A high pre-rotation intake experimental device and experimental method for brush seal

Abstract

The application discloses a high pre-rotation intake experimental device for brush seal and an experimental method, and particularly relates to the field of rotary mechanical seal. The device comprises an intake chamber, a support chamber and an outlet chamber, and the intake chamber is provided with an air inlet; one end of a rotating shaft extends into the intake chamber and is connected with a rotor; an annular cyclone plate is arranged on the inner side wall of the intake chamber, a plurality of inclined through channels are evenly and sequentially arranged on the cyclone plate in the circumferential direction, and the distance from the inlet and outlet of the through channels to the center of the cyclone plate is the same; the through channels are communicated with the air inlet; a plurality of suction holes are evenly arranged on the side wall of the support chamber in the circumferential direction, and each suction hole is communicated with an exhaust mechanism; a brush seal ring is connected to the inner wall of the support chamber, and the inlet of the suction hole is located between the brush filament bundle of the brush seal ring and the outlet of the through channel. Based on the device, the flow characteristics of high cyclone working conditions can be simulated.

Description

Technical Field

[0001] This application relates to the field of rotary mechanical seals, and more particularly to a high pre-rotation intake experimental apparatus and method for brush seals. Background Technology

[0002] Brush seals, due to their excellent sealing performance, high-temperature resistance, and low leakage characteristics, have been widely used in high-speed rotating machinery such as aero engines, gas turbines, and steam turbines. In the extreme operating environments of engines, brush seals must withstand complex conditions such as high pressure differentials, high temperatures, and high inlet swirl. For example, in certain applications, such as the external sealing position of a turbine blade pre-swirl air supply system, the upstream inflow often has extremely high circumferential velocity; simultaneously, the rotor linear velocity sensed by the brush tips is even higher.

[0003] Under such a high inlet vortex, the brush filament bundle is highly susceptible to significant deformation and circumferential instability. Large circumferential deformation can cause the brush filament tips to fly radially away from the rotor surface, significantly increasing the sealing gap and causing a substantial increase in leakage. This not only leads to a sharp decline in sealing performance but also shortens the seal's service life. This failure risk is particularly pronounced under high speed and high pressure differential conditions.

[0004] To address this issue, conducting experimental research on the deformation and instability mechanism of brush filaments under high swirling conditions is of great significance. However, under current experimental conditions, a key bottleneck exists—it is difficult to reliably generate high-intensity swirling airflow comparable to real-world operating conditions upstream of the brush seal. This is mainly due to the fact that the flow resistance of the brush filament bundle itself is significantly greater than that of conventional swirling generation devices such as swirling orifice plates, resulting in a substantial reduction in the pressure differential of the swirling orifice plates, which in turn limits the formation of swirling velocity. Existing conventional air intake methods (such as direct-flow intake or low-angle swirling intake) can only generate relatively low circumferential velocities, making it difficult to simulate the flow characteristics under high swirling conditions. Summary of the Invention

[0005] The main objective of this application is to provide a high-pre-swirl inlet experimental device and method for brush seals, aiming to solve the problem that existing experimental devices are difficult to simulate the flow characteristics of high-swirl conditions.

[0006] To achieve this objective, this application provides a high pre-swirl inlet experimental device for brush seals, comprising: a base, on which an inlet casing, a support casing, and an outlet casing are sequentially arranged along the inlet direction; an airflow inlet is provided on the inlet casing; a rotating shaft, one end of which extends into the inlet casing and is connected to a rotor, the rotor being located within the support casing and the outlet casing, forming a first gap with both; an annular swirl plate is provided on the inner wall of the inlet casing, and multiple inclined through channels are evenly and sequentially opened along the circumference on the swirl plate, the inlet of the through channels, The distance from the outlet to the center of the swirl plate is the same; the through channel is connected to the airflow inlet; the end faces of the intake casing and the rotor are sealed by a seal, and a second gap is formed between the seal and the support casing. The second gap is connected to the through channel and the first gap respectively; multiple suction holes are evenly opened on the side wall of the support casing along the circumference, and each suction hole is connected to an exhaust mechanism; the inlet of the suction hole is located at the second gap; a brush-type sealing ring is connected to the inner wall of the support casing, and the brush filament bundle of the brush-type sealing ring is located in the first gap and contacts the rotor.

[0007] Optionally, the venting mechanism includes a suction pipe, one end of which is connected to a suction hole, and the other end is connected to a receiving tank via a suction tube, with an venting valve installed on the receiving tank.

[0008] Optionally, a positioning groove adapted to the swirl plate is provided on the inner end face of the intake casing. The positioning groove is connected to the airflow inlet, and the swirl plate is located in the positioning groove.

[0009] Optionally, the number of through channels is 12-96, and the total area of ​​all through channels accounts for 15%-45% of the area of ​​the swirl plate.

[0010] Optionally, a speed sensor is provided on the inner wall of the support casing, and the speed sensor is located between the inlet of the suction hole and the bristle bundle.

[0011] Optionally, the outlet end of the air outlet casing is connected to a flow meter via a pipe.

[0012] Optionally, the flow meter is a thermal mass flow meter.

[0013] Optionally, the seal is a toothed grate.

[0014] To achieve this objective, this application also provides a high pre-swirl inlet test method for brush seals, employing a high pre-swirl inlet test apparatus, and the method includes:

[0015] The airflow passes through the air inlet of the intake casing, and enters the second pore through the through-pass.

[0016] The airflow in the second pore is divided into two paths: one path enters the exhaust mechanism through the suction hole, and the other path flows to the bristle bundle.

[0017] By adjusting the pressure at the outlet of the suction hole through the exhaust mechanism, the speed of the airflow entering the first pore is controlled, thereby achieving high swirling air intake for the brush seal.

[0018] Compared with the prior art, the beneficial effects of this application are as follows:

[0019] The high pre-swirl inlet experimental device for brush seals of the present invention includes a swirl plate with an inclined through-channel between the airflow inlet and the brush filament bundle, and a suction hole on the support casing with a corresponding exhaust mechanism. This allows the airflow to gain initial rotational momentum and accelerate as it enters the through-channel. Subsequently, the airflow passes through the suction hole, causing a portion of the airflow to be actively drawn away, thereby creating a pressure difference upstream of the brush filament bundle. This pressure difference significantly increases both the axial and tangential velocities of the remaining airflow, further enhancing the swirl intensity. Simultaneously, the exhaust flow rate is adjusted by the exhaust mechanism, thereby regulating the swirl velocity upstream of the brush filament bundle. By combining the suction hole with the through-channel on the swirl plate, a high-intensity swirl can be generated upstream of the brush seal, simulating the flow characteristics under high swirl conditions. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of the structure of a high pre-swirl intake experimental device for brush seals according to this application;

[0021] Figure 2 This is a cross-sectional view of a high pre-rotation intake experimental apparatus for brush seals according to this application;

[0022] Figure 3 This is a partial structural schematic diagram of a high pre-swirl intake experimental device for brush seals according to this application;

[0023] Figure 4 This is a flow field diagram of a high pre-swirl intake experimental device for brush seals according to this application;

[0024] Figure 5 This is a schematic diagram of the swirl plate in a high pre-swirl inlet experimental device for brush seals according to this application;

[0025] Figure 6 for Figure 5 A magnified view of a portion of the image;

[0026] Figure 7 To compare the distribution of swirling velocity under the operating conditions of Simulation Experiment 1;

[0027] Figure 8 To compare the distribution of swirling velocity under the operating conditions of Simulation Experiment 2;

[0028] Figure 9 This is a diagram showing the distribution of swirl velocity under one working condition of a high pre-swirl intake experimental device for brush seals according to this application.

[0029] Figure 10 This diagram shows the distribution of swirl velocity under another operating condition of the high pre-swirl inlet experimental device for brush seals according to this application.

[0030] In the diagram, 1. Base, 101. Support platform, 102. Support, 2. Shaft, 3. Inlet casing, 4. Support casing, 5. Outlet casing, 6. Airflow inlet, 7. Rotor, 8. Swirl plate, 9. Through channel, 10. Seal, 11. Suction hole, 12. Exhaust mechanism, 121. Suction pipe, 122. Suction tube, 123. Container tank, 124. Exhaust valve, 13. Brush seal ring, 14. Positioning groove, 15. Speed ​​sensor, 16. Probe casing.

[0031] The realization of the purpose, functional features and advantages of this application will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0032] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0033] The first embodiment of the present invention provides a high pre-swirl inlet experimental apparatus for brush seals, such as... Figure 1-3 As shown, the device includes a base 1 and a rotating shaft 2. An intake casing 3, a support casing 4, and an exhaust casing 5 are sequentially arranged on the base 1 along the air intake direction. An airflow inlet 6 is provided on the intake casing 3. One end of the rotating shaft 2 extends into the intake casing 3 and is connected to a rotor 7. The rotor 7 is located within the support casing 4 and the exhaust casing 5, forming a first gap between them. An annular swirl plate 8 is provided on the inner wall of the intake casing 3, and multiple inclined through channels 9 are evenly and sequentially formed along the circumference on the swirl plate 8. Figure 5As shown, the distances from the inlet and outlet of the through-channel 9 to the center of the swirl plate 8 are the same; the through-channel 9 is connected to the airflow inlet 6; the end faces of the intake casing 3 and the rotor 7 are sealed by a seal 10, forming a second gap between the seal 10 and the support casing 4, which is connected to the through-channel 9 and the first gap respectively; multiple suction holes 11 are evenly opened on the side wall of the support casing 4 along the circumference, and each suction hole 11 is connected to an exhaust mechanism 12; the inlet of the suction hole 11 is located at the second gap; a brush-type sealing ring 13 is connected to the inner wall of the support casing 4, and the brush filament bundle of the brush-type sealing ring 13 is located in the first gap and contacts the rotor 7. A positioning groove 14 adapted to the swirl plate 8 is opened on the inner end face of the intake casing 3, the positioning groove 14 is connected to the airflow inlet 6, and the swirl plate 8 is located in the positioning groove 14. The seal 10 is a comb, and the tooth surface of the comb contacts the rotor 7.

[0034] In this embodiment, an air intake channel is formed by connecting the second gap between the seal 10 and the support casing 4, and the first gap between the rotor 7 and the support casing 4 and the exhaust casing 5. Airflow enters the through-channel 9 from the airflow inlet 6, gains initial rotational momentum, and accelerates. It then enters the second gap, where it is divided into two paths by the suction hole 11: the first path continues axially towards the brush filament bundle and enters the downstream area through the first gap; the second path enters the exhaust mechanism 12 through the suction hole 11 and is discharged to the atmosphere. The presence of the suction hole 11 actively draws away some airflow, creating a pressure difference upstream of the brush filament bundle. This pressure difference significantly increases both the axial and tangential velocities of the remaining airflow, further enhancing the swirling intensity. Simultaneously, the exhaust flow rate adjusted by the exhaust mechanism 12 regulates the swirling speed upstream of the brush filament bundle. By combining the suction hole 11 with the through-channel 9 on the swirl plate 8, a high-intensity swirling flow can be generated upstream of the brush seal, simulating the sealing performance under real-world conditions.

[0035] To ensure the stability of the intake casing 3, the support casing 4, and the exhaust casing 5, the base 1 in this embodiment includes a support platform 101, on which a support 102 is provided, and the exhaust casing 5 is fixed on the support 102; the support casing 4 is fixedly connected to the intake casing 3 and the exhaust casing 5 respectively.

[0036] For example, the number of through channels 9 is 12-96, and the total area of ​​all through channels 9 accounts for 15%-45% of the area of ​​the swirl plate 8. The through channels 9 can be cylindrical straight holes, constriction holes, blade-shaped slots, leaf-shaped holes, or compound angle spray holes (axial + tangential double inclination: the hole axis simultaneously has an axial inclination angle and a tangential offset angle, forming a spiral jet). The swirl plate 8 can be a multi-layered staggered orifice plate (double or triple layers), formed by stacking two or three layers of thin plates. The holes in each layer of thin plates are staggered in the circumferential direction of the swirl plate 8 at different angles, but the holes are the same in the radial direction of the swirl plate 8. The surface of the swirl plate 8 is polished to reduce flow resistance and improve the energy utilization efficiency of the airflow.

[0037] In this embodiment, the function of the swirl plate 8 is to guide the airflow into the brush filament bundle and generate a pre-swirl effect by changing the direction of the airflow. The shape, aperture, and tilt angle of the through channel 9 on the swirl plate 8 are adjustable to control the rotation intensity and flow rate of the airflow. Specifically, when the swirl plate 8 includes multiple layers of staggered perforated plates, the perforated plates can be designed with graduated rotating locking rings to achieve adjustable shape, aperture, and tilt angle; or, replaceable perforated cores (straight perforated core, constricted perforated core, blade perforated core) can be used at the same perforation position to achieve rapid switching of angle and perforation type by replacement.

[0038] Furthermore, the venting mechanism 12 includes a suction pipe 121, one end of which is connected to a suction port 11, and the other end is connected to a receiving tank 123 via a suction pipe 122. An venting valve 124 is installed on the receiving tank 123. The venting valve 124 can be an electric valve, which can adjust the outlet pressure of the suction port 11, thereby controlling the airflow through the suction port 11 and thus adjusting the swirl velocity upstream of the brush seal. This method allows for the observation of brush filament deformation under different swirl velocities in experiments, enabling the study of the sealing performance and deformation characteristics of the brush seal under different swirl intensities. In experiments requiring high swirl velocities, the suction port 11 can be connected using a suction pump, for example, by installing a suction pump within the suction pipe 121, thereby generating a higher pressure differential and achieving a higher swirl velocity. The suction pump provides a wider range of swirl adjustment, allowing experiments to cover a wider range of operating conditions and adapting to brush seal performance testing under high swirl conditions.

[0039] Furthermore, a speed sensor 15 is installed on the inner wall of the support casing 4, located between the inlet of the suction port 11 and the brush filament bundle. For example, the speed sensor 15 can be a five-hole probe, which is connected to the support casing 4 via a probe casing 16. Specifically, a positioning hole is formed on the side wall of the support casing 4, positioning the probe casing 16 within the positioning hole, thereby placing the five-hole probe between the inlet of the suction port 11 and the brush filament bundle. The outlet end of the exhaust casing 5 is connected to a flow meter via a pipe. For example, the flow meter is a thermal mass flow meter.

[0040] In this embodiment, the velocity sensor 15 measures the swirling velocity of the airflow passing through the brush filament bundle in real time, which can accurately obtain airflow velocity data under different swirling conditions; at the same time, the flow meter measures the leakage amount under different swirling velocities, thereby enabling the testing and recording of the sealing performance of the brush seal under different swirling velocity conditions and evaluating the impact of swirling velocity on the sealing leakage performance.

[0041] The second embodiment of the present invention provides a high pre-swirl inlet test method for brush seals, and the high pre-swirl inlet test apparatus specifically includes the following steps:

[0042] like Figure 4 As shown, the airflow enters the second pore through the air inlet 6 (inlet flow area) of the intake casing 3, passes through the through channel 9 (swirling plate 8 flow area), and then enters the second pore. The airflow in the second pore splits into two paths: one path enters the exhaust mechanism 12 through the suction port 11 (suction flow area), and the other path flows from the first pore (upstream flow area of ​​the brush seal) to the brush seal ring 13 (brush filament flow area) and enters the downstream flow area of ​​the brush seal. The exhaust mechanism 12 adjusts the pressure at the outlet of the suction port 11 to control the speed of the airflow entering the first pore, achieving high-swirling airflow intake for the brush seal. During the experiment, the pressure at the outlet of the suction port 11 can be adjusted within the range of 0.1 MPa to 0.4 MPa.

[0043] Example

[0044] To verify the performance of the method of the present invention under different suction conditions, geometric extraction and parametric modeling were performed on the flow domain containing the swirl-generating components (including the swirl plate 8, suction hole 11, and brush sealing ring 13) in the high pre-swirl inlet experiment. Mesh generation was completed, and CFD numerical calculations were carried out. (Calculation domain illustration) Figure 4 The computational domain is modeled using circumferential periodic symmetry, with a unit angle of 18°. A full rotation around the axis restores the entire circumferential flow channel (corresponding to 20 equally divided periods). The suction holes 11 have a diameter of 8mm, and there are 48 suction holes 11 in total. The pressure downstream of the brush bundle is set to 0.1MPa, and a high-pressure suction pump is used for suction. The distance between the swirl plate 8 and the brush-type sealing ring 13 is 20mm. Figure 5-6As shown, the thickness of the swirl plate 8 is 16 mm. Thirty-six inclined through-channels 9 (i.e., cylindrical straight holes) are evenly distributed circumferentially on the swirl plate 8. The area between the inlet and outlet of the through-channels 9 is a contraction zone. The cross-sectional shape of the through-channels 9 is circular, and the angle between the axis and radial direction of each hole is 75°. The hole diameter is 8 mm or 15 mm. Comparative simulation experiments were conducted, including Comparative Simulation Experiment 1 (excluding the suction hole 11 and the brush-type sealing ring 13) and Comparative Simulation Experiment 2 (excluding the brush-type sealing ring 13). The circumferential velocity at the "swirling section" location was measured using a five-hole probe, and the average area of ​​the circumferential velocity at the swirling section was calculated, i.e., the swirling velocity upstream of the brush filament bundle. The results are shown in Table 1.

[0045] Table 1 Experimental Results

[0046]

[0047] Table 1 shows the experimental results of the comparative simulation experiment 1. The high pre-swirl inlet experimental device only includes swirl plate 8, and the diameter of the through channel 9 is 8mm. No brush seal or suction structure is added. The ability of swirl plate 8 to generate swirl is evaluated by analyzing its flow characteristics. Figure 7 The figure shows the distribution of swirling velocity under this operating condition. As can be seen from the figure, the average swirling velocity of the swirling plate 8 reaches 358 m / s, while the highest swirling velocity is close to 400 m / s. This indicates that the swirling plate 8 has an excellent ability to generate swirling flow, and it can produce a relatively strong and efficient swirling flow field.

[0048] Table 2 shows the experimental results of the comparative simulation experiment 2. The high pre-swirl intake experimental device includes a swirl plate 8 and a brush seal. The diameter of the through channel 9 is 8mm, and no suction structure is added. Figure 8 The swirling velocity distribution under this structure is shown. (Combined with Table 1 and...) Figure 8 The results show that adding the brush-type sealing ring 13 downstream of the swirl plate 8 significantly reduces the swirling velocity, with the average swirling velocity dropping to 23 m / s and the highest swirling velocity reaching only 26 m / s. Compared to the structure with only the swirl plate 8, the swirling velocity is significantly reduced, even approaching zero swirling. This phenomenon is caused by the blocking effect of the brush-type sealing ring 13, which causes the airflow to backflow after passing through the swirl plate 8 region and entering the upstream region of the brush bundle, significantly reducing the gas velocity and thus offsetting the swirling effect of the swirl plate 8. Therefore, this structure is not suitable for experimental conditions under swirling conditions.

[0049] The data in items 3-7 of the table represent the test results of the high pre-swirl intake experimental device of the invention. The diameter of the through-channel 9 in the high pre-swirl intake experimental device corresponding to items 3-6 in the table is 8mm. From the data in items 3-6 of the table, it can be seen that the high pre-swirl intake experimental device of the present invention can adjust the upstream swirl velocity of the brush filament bundle by adjusting the suction pressure, i.e., the pressure at the outlet of the suction hole 11; and as the pressure difference between the inlet pressure of the intake casing 3 and the outlet pressure of the suction hole 11 increases, the upstream swirl velocity of the brush filament bundle increases. Furthermore, Figure 9 The table shows the swirl velocity distribution under condition number 4, compared to... Figure 8 , Figure 9 The addition of suction orifice 11 significantly increased the swirling velocity, with an average swirling velocity approaching 127 m / s and a maximum swirling velocity reaching 220 m / s. This is because the introduction of suction orifice 11 allows some airflow to flow out from the upstream of the brush bundle, eliminating the original blockage effect and thus increasing the swirling velocity. The suction orifice 11 reduces airflow resistance by minimizing airflow stagnation in the recirculation region, thereby optimizing the airflow rotation characteristics. As the swirling velocity increases, the flow field of the entire structure more closely resembles the experimental requirements, demonstrating superior swirling generation capability.

[0050] The data in serial number 7 of the table refers to the high pre-swirl intake experimental device of the present invention, and the diameter of the through channel 9 is 15 mm. Figure 10 The swirling velocity distribution under this structure is shown. (Compared to...) Figure 9 compared to, Figure 10 The results show that after increasing the diameter of the suction hole 11, the average swirling velocity increased to 228 m / s, and the highest swirling velocity reached 329 m / s, which significantly improved the swirling intensity and met the swirling velocity requirements under all experimental conditions.

[0051] The above are merely preferred embodiments of this application and do not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. A high pre-swirl inlet experimental apparatus for brush seals, characterized by, The application relates to a high pre-rotation air inlet experimental device and a method thereof. The base is provided with an air inlet casing, a support casing and an air outlet casing in sequence along an air inlet direction; the air inlet casing is provided with an air inlet; A rotating shaft is arranged in the air inlet casing and connected with a rotor; the rotor is arranged in the support casing and the air outlet casing and forms first interspaces with the two casings; An annular cyclone plate is arranged on the inner wall of the air inlet casing; a plurality of inclined through channels are evenly arranged on the cyclone plate in a circumferential direction; the inlet and the outlet of the through channels are located at the same distance from the center of the cyclone plate; the through channels are communicated with the air inlet; The end surface between the air inlet casing and the rotor is sealed by a sealing element; the sealing element and the support casing form a second interspace; the second interspace is communicated with the through channels and the first interspaces; A plurality of suction holes are evenly arranged on the side wall of the support casing in a circumferential direction; each suction hole is communicated with an exhaust mechanism; the inlet of the suction hole is located at the second interspace; A brush seal ring is connected to the inner wall of the support casing; the brush filaments of the brush seal ring are located in the first interspace and are in contact with the rotor.

2. The high pre-whirl inlet experimental apparatus for brush seal according to claim 1, wherein, The exhaust mechanism comprises a suction pipeline; one end of the suction pipeline is connected with the suction hole; the other end of the suction pipeline is connected with a containing tank through a suction pipe; the containing tank is provided with an exhaust valve.

3. The high pre-swirl inlet test device for brush seals of claim 1, wherein, A positioning groove matched with the cyclone plate is arranged on the inner end surface of the air inlet casing; the positioning groove is communicated with the air inlet; the cyclone plate is located in the positioning groove.

4. The high pre-swirl inlet test apparatus for brush seals of claim 1, wherein, The number of the through channels is 12-96; the total area of all the through channels accounts for 15%-45% of the area of the cyclone plate.

5. The high pre-swirl inlet test apparatus for brush seals of claim 1, wherein, A speed sensor is arranged on the inner wall of the support casing; the speed sensor is located between the inlet of the suction hole and the brush filaments.

6. The high pre-swirl inlet test apparatus for brush seals of claim 1, wherein, The air outlet end of the air outlet casing is connected with a flow meter through a pipeline.

7. The high pre-swirl inlet test apparatus for brush seals of claim 6, wherein, The flow meter is a thermal mass flow meter.

8. The high pre-swirl inlet test apparatus for brush seals of claim 1, wherein, The sealing element is a grid.

9. A method for high pre-rotation inlet experiment for brush seal, characterized in that, The application discloses a high pre-rotation air inlet experimental device and a method thereof. Air flows into the second interspace through the air inlet of the air inlet casing and the through channels; The air in the second interspace is divided into two paths; one path of air flows into the exhaust mechanism through the suction hole; the other path of air flows to the brush filaments; The pressure of the outlet of the suction hole is adjusted through the exhaust mechanism; the speed of the air flowing into the first interspace is controlled; and high-rotation air inlet of the brush seal is realized.

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