Turbo mechanical seal inlet rotational flow generator
By designing the three-stage energy conversion of the reverse spiral cavity and the flow guide gate at the turbine mechanical seal inlet, the problem of insufficient fluid excitation and leakage regulation in traditional sealing technology is solved, the fluid excitation suppression and leakage flow reduction are achieved, and the circumferential flow regulation effect of the sealing fluid is improved.
Patent Information
- Application Number
- CN202510732336.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-03
- Publication Date
- 2025-07-18
AI Technical Summary
Traditional sealing technology has shortcomings in suppressing fluid excitation and leakage regulation in turbine machinery, especially the control effect of the resistive gate on leakage flow at the gap is poor, making it difficult to achieve effective reversal of circumferential flow.
A turbine mechanically sealed inlet cyclone generator is used to form a reverse rotation cavity between the stator and the rotor, and the three-stage energy conversion of "pressure energy → axial kinetic energy → reverse rotation kinetic energy" is achieved by using the tooth tip induction groove and the flow guide gate to achieve the three-stage energy conversion of "pressure energy → axial kinetic energy → reverse rotation kinetic energy" to enhance the import pre-rotation regulation effect.
Effectively suppress fluid vibration, reduce leakage flow, improve the vibration suppression performance of sealed fluid, and achieve effective reversal and regulation of circumferential flow.
Smart Images
Figure CN120331891A_ABST
Abstract
Description
[0001] The present invention relates to a swirl generator at the inlet of a turbomachinery seal, belonging to the field of sealing technology. Background Art
[0002] Seals are key components in various turbomachines such as aeroengines, gas turbines, steam turbines, compressors, and fans to inhibit the leakage of working media and improve the operating efficiency of the units. With the increase in the medium parameters and capacity of turbomachines, the problem of seal fluid-induced vibration becomes prominent, and advanced sealing technologies need to consider the performance of suppressing fluid-induced vibration.
[0003] The circumferential flow at the seal inlet is the main cause of inducing seal fluid-induced vibration. To suppress the inlet pre-rotation, jet anti-rotation and anti-rotation grids are usually used at present. Among them, jet anti-rotation forms a reverse swirl jet in the cavity by introducing an external high-pressure gas source, which can achieve the active control of circumferential flow. However, this method has defects such as a complex gas supply system, an increased leakage amount, and a reduced effective working medium. The anti-rotation grid suppresses the inlet pre-rotation by the passive block of the circumferential baffle. Although this method does not affect the seal leakage performance, the control effect on the leakage flow at the gap is poor, and it is difficult to effectively reverse the circumferential flow.
[0004] In view of the above technical bottlenecks, the present invention proposes a new type of inlet swirl generator based on the three-stage energy conversion of "pressure energy → axial kinetic energy → reverse swirl kinetic energy" to achieve the purpose of enhancing the control effect of inlet pre-rotation and improving the performance of suppressing seal fluid-induced vibration. Summary of the Invention
[0005] The purpose of the present invention is to provide a swirl generator at the inlet of a turbomachinery seal to solve the problems raised in the above background art.
[0006] The technical solution of the present invention is as follows: A swirl generator at the inlet of a turbomachinery seal forms a reverse swirl cavity between a stator and a rotor coaxially, and a guide grid is arranged in the reverse swirl cavity; The reverse swirl cavity is successively divided into a divergent section and a convergent section along the flow direction of the working medium; A tip-induced groove is arranged upstream of the reverse swirl cavity; the tip-induced groove is used to make the leakage flow enter the reverse swirl cavity at an inclined radial deflection angle and match the expanding extension direction of the divergent section of the reverse swirl cavity, so that the leakage flow directly impacts the surface of the guide grid.
[0007] Preferably, the reverse swirl cavity is mirror-symmetric in the axial direction.
[0008] Preferably, the ratio of the divergent section to the convergent section of the reverse swirl cavity in the axial direction is 1:1 - 2:1; the divergent section expands linearly, and the convergent section contracts linearly.
[0009] Preferably, a convex portion is provided on one side of the stator close to the rotor, and the reverse rotation cavity includes a rotor-side groove recessed in the rotor and a stator-side groove recessed in the convex portion.
[0010] Preferably, the tip induction groove is recessed in the side wall of the rotor.
[0011] Preferably, the tip induction groove extends from the upstream of the convex portion to connect with the rotor-side groove, and the side of the tip induction groove connecting with the rotor-side groove is inclined and arranged parallel to the extending direction of the gradually expanding section of the stator-side groove.
[0012] Preferably, the distance L between the upstream side wall of the tip induction groove and the upstream side wall of the convex portion, the distance S between the stator and the rotor, and the depth of the tip induction groove is H.
[0013] Preferably, there are multiple groups of the flow guiding grids, and the multiple groups of flow guiding grids are circumferentially and uniformly distributed on the stator side of the reverse rotation cavity.
[0014] Preferably, the blades of the flow guiding grid adopt a deflecting flow guiding structure, and its flow guiding angle is opposite to the rotation direction of the rotor.
[0015] The present invention has the following beneficial effects: The present invention proposes a novel inlet swirl generator based on the three-stage energy conversion of "pressure energy → axial kinetic energy → reverse rotation kinetic energy". First, under the throttling action of the tip induction groove, part of the pressure energy is converted into axial kinetic energy to form a tip leakage jet. Subsequently, under the flow guiding action of the tip induction groove, the direction of the leakage jet is locally deflected and injected into the reverse rotation cavity at a certain radial deflection angle. When the leakage jet enters the reverse rotation cavity, a vortex will be formed at the rotor-side groove, and this vortex generates a radial pushing action on the leakage jet, making it close to the stator-side groove. Subsequently, under the forced guidance of the flow guiding grid in the stator-side groove, the leakage jet is converted into a circumferential flow rotating in the reverse direction, completing the regulation process of the circumferential flow.
[0016] The present invention converts the pressure energy driving the leakage flow into the reverse rotation kinetic energy for regulating the circumferential flow, solves the problem of insufficient circumferential flow regulation ability of the traditional anti-rotation grid, and has important engineering application value. Brief Description of the Drawings
[0017] Figure 1 is the three-dimensional structure schematic diagram of the present invention; Figure 2 is the three-dimensional explosion diagram of the present invention; Figure 3 is the front sectional view of the present invention; Figure 4 is Figure 3 the partial enlarged view of Figure 5 is the circumferential flow distribution nephogram in the reverse rotation cavity when α = 0°; Figure 6 It is the contour map of the circumferential flow distribution in the counter-rotating cavity when α = 5°; Figure 7 It is the contour map of the circumferential flow distribution in the counter-rotating cavity when α = 10°.
[0018] The reference signs in the figure are represented as: 1. Tip-induced groove; 2. Counter-rotating cavity; 3. Guide vane; 4. Sealing section; 5. Stator; 6. Rotor; 7. Inlet; 8. Outlet; 51. Protrusion; 52. Stator-side groove; 61. Rotor-side groove. Detailed implementation mode
[0019] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0020] A swirl generator at the inlet of a turbomachinery seal is arranged at the inlet of the sealing section 4, as Figures 1-4 shown: It includes: a tip-induced groove 1, a counter-rotating cavity 2, a guide vane 3, a stator 5 and a rotor 6. The counter-rotating cavity 2 is jointly formed by the stator 5 and the rotor 6 coaxially, and an array of guide vanes 3 is uniformly arranged in the circumferential direction.
[0021] The axial direction in this article refers to the axis of the stator 5 and the rotor 6, and the circumferential direction refers to the direction around the axis of the stator 5 or the rotor 6. The working fluid flows from the inlet 7 to the outlet 8.
[0022] The tip-induced groove 1 is used to guide the leakage fluid to form a radially deflected jet; The counter-rotating cavity 2 is arranged downstream of the tip-induced groove 1 and is used to receive the jet after radial deflection; The guide vane 3 is fixedly arranged in the counter-rotating cavity 2 and is used to forcibly convert the radially deflected jet into a flow in the counter-rotating direction.
[0023] The outlet direction of the tip-induced groove 1 matches the inlet angle of the guide vane 3, so that the jet directly impacts the surface of the guide vane.
[0024] The blades of the guide vane 3 adopt a deflecting guide structure, and its guide angle is opposite to the rotation direction of the rotor; as Figure 2 shown, the guide vane 3 is arranged obliquely at 45° relative to the axial direction.
[0025] The counter-rotating cavity 2 has a gradually expanding - gradually contracting structure, and includes a gradually expanding section and a gradually contracting section with a mirror-symmetric structure along the flow direction (axial direction) of the working fluid. The ratio of the gradually expanding section to the gradually contracting section in the axial direction is 1:1 - 2:1; the gradually expanding section expands linearly, and the gradually contracting section contracts linearly; After the leakage jet enters the counter-rotating cavity 2, a vortex will be formed at the rotor-side groove, which exerts a pushing effect on the leakage jet, causing it to approach the stator-side groove, thereby strengthening the circumferential regulation effect of the guide grid 3 in the cavity. The counter-rotating cavity 2 provides space for the radial deflection of the jet direction and is also the main place where the flow direction undergoes counter-rotating deflection.
[0026] On the side of the stator 5 close to the rotor 6, a convex portion 51 is provided in a convex manner. The counter-rotating cavity 2 includes a rotor-side groove 61 recessed in the rotor 6 and a stator-side groove 52 recessed in the convex portion 51. There is a certain gap between the convex portion 51 and the rotor 6.
[0027] The tip-induced groove 1 is recessed in the side wall of the rotor 6 and is located upstream of the rotor-side groove 61. A throttling structure is provided at the inlet section of the tip-induced groove 1, and the fluid pressure energy is converted into kinetic energy through the narrowed throttling structure. As Figure 4 shown, the throttling structure includes that the tip-induced groove 1 extends from upstream of the convex portion 51 to connect with the rotor-side groove 61. The side of the tip-induced groove 1 connected to the rotor-side groove 61 is inclined and is arranged parallel to the extending direction of the gradually expanding section of the stator-side groove 52, α = 0°, and the distance between the inclined surface of the tip-induced groove 1 and the gradually expanding section of the stator-side groove 52 is very small; The distance L between the upstream side wall of the tip-induced groove 1 and the upstream side wall of the convex portion 51, the distance S between the stator 5 and the rotor 6, and the depth of the tip-induced groove 1 is H.
[0028] This generator is installed at the inlet of the sealing structure 4.
[0029] The application of the inlet swirl generator for a turbomachinery seal is used to suppress the fluid excitation phenomenon in the turbomachinery seal and reduce the leakage flow rate. The turbomachinery includes a steam turbine, a gas turbine, or a compressor.
[0030] Under the throttling effect of the tip-induced groove 1, part of the fluid pressure energy is converted into kinetic energy to form a tip leakage jet. At the same time, the unique flow guiding structure of the tip-induced groove 1 forces the leakage jet to generate a radial deflection, creating conditions for subsequent full contact with the guide grid 3. When the leakage flow enters the counter-rotating cavity 2 at a specific radial deflection angle, a vortex will be formed at the rotor-side groove of the counter-rotating cavity 2, which exerts a radial pushing effect on the leakage jet, causing it to cling to the stator-side groove of the counter-rotating cavity 2. Subsequently, under the forced guidance of the guide grid 3 in the stator-side groove, the leakage jet is converted into a counter-rotating circumferential flow, completing the regulation process of the circumferential flow. Finally, a circumferential swirl with a significant counter-rotating velocity component is formed at the outlet of the swirl generator, completing the regulation of the pre-swirl direction at the seal inlet.
[0031] Fluid-induced vibration suppression mechanism: The device is installed at the inlet of the sealing structure 4. After the leakage fluid flows through the device, a reverse circumferential velocity component is formed, reversing the pre-rotation direction at the sealing inlet, and suppressing the occurrence of fluid-induced vibration from the source.
[0032] Example 1: As Figure 5 shown, the circumferential flow distribution nephogram in the reverse swirl cavity obtained by using the computational fluid dynamics method when α = 0° (note: the rotation direction is the positive direction).
[0033] Operating parameters: inlet pressure 2 bar, outlet pressure 1 bar, rotational speed 3000 rpm.
[0034] Structural parameters: the ratio of the expansion section to the contraction section is 1:1; L / S = 0.15; H / S = 0.3.
[0035] It can be found that after the fluid enters the swirl generator, the circumferential flow presents a reverse swirl flow pattern.
[0036] Example 2: As Figure 6 shown, the inclined surface of the tooth tip induction groove 1 is not parallel to the expansion section of the stator side groove 52 and forms an angle. When the angle α = 5°, the circumferential flow distribution nephogram in the reverse swirl cavity obtained by using the computational fluid dynamics method, and the other conditions are the same as those in Example 1. It can be seen from Figure 6 this that its circumferential flow is relatively Figure 5 worse.
[0037] Example 3: As Figure 7 shown, the inclined surface of the tooth tip induction groove 1 is not parallel to the expansion section of the stator side groove 52 and forms an angle. When the angle α = 10°, the circumferential flow distribution nephogram in the reverse swirl cavity obtained by using the computational fluid dynamics method, and the other conditions are the same as those in Example 1. It can be seen from Figure 7 this that its circumferential flow is relatively Figure 6 worse.
[0038] According to Figures 5-7 it can be known that changing the angle α can adjust the incident angle of the swirl generator, affecting the circumferential flow regulation effect of the swirl generator. The larger the angle α, the lower the effect of the finally formed reverse circumferential velocity component; the influence of other conditions on the effect of the reverse circumferential velocity component is relatively smaller than that of the angle α.
[0039] The above are only the embodiments of the present invention, and do not limit the scope of the patent of the present invention accordingly. Any equivalent structure or equivalent process transformation made by using the content of the specification and drawings of the present invention, or directly or indirectly applied in other related technical fields, shall be included in the patent protection scope of the present invention by the same token.
Claims
1. A swirl generator at the inlet of a turbomachinery seal, an inverse swirl chamber (2) is formed between a stator (5) and a rotor (6) that are coaxial, and a guide vane grid (3) is arranged in the inverse swirl chamber (2). It is characterized in that: The inverse swirl chamber (2) is sequentially divided into a divergent section and a convergent section along the working fluid flow direction; A tip-induced groove (1) is arranged upstream of the inverse swirl chamber (2); the tip-induced groove (1) is used to make the leakage flow enter the inverse swirl chamber (2) at an inclined radial deflection angle, and match the expanding extension direction of the divergent section of the inverse swirl chamber (2), so that the leakage flow directly impacts the surface of the guide vane grid (3).
2. The inlet swirl generator of the turbomachinery seal according to claim 1, wherein: The inverse swirl chamber (2) has a mirror-symmetric structure axially.
3. The inlet swirl generator of the turbomachinery seal according to claim 2, wherein: The ratio of the lengths of the divergent section and the convergent section of the inverse swirl chamber (2) axially is 1:1 - 2:1; the divergent section expands linearly, the convergent section contracts linearly, the angle between the line of the divergent section and the axis is 30° - 45°, and the angle between the convergent section and the axis is 45° - 60°.
4. The inlet swirl generator of the turbomachinery seal according to claim 2, characterized in that: A raised portion (51) is arranged on the side of the stator (5) close to the rotor (6), and the inverse swirl chamber (2) includes a rotor-side groove (61) recessed in the rotor (6) and a stator-side groove (52) recessed in the raised portion (51).
5. The inlet swirl generator of the turbomachinery seal according to claim 4, characterized in that: The tip-induced groove (1) is recessed in the side wall of the rotor (6).
6. The inlet swirl generator of the turbomachinery seal according to claim 5, characterized in that: The tip-induced groove (1) extends from upstream of the raised portion (51) to connect with the rotor-side groove (61), and the side of the tip-induced groove (1) connecting with the rotor-side groove (61) is inclined and arranged parallel to the extending direction of the divergent section of the stator-side groove (52).
7. The inlet swirl generator of the turbomachinery seal according to claim 6, characterized in that: The distance L between the upstream side wall of the tip-induced groove (1) and the upstream side wall of the raised portion (51), the distance S between the stator (5) and the rotor (6), and the depth of the tip-induced groove (1) is H.
8. The inlet swirl generator of the turbomachinery seal according to claim 1, characterized in that: There are multiple groups of the guide vane grids (3), and multiple groups of the guide vane grids (3) are circumferentially and evenly distributed on the stator side of the inverse swirl chamber (2).
9. The inlet swirl generator of the turbomachinery seal according to claim 8, characterized in that: The blades of the guide vane grid (3) adopt a deflecting flow guiding structure, and its flow guiding angle is opposite to the rotation direction of the rotor (6).