Sealing device and method based on bifurcated confluence resistance increasing mechanism

Abstract

The invention provides a sealing device and method based on a bifurcated confluence resistance increasing mechanism. The sealing device comprises a backflow ring and a labyrinth ring. The backflow ring is a static assembly and is provided with multiple stages of backflow channels; the comb tooth ring is a rotating assembly and is provided with multiple stages of inclined comb teeth; according to the method, after high-pressure airflow enters the sealing device, the backflow channel guides bifurcated flow to form reverse jet flow, the reverse jet flow converges with forward airflow at the top ends of the comb teeth, and then local dissipation and flow resistance are improved. The invention provides a brand new sealing device which has higher sealing efficiency, and is simple in structure, high in reliability and wide in application range.

Description

Technical Field

[0001] The present invention belongs to the field of aeroengines and gas turbines, and in particular relates to a sealing device and method based on a bifurcated and converging flow resistance increasing mechanism. Background Art

[0002] Improving sealing efficiency is crucial to reducing air system gas consumption, preventing gas intrusion, and improving the efficiency of aircraft engines and gas turbines. Existing sealing devices mainly include: comb seals, brush seals, and fingertip seals. Among them, the comb seal is a non-contact seal with the advantages of simple structure and stable performance, but the sealing efficiency needs to be improved. Brush seals and fingertip seals are contact seals, which have high sealing efficiency, but complex structures and the risk of abrasion. In order to meet the needs of the next generation of aircraft engines and gas turbines, it is urgent to propose a non-contact, simple-structure, stable-performance, and higher-sealing efficiency sealing device. Summary of the invention

[0003] In order to solve the problems of the prior art, the present invention provides a sealing device and method based on a bifurcated and converging flow resistance increasing mechanism, which increases local dissipation and flow resistance by extracting the bifurcated flow and merging it with the mainstream step by step, thereby greatly improving the sealing efficiency.

[0004] The present invention provides a sealing device based on a bifurcated converging flow resistance increasing mechanism, which has a simple structure and comprises a reflux ring and a comb ring; the reflux ring and the comb ring are in an inner and outer circular ring relationship, and there is a gap between the reflux ring and the comb ring; the reflux ring is a stationary component; and the comb ring is a rotating component.

[0005] The reflux ring is provided with N-stage reflux channels, the channel width is d3, the channel inlet angle and outlet angle are α1 and α2 respectively, the channel inlet and outlet spacing is d1, and N is a natural number.

[0006] The grate ring is provided with N levels of grate teeth, the grate tooth inclination angle is β, the distance between adjacent grate teeth is d2, and the grate tooth gap is d4.

[0007] The number of the reflux channels is the same as the number of the comb teeth, and the outlet of the reflux channel is directly opposite to the top of the comb teeth; the width d3 of the reflux channel is smaller than the comb tooth gap d4; the inlet and outlet spacing d1 of the reflux channel is smaller than the adjacent comb tooth spacing d2, and the inlet of the reflux channel is far away from the outlet of the previous channel.

[0008] The inlet angle α1 of the reflux channel is greater than or equal to the outlet angle α2, and the inlet and outlet directions of the channel are toward the high-pressure inlet.

[0009] The comb teeth are inclined toward the high-pressure inlet.

[0010] In one embodiment of the present invention, the device is used in a centrifugal compressor, and the device also includes a stationary casing and an impeller;

[0011] The recirculation ring is connected to the stationary casing by bolts;

[0012] The comb ring is tightly connected to the adjacent rotating blade disk; the adjacent rotating blade disk refers to the impeller;

[0013] A chamber is formed between the recirculation ring, the comb ring and the stationary casing, and the recirculation ring and the stator casing are connected to each other via bolts.

[0014] In another embodiment of the present invention, the device is used in an axial flow turbine interstage, and the device also includes a front stage turbine blade disk, a stationary guide vane and a rear stage turbine blade disk;

[0015] The recirculation ring is connected to the stationary guide vane by bolts;

[0016] The grate ring is tightly connected to the adjacent rotating blade disk; the adjacent rotating blade disk refers to the front stage turbine blade disk and the rear stage turbine blade disk;

[0017] The stationary guide vanes and the preceding turbine blade disk form a chamber, which is a high-pressure chamber;

[0018] The stationary guide vanes and the rear-stage turbine blade disk form a chamber, which is a low-pressure chamber.

[0019] The present invention also provides a sealing method for a bifurcated converging flow resistance increasing mechanism, comprising the following steps:

[0020] Step 1, after the high-pressure airflow enters the device, the bifurcated flow is separated from the mainstream and enters the first-stage reflow channel, and after the bifurcated flow flows out of the first-stage reflow channel, it forms a reverse jet with a direction opposite to the mainstream and merges with the mainstream at the top of the corresponding comb teeth;

[0021] In step 2, the bifurcated flow is separated from the main flow and enters the second-stage reflux channel, and the process in step 1 is repeated.

[0022] The beneficial effects of the present invention are: 1. A new non-contact sealing device is proposed based on the bifurcation and confluence resistance-increasing mechanism; 2. The device has a simple structure, high reliability and long service life; 3. The sealing efficiency is higher. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 Schematic diagram of the sealing device based on the bifurcation and confluence resistance increase mechanism.

[0025] Figure 2 Schematic diagram of the sealing device based on the bifurcation and converging flow resistance increase mechanism in the centrifugal compressor.

[0026] Figure 3 Schematic diagram of the sealing device based on the bifurcated and converging flow resistance increase mechanism between axial flow turbine stages.

[0027] Figure 4 This is the velocity cloud diagram inside the comb tooth sealing device.

[0028] Figure 5 This is the velocity cloud diagram inside the sealing device based on the bifurcation and confluence resistance increase mechanism.

[0029] Figure 6 This is the velocity vector distribution diagram inside the comb tooth sealing device.

[0030] Figure 7 This is the velocity vector distribution diagram inside the sealing device based on the bifurcation and confluence resistance increase mechanism.

[0031] Figure 8 The pie chart shows the leaked traffic.

[0032] The numbers in the figure indicate the following: 1. recirculation ring; 2. comb ring; 3. stationary casing; 4. bolt; 5. front-stage turbine blade disk; 6. stationary guide vane; 7. rear-stage turbine blade disk; 11. recirculation channel; 21. comb teeth; 22. impeller. DETAILED DESCRIPTION

[0033] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0034] like Figure 1 The figure shows a sealing device based on the bifurcated and converging flow resistance increasing mechanism proposed in an embodiment of the present invention, comprising a reflux ring 1 , a comb ring 2 , a reflux channel 11 , and comb teeth 21 .

[0035] The recirculation ring 1 and the grate ring 2 are in an inner and outer ring relationship, and there is a gap of 0.2-0.5 mm between the recirculation ring 1 and the grate ring 2; the recirculation ring 1 is a stationary component, and the recirculation ring 1 is connected to the stationary casing or the stationary guide vane by bolts; the grate ring 2 is a rotating component, and the grate ring 2 is tightly connected to the adjacent rotating blade disk.

[0036] The reflux ring 1 is provided with a multi-stage reflux channel, the channel width is d3, the channel inlet and outlet angles are α1 and α2 respectively, and the channel inlet and outlet spacing is d1.

[0037] The grate ring 2 is provided with multi-stage grate teeth, the grate tooth inclination angle is β, the distance between adjacent grate teeth is d2, and the grate tooth gap is d4.

[0038] Furthermore, the number of the reflux channels is the same as the number of the comb teeth, and the channel outlets are directly opposite to the top ends of the comb teeth; the reflux channel width d3 needs to be smaller than the comb tooth gap d4; the reflux channel inlet and outlet spacing d1 needs to be smaller than the adjacent comb tooth spacing d2, and it should be ensured that the reflux channel inlet is away from the previous channel outlet; the reflux channel inlet inclination angle α1 shall not be smaller than the outlet inclination angle α2; the inclination directions of the reflux channel inlet and outlet and the comb teeth are both toward the high-pressure inlet and shall not be reversed.

[0039] The sealing device based on the bifurcated confluence resistance increasing mechanism proposed in the embodiment of the present invention can be applied to many scenarios, such as Figure 2 The figure shows a schematic diagram of a sealing device based on a bifurcated and converging flow resistance increasing mechanism in a centrifugal compressor. In this embodiment, the centrifugal compressor structure includes a return ring 1, a grate ring 2, a stationary casing 3, bolts 4, a return channel 11, grate teeth 21, and an impeller 22.

[0040] A chamber is formed between the recirculation ring 1, the comb ring 2 and the stationary casing. At this time, reducing the leakage flow of the chamber is beneficial to improving the efficiency of the centrifugal compressor.

[0041] The recirculation ring 2 and the stator casing 3 are connected to each other via bolts 4 .

[0042] like Figure 3 The figure shows a schematic diagram of a sealing device based on a bifurcated and convergent flow resistance increasing mechanism between axial flow turbine stages. In this embodiment, the axial flow turbine structure comprises a return ring 1, a grate ring 2, a front stage turbine blade disk 5, a stationary guide vane 6, a rear stage turbine blade disk 7, a return channel 11, and a grate 21.

[0043] The stationary guide vane 6 and the front-stage turbine blade disk 5 and the rear-stage turbine blade disk 7 respectively form a chamber, wherein the front-stage chamber is a high-pressure chamber and the rear-stage chamber is a low-pressure chamber.

[0044] The recirculation ring 1 and the grate ring 2 form a sealing device based on a bifurcated and converging flow resistance-increasing mechanism, thereby preventing inter-stage airflow leakage and improving turbine efficiency.

[0045] Furthermore, the application example illustrates the gain effect of the sealing device based on the bifurcated confluence resistance increase mechanism. In this embodiment, the reflux ring is provided with a 4-level reflux channel, the channel width d3 is 0.5mm, the channel inlet angle α1 and the outlet angle α2 are both 30°, and the channel inlet and outlet spacing d1 is 6mm; the comb ring is provided with 4 levels of comb teeth, the comb tooth inclination angle β is 45°, the adjacent comb tooth spacing d2 is 8mm, and the comb tooth gap d4 is 0.6mm. In addition, for comparison, the embodiment also includes a comb tooth sealing device without a reflux ring, and its comb tooth parameters are the same as those of the sealing device based on the bifurcated confluence resistance increase mechanism. The total inlet pressure of the sealing device is 202650, the total outlet pressure is 101325, and the corresponding pressure drop ratio is 2. The rotation speed of the comb ring is 9000rpm.

[0046] The above parameters are modeled and simulated to obtain Figure 4 Velocity cloud diagram inside the comb teeth sealing device, Figure 5 Velocity cloud diagram inside the sealing device based on the bifurcation and confluence resistance increase mechanism, Figure 6 Velocity vector distribution diagram in the comb tooth sealing device, Figure 7 Velocity vector distribution diagram in the sealing device based on the bifurcation and confluence resistance increase mechanism, where Figure 4 and Figure 5 Velocity refers to speed. In the traditional grate sealing device, the airflow flows step by step, the density decreases along the way, the speed increases accordingly, and a vortex is formed between the grate teeth. In the sealing device based on the bifurcated and converging resistance-increasing mechanism, the reflow channel separates the airflow and forms a reverse jet, which greatly reduces the maximum speed in the device, while the vortex between the grate teeth moves upward, and the mainstream flows close to the grate wall to the next level of grate teeth.

[0047] like Figure 8 The figure shows a leakage flow pie chart. Under the parameter conditions of this embodiment, the leakage flow of the comb-teeth sealing device is 0.194 kg / s, while the leakage flow of the sealing device based on the bifurcated confluence resistance-increasing mechanism is 0.159 kg / s. Compared with the comb-teeth sealing device, the efficiency of the sealing device based on the bifurcated confluence resistance-increasing mechanism is improved by 18.04%.

[0048] The present invention provides a sealing device and method based on a bifurcated confluence resistance-increasing mechanism. There are many methods and approaches to implement the technical solution. The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention. All components not specified in this embodiment can be implemented using existing technologies.

Claims

1. A sealing device based on bifurcated and converging flow resistance increasing mechanism, characterized in that: It comprises a reflux ring and a grate ring; the reflux ring and the grate ring are in an inner and outer ring relationship, and there is a gap between the reflux ring and the grate ring; the reflux ring is a stationary component; and the grate ring is a rotating component.

2. A sealing device based on bifurcated flow converging resistance increasing mechanism according to claim 1, characterized in that: The reflux ring is provided with N-stage reflux channels, the channel width is d3, the channel inlet angle and outlet angle are α1 and α2 respectively, the channel inlet and outlet spacing is d1, and N is a natural number.

3. A sealing device based on bifurcated and converging resistance-increasing mechanism according to claim 2, characterized in that: The grate ring is provided with N levels of grate teeth, the grate tooth inclination angle is β, the distance between adjacent grate teeth is d2, and the grate tooth gap is d4.

4. A sealing device based on bifurcated and converging flow resistance increasing mechanism according to claim 3, characterized in that: The number of the reflux channels is the same as the number of the comb teeth, and the outlet of the reflux channel is directly opposite to the top of the comb teeth; the width d3 of the reflux channel is smaller than the comb tooth gap d4; the inlet and outlet spacing d1 of the reflux channel is smaller than the adjacent comb tooth spacing d2, and the inlet of the reflux channel is far away from the outlet of the previous channel.

5. A sealing device based on bifurcated and converging resistance-increasing mechanism according to claim 4, characterized in that: The inlet angle α1 of the reflux channel is greater than or equal to the outlet angle α2, and the inlet and outlet directions of the channel are toward the high-pressure inlet.

6. A sealing device based on bifurcated and converging flow resistance increasing mechanism according to claim 5, characterized in that: The comb teeth are inclined toward the high-pressure inlet.

7. A sealing device based on bifurcated and converging flow resistance increasing mechanism according to claim 6, characterized in that: The device is used in a centrifugal compressor, and the device also includes a stationary casing and an impeller; The recirculation ring is connected to the stationary casing by bolts; The comb ring is tightly connected to the adjacent rotating blade disk; the adjacent rotating blade disk refers to the impeller; A chamber is formed between the recirculation ring, the comb ring and the stationary casing, and the recirculation ring and the stationary casing are connected to each other via bolts.

8. A sealing device based on bifurcated and converging flow resistance increasing mechanism according to claim 6, characterized in that: The device is used between stages of an axial flow turbine, and the device also includes a front-stage turbine blade disk, a stationary guide vane, and a rear-stage turbine blade disk; The recirculation ring is connected to the stationary guide vane by bolts; The grate ring is tightly connected to the adjacent rotating blade disk; the adjacent rotating blade disk refers to the front stage turbine blade disk and the rear stage turbine blade disk; The stationary guide vanes and the preceding turbine blade disk form a chamber, which is a high-pressure chamber; The stationary guide vanes and the rear-stage turbine blade disk form a chamber, which is a low-pressure chamber.

9. A sealing method for a bifurcated flow resistance increasing mechanism implemented by the device according to any one of claims 1 to 8, characterized in that: The steps include: Step 1, after the high-pressure airflow enters the device, the bifurcated flow is separated from the mainstream and enters the first-stage reflow channel, and after the bifurcated flow flows out of the first-stage reflow channel, it forms a reverse jet with a direction opposite to the mainstream and merges with the mainstream at the top of the corresponding comb teeth; Step 2: The bifurcated flow is separated from the main flow and enters the second-stage reflux channel, and the process in step 1 is repeated.

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