the motor speed, adjust it gradually from low to high to prevent damage to the motor. After measuring the data at the highest speed, turn off the motor to complete the test.

[0011] The beneficial effects of this invention are as follows: This invention provides a sealing tooth test system and testing method under non-uniform gap conditions. Through an adjustable tooth rotor and bushing assembly, it realizes the flexible construction of non-uniform gap fields, which can reproduce the non-uniform distribution in steady state and respond to the instantaneous gap changes under dynamic working conditions. It can effectively simulate static and dynamic non-uniform phenomena, and has high-precision control capability and highly controllable gap morphology. Thus, it can grasp the flow mechanism and sealing law of tooth under non-uniform gap conditions, and carry out the analysis of the air system and component flow-thermal-structure coupling. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the overall testing system principle of the present invention; Figure 2 This is a schematic diagram of the overall test system structure of the present invention; Figure 3 This is a schematic diagram of the stator structure of the present invention; Figure 4 This is a schematic diagram of the rotor structure of the present invention; Figure 5 This is a schematic diagram of the bushing adjustment of the present invention; Figure 6 This is a schematic diagram showing the sensor installation location of the present invention.

[0013] In the diagram, 1. Rotor structure; 2. Stator structure; 3. Cavity shell; 4. Right bushing; 5. Left bushing; 6. Right cover plate; 7. Left cover plate; 8. Right bearing housing; 9. Left bearing housing; 10. Right bearing cover; 11. Left bearing cover; 12. Right cavity seat; 13. Left cavity seat; 14. Main shaft; 15. Right grate disc; 16. Left grate disc; 17. Hexagonal fastening bolt; 18. Angular contact bearing; 19. Metal filler; 20. Bushing fastening bolt; 21. Displacement sensor; 22. Pressure sensor. Detailed Implementation

[0014] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0015] To achieve the above objectives, the present invention provides the following specific embodiments: Figure 1 and 2 As shown, the sealing element test system under non-uniform gap conditions is characterized by including a test piece and a corresponding driving device. The driving device includes a DC power supply, a high-pressure air source, a driver, and a motor. The high-pressure air source is generated by a compressor and enters a flow divider through a filter, a pressure reducing valve, and a solenoid valve. The flow divider is divided into multiple branches and connected to the air inlet of the test piece through pipes. The air outlet of the test piece is connected to a flow meter through a manifold. The flow meter measures the leakage flow rate of the grate gap. The driver is connected to a control console and a motor. The control console is connected to a solenoid valve. The motor is connected to the rotating shaft of the test piece through a coupling. The test piece includes a rotor structure 1 and a stator structure 2 connected by bearings.

[0016] like Figure 3 As shown, the stator structure 2 includes a cavity shell 3. A right cover plate 6 and a left cover plate 7 are connected to both sides of the cavity shell 3 via flanges. A right bushing 4 and a left bushing 5 are also provided inside the cavity shell 3. A right bearing seat 8 is provided on the right cover plate 6, and a right bearing cover 10 is installed on the right bearing seat 8. A left bearing seat 9 is provided on the left cover plate 7, and a left bearing cover 11 is installed on the left bearing seat 9. The right bushing 4 and the right bearing seat 8 are fixedly connected to the right cover plate 6, and the left bushing 5 and the left bearing seat 9 are fixedly connected to the left cover plate 7. The right cover plate 6 is fixedly installed on the right cavity seat 12, and the left cover plate 7 is fixedly installed on the left cavity seat 13. The stator structure 2 provides support, sealing, lubrication, and a safe operating environment for the rotor structure 1.

[0017] like Figure 4 As shown, the rotor structure 1 includes a main shaft 14, on which a right grate disk 15 and a left grate disk 16 are mounted. The right grate disk 15 and the left grate disk 16 are circumferentially positioned with the main shaft 14 by a semi-circular key, and axially positioned with the main shaft 14 by hexagonal fastening bolts 17. The main shaft 14 is mounted on the right bearing seat 8 and the left bearing seat 9 of the stator structure 2 by angular contact bearings 18. The right grate disk 15 and the left grate disk 16 are correspondingly arranged in the right bushing 4 and the left bushing 5 of the stator structure 2. An annular gap is formed between the right grate disk 15 and the left grate disk 16 and the inner surface of the right bushing 4 and the left bushing 5 as a gas flow channel.

[0018] like Figure 5As shown, the right bushing 4 is coaxially installed with the cavity shell 3 and the right cover plate 6, the left cover plate 7 is coaxially installed with the cavity shell 3, and the left bushing 5 is not coaxially installed with the left cover plate 7, so that there is an eccentric value between the left bushing 5 and the left cover plate 7, thereby making the annular gap formed between the inner surface of the left toothed disc 16 and the left bushing 5 after installation non-uniform.

[0019] Furthermore, the eccentricity value is not greater than the average gap between the left grate disc 16 and the left bushing 5; the eccentricity value is achieved by setting a metal filler 19 and a bushing fastening bolt 20 in the annular cavity between the left bushing 5 and the cavity shell 3. The metal filler 19 is an arc-shaped component made of an alloy with a low coefficient of thermal expansion. The metal filler 19 is uniformly set in at least two along the circumference of the annular cavity between the left bushing 5 and the cavity shell 3. The manufacturing dimensional tolerance of the contact surface between the metal filler 19 and the cavity shell 3, as well as the contact surface between the metal filler 19 and the right bushing 4 and the left bushing 5, is not greater than ±0.01mm.

[0020] Furthermore, the right grate disk 15 is coaxially arranged with the main shaft 14, and the left grate disk 16 is eccentrically arranged with the main shaft 14. The eccentricity between the left grate disk 16 and the main shaft 14 is not greater than the average gap between the left grate disk 16 and the left bushing 5; thus realizing the periodic or locally varying non-uniform gap effect formed by the left grate disk 16 during rotation.

[0021] like Figure 6 As shown, further, the inner wall surface of the left bushing 5 is provided with at least three square groove structures along the circumference. A displacement sensor 21 is installed in the square groove structure by fastening screws to realize the radial gap measurement between the left bushing and the toothed disc at different circumferential positions. A pressure sensor 22 is provided on the inner wall of the left bushing 5 corresponding to the square groove structure to realize the pressure change measurement between the left bushing and the toothed disc at different circumferential positions.

[0022] A test method for sealing ferrules under non-uniform gap conditions, characterized by the following steps: Step 1: Assemble rotor structure 1. Connect the left grate plate 16 and the right grate plate 15 to the main shaft 14 via a semi-circular key to achieve circumferential positioning, and fix them with hexagonal fastening bolts 17 for axial positioning. The eccentricity value of the left grate plate 16 should be consistent with the experimentally achieved eccentricity value, and should be less than the average grate gap to avoid scratching. After the rotor structure 1 is assembled, dynamic balancing verification is required, and its imbalance should not exceed 1 mm / s. Step 2: Install the bearing in the left bearing housing 9 and install the left bearing cover 11 on the left bearing housing 9 to fix the bearing. Connect and fix the left bearing housing 9 to the left cover plate 7, and connect the left cover plate 7 to the cavity shell 3. The bearing, left bearing cover 9, left cover plate 7 and cavity shell 3 of the stator structure 2 are coaxially installed. The stator structure 2 lies on the ground with the left cover plate 7 as the bottom. Step 3: Install pressure sensor 22 and displacement sensor 21 in left bushing 4, and place left bushing 4 in stator structure 2. Then install rotor structure 1 in bearing, place metal filler 19 in left bushing 5 and cavity shell 3, measure circumferential clearance, adjust radial thickness of metal filler 19 to achieve target clearance, and tighten mating parts in stator structure 2. Step four: Install the bearing in the right bearing housing 8, and install the right bearing cover 10 on the right bearing housing 8 to fix the bearing. Connect and fix the right bearing housing 8 to the right cover plate 6, and connect the right cover plate 6 to the cavity shell 3. At the same time, install the right bushing 4 on the right cover plate 6. Then connect the right cover plate 6 to the cavity shell 3, and install the left and right cavity seats to realize the installation of the test piece. Step 5: Connect the test piece and the corresponding drive device, and perform an airtightness test to prevent measurement errors caused by leakage; Step six involves conducting experimental measurements. First, a pressurized airflow is supplied by the compressor. The inlet pressure is adjusted by regulating the inlet flow rate of the non-uniform gap sealing tooth test system, controlling the inlet flow rate. Then, the inlet flow bypass regulating valve of the test bench is adjusted to fine-tune the flow rate, ensuring the pressure at the inlet of the test bench meets the experimental requirements. Next, after the inlet pressure stabilizes, pressure readings are taken at each measuring point, and the flow meter flow rate and inlet / outlet temperature parameters are recorded. Finally, the current frequency is adjusted to change the rotational speed. After the speed stabilizes, the pressure readings at each measuring point are repeatedly measured, and the flow meter flow rate and inlet / outlet temperature parameters are recorded. When adjusting the motor speed, it should be gradually increased from low to high to prevent motor damage. After measuring the data at the highest speed, the motor is turned off.

[0023] The aforementioned sealing tooth test system and method under non-uniform gap conditions allows for the adjustment of the tooth disc and bushing to simulate different non-uniform gaps. When the bushing assembly is a perfect circle and coaxial with the bearing centerline, changing the eccentricity of the tooth disc enables dynamic simulation of non-uniform gaps, meaning that the gap at the same measuring point changes over time at the same rotational speed. When the tooth disc is concentric with the bearing centerline, changing the eccentricity and shape of the bushing enables static simulation of non-uniform gaps, meaning that the gap at the same measuring point remains essentially constant at the same rotational speed, but the measured values ​​at different circumferential positions are inconsistent. Furthermore, the test piece also supports a combination of eccentric bushing and eccentric tooth disc to simulate non-uniform gaps.

[0024] The aforementioned test system and method for sealing ferrules under non-uniform gap conditions ensures the control of the non-uniform gap through the following two parts: (1) Gap measurement: It consists of a circumferential indexing plate and a high-precision plug gauge. The circumferential indexing plate is coaxially mounted with the main shaft and uses a circumferentially evenly distributed method, with no less than 6 measuring points arranged around the circumference of the tooth. The plug gauge is a thin-plate structure with a measuring range of 0.05-3.00 mm, a resolution of 0.01 mm, and a measuring surface hardness ≥ HRC60 to ensure measurement accuracy in high-temperature (≤300℃) experimental environments.

[0025] The following steps are used to achieve quantifiable eccentricity control and construct a non-uniform gap field with a preset shape: Concentric reference state calibration: Insert metal fillers of the same thickness into the four circumferential positioning holes of the bushing (i.e., , (The thickness of the filler) The bushing is fixed by fastening bolts so that the bushing is completely aligned with the rotation center of the comb rotor. At this time, the gap value of each measuring point is detected by the measuring module. If the gap difference between each point is ≤0.02mm, it is determined to be a concentric reference state (uniform gap field). The average gap at this time is recorded as the reference benchmark for subsequent experiments.

[0026] Target eccentricity calculation and filler selection: Based on the non-uniform gap shape required for the experiment, the eccentricity e (unit: mm) of the bushing relative to the rotor is preset. The eccentricity e and the difference in filler thickness at the four positioning holes satisfy a strict geometric relationship: .

[0027] in: The thickness of the filler at the 0° and 180° positioning holes are respectively. The thickness of the filler at the 90° and 270° positioning holes are respectively.

[0028] Based on the above formula, calculate the required filler thickness in each direction and select the corresponding thickness from the standard filler library (tolerance ±0.01mm).

[0029] (2) Construction of non-uniform gap field: Remove the filler in the concentric reference state, install the selected metal filler in the 4 positioning holes according to the calculation results, and apply a preload (50-100N) evenly through the fastening bolts to fix the bushing in the preset eccentric position. At this time, the bushing and the rotation center of the rotor generate an eccentricity e, and a non-uniform gap field with e as the characteristic parameter is formed between the tooth and the bushing (the circumferential gap increases along the eccentric direction and decreases in the opposite direction).

[0030] The non-uniform gap characterization method adopts the approach of "multi-point measurement + quantitative index" to systematically describe the distribution characteristics of non-uniform gaps; (1) Circumferential multi-point measurement: Using the circumferential indexing plate for positioning, measure the gap between the tooth and the bushing at n equally divided points along the circumference of the tooth using a feeler gauge. (i=1,2,…n), each measuring point is measured 3 times, and the arithmetic mean is taken as the final gap value of that point to reduce the influence of random error.

[0031] (2) Quantitative parameter calculation: The data processing unit automatically calculates the following core parameters based on the measurement data: Average gap: Reflects the overall size of the gap, and the calculation formula is:

[0032] Maximum clearance difference: Reflects the fluctuation range of circumferential clearance, and is calculated using the following formula:

[0033] Gap non-uniformity: This comprehensively characterizes the degree of non-uniformity in the gap, and the calculation formula is as follows: .

[0034] The experimental steps are as follows: Initial clearance setting: During the static assembly stage, insert calibrated 304 stainless steel filler sheets (thickness 0.10-0.50mm, configured in 0.05mm gradients) into the specified quadrant; lock the bushing flange; after removing the filler, use a three-coordinate plug gauge system to collect the initial clearance of each circumferential interval. Repeat the test three times at each measuring point to eliminate the influence of assembly stress.

[0035] Dynamic testing phase: Data from a capacitive displacement sensor was acquired within the 0-8 kHz speed range (sampling rate 5 kHz, sensitivity 2 μm); the real-time gap δ(t,θ) was synthesized from the initial value and the dynamic increment. .

[0036] The system of this invention also has broad versatility and good scalability, and is applicable to various comb tooth structures such as straight teeth, helical teeth, and stepped teeth. By replacing the corresponding comb tooth rotor assembly and bushing assembly, users can simulate non-uniform gap fields in different sealing structures, providing an experimental basis for the study of comb tooth sealing performance in various engineering scenarios.

[0037] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A test system for sealing ferrules under non-uniform gap conditions, characterized in that, It includes a test piece and a corresponding drive device, which includes a DC power supply, a high-pressure air source generated by a compressor, a driver, and a motor. High-pressure gas enters the distributor in sequence through a filter, a pressure reducing valve, and a solenoid valve. The distributor has multiple gas supply branches, which are connected to the air inlet of the test piece through pipes. The air outlet of the test piece is connected to a flow meter through a manifold, thereby measuring the leakage flow rate between the grates. The aforementioned driver is connected to the control console and the motor respectively. The control console is connected to the solenoid valve, and the motor is connected to the shaft of the test piece via a coupling. The test piece includes a rotating shaft, and a rotor structure and a stator structure connected by bearings.

2. The sealing test system for ferrules under non-uniform gap conditions as described in claim 1, characterized in that, The stator structure includes a cavity shell, with a right cover plate and a left cover plate connected to both sides of the cavity shell via flanges. A right bushing and a left bushing are also provided inside the cavity shell. A right bearing seat is provided on the right cover plate, and a right bearing cover is installed on the right bearing seat. A left bearing seat is provided on the left cover plate, and a left bearing cover is installed on the left bearing seat. The right bushing and right bearing housing are fixedly connected to the right cover plate, the left bushing and left bearing housing are fixedly connected to the left cover plate, the right cover plate is fixedly installed on the right cavity seat, and the left cover plate is fixedly installed on the left cavity seat.

3. The sealing test system for ferrules under non-uniform gap conditions as described in claim 1, characterized in that, The rotor structure includes a main shaft, on which a right grate disc and a left grate disc are mounted. The right and left grate discs are circumferentially positioned to the main shaft via semi-circular keys, and axially positioned to the main shaft via hexagonal fastening bolts. The main shaft is mounted on the right and left bearing seats of the stator structure via angular contact bearings. The right and left grate discs are correspondingly arranged inside the right and left bushings of the stator structure, and an annular gap is formed between the right and left grate discs and the inner surfaces of the right and left bushings as a gas flow channel.

4. A test system for sealing ferrules under non-uniform gap conditions as described in claim 2 or 3, characterized in that, The right bushing is coaxially mounted with the cavity shell and the right cover plate, the left cover plate is coaxially mounted with the cavity shell, and the left bushing is not coaxially mounted with the left cover plate, so that there is an eccentric value between the left bushing and the left cover plate, thereby making the annular gap formed between the inner surface of the left grate plate and the left bushing after installation non-uniform; the right grate plate is coaxially mounted with the main shaft, and the left grate plate is eccentrically mounted with the main shaft, the eccentric value between the left grate plate and the main shaft is not greater than the average gap between the left grate plate and the left bushing; thus, the left grate plate forms a non-uniform gap effect with periodic or local variations during rotation.

5. The sealing test system for ferrules under non-uniform gap conditions as described in claim 4, characterized in that, The eccentricity value is not greater than the average gap between the left grate and the left bushing. The eccentricity value is achieved by setting a metal filler in the annular cavity between the left bushing and the cavity shell. The metal filler is an arc-shaped component made of an alloy with a low coefficient of thermal expansion. The metal filler is uniformly set in at least two along the circumference of the annular cavity between the left bushing and the cavity shell. The manufacturing dimensional tolerance of the contact surface between the metal filler and the cavity shell, as well as the contact surface between the metal filler and the right and left bushings, is not greater than ±0.01mm.

6. A test system for sealing ferrules under non-uniform gap conditions as described in claim 2 or 3, characterized in that, The inner wall of the left bushing is provided with at least three square groove structures along the circumference. Displacement sensors are installed in the square groove structures by fastening screws to realize the radial clearance measurement between the left bushing and the grate plate at different circumferential positions. Pressure sensors are provided on the inner wall of the left bushing corresponding to the square groove structures to realize the pressure change measurement between the left bushing and the grate plate at different circumferential positions.

7. A method for testing the tightness of a toothed comb under non-uniform gap conditions, as described in claims 1-6, characterized in that... Includes the following steps: Step 1: Assemble the rotor structure. Connect the left and right grate discs to the main shaft using a semi-circular key to achieve circumferential positioning, and fix them with hexagonal fastening bolts for axial positioning. The eccentricity value of the left grate disc should be consistent with the experimentally achieved eccentricity value, and should be less than the average grate gap to avoid scratching. After the rotor structure is assembled, dynamic balancing verification is required, and the imbalance should not exceed 1mm / s. Step 2: Install the bearing in the left bearing housing and install the left bearing cover on the left bearing housing to fix the bearing. Connect and fix the left bearing housing to the left cover plate and connect the left cover plate to the cavity shell. The bearing, left bearing cover, left cover plate and cavity shell of the stator structure are coaxially installed. The stator structure lies on the ground with the left cover plate as the bottom. Step 3: Install the pressure sensor and displacement sensor in the left bushing, place the left bushing in the stator structure, then install the rotor structure in the bearing, place the metal filler in the left bushing and cavity shell, measure the circumferential clearance, adjust the radial thickness of the metal filler to achieve the target clearance, and tighten the mating parts in the stator structure. Step 4: Install the bearing in the right bearing housing and install the right bearing cover on the right bearing housing to fix the bearing. Connect and fix the right bearing housing to the right cover plate and connect the right cover plate to the cavity shell. At the same time, install the right bushing on the right cover plate. Then connect the right cover plate to the cavity shell and install the left and right cavity seats to realize the installation of the test piece. Step 5: Connect the test piece and the corresponding drive device, and perform an airtightness test to prevent measurement errors caused by leakage; Step six: Conduct test measurements. First, the compressor provides pressurized airflow. The inlet pressure is adjusted by the inlet flow regulating valve of the non-uniform gap sealing tooth test system to control the inlet flow rate. Then, adjust the bypass regulating valve at the inlet of the experimental platform to fine-tune the flow rate so that the pressure at the inlet of the experimental platform meets the experimental requirements; after the inlet pressure stabilizes, read the pressure readings at each measuring point, and record the flow rate and inlet / outlet temperature parameters of the flow meter. Finally, adjust the current frequency to change the speed. After the speed stabilizes, repeatedly measure and record the pressure readings at each measuring point, as well as the flow rate and inlet / outlet temperature parameters of the flow meter. When adjusting the motor speed, adjust it gradually from low to high to prevent damage to the motor. After measuring the data at the highest speed, turn off the motor to complete the test.

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