Novel turbomachinery vector sealing structure

Abstract

The utility model discloses a novel turbomachinery vector sealing structure. A vector sealing cavity is formed between a stator shell containing sealing teeth and a rotor. The vector sealing cavity is of a spray pipe type structure in mirror symmetry, and the spray pipe type structure comprises multiple stages of sealing cavities which are sequentially connected end to end and are provided with double throat parts; the sealing cavity is sequentially divided into an expansion section and a contraction section in the airflow flowing direction, and a tooth tip jet flow bypass is arranged between the contraction section and the throat part adjacent to the downstream of the contraction section; according to the thrust vectoring nozzle, the sealing cavity is designed to be of a thrust vectoring nozzle structure with a bypass channel, by means of tooth cavity pressure difference generated by the throttling effect, bypass jet flow is spontaneously driven to be mixed with main leakage flow, a leakage path is guided to directionally deflect in the circumferential direction and the radial direction, multi-dimensional reconstruction of a sealing flow field is achieved, and the dual purposes of reducing leakage and restraining fluid excitation are achieved. And a new method is provided for reducing sealing leakage and improving the excitation suppression performance of sealing fluid.

Description

TECHNICAL FIELD

[0001] The utility model relates to a sealing structure technical field, concretely is a novel turbine machinery vector sealing structure. BACKGROUND

[0002] Sealing is the key component of various turbine machinery such as aero-engine, gas turbine, steam turbine, compressor and fan to inhibit leakage of working medium and improve operation efficiency of the unit. However, with the continuous improvement of turbine medium parameters, the fluid excitation problem caused by sealing is increasingly prominent.

[0003] The further development of advanced sealing technology needs to consider the leakage and fluid excitation performance. Various configuration improvement schemes are usually proposed on the basis of traditional labyrinth seal in the prior art; such as boss seal, staggered tooth seal and high-low tooth seal, etc. For example, the patent announcement No. CN212407573U discloses "a staggered type oblique-tooth labyrinth seal structure", the sealing teeth are inclined in the opposite direction of the flow direction, the adjacent sealing teeth come from the rotating part steam seal body and the stationary part steam seal body, and are staggered arranged.

[0004] Although this type of labyrinth seal effectively improves the leakage performance, its stability is poor and easy to cause fluid excitation problem.

[0005] Or try to process texture (such as honeycomb, pass, scallop, etc.) on the sealing surface, divide the traditional circumferential through sealing cavity into independent chambers to enhance the gap damping effect, such as the patent publication No. CN110513154A discloses "a pocket type damping seal structure with chamber in circumferential divergent type", the stator, sealing teeth and circumferential baffle, wherein the stator is divided into a plurality of alternately arranged basic chambers and secondary chambers by the sealing teeth along the axial direction, the circumferential baffle is a plurality of, penetrates the basic chamber and the secondary chamber and is arranged along the circumferential direction of each chamber to form a plurality of pocket type chambers, the distance from the upper top surface of each pocket type chamber to the center axis of the stator increases uniformly along the rotation direction of the rotor, forming a circumferentially divergent wedge-shaped gap structure.

[0006] Although the fluid excitation problem is alleviated to some extent, however, the leakage performance of this method is greatly affected by the matching of texture structure and gap size, and it is difficult to improve the comprehensive performance

[0007] Or from the perspective of flow field regulation, anti-rotation flow technology represented by resistance grid and jet resistance is proposed, such as the patent announcement No. CN113606344B discloses "a labyrinth seal based on tooth gap anti-rotation plate to optimize the dynamic characteristics of the rotor", a plurality of anti-rotation plate structures are arranged on the sealing stator wall surface between the sealing teeth, each anti-rotation plate structure is uniformly distributed along the circumferential direction and is deflected to the reverse rotation direction on the meridian plane, so that the airflow passing through the anti-rotation plate structure is guided to the downstream in the reverse rotation direction. At the same time, the sealing gap of the upstream sealing teeth and / or the downstream sealing teeth adjacent to the anti-rotation plate structure can be changed, so as to expand the radial height of the jet flow between the teeth;

[0008] Although significant progress has been made in suppressing fluid excitation, such technologies often ignore the performance of leakage, and the leakage suppression effect is even worse than that of traditional labyrinth seals.

[0009] The above prior art proposes various improvement schemes from the aspects of configuration improvement and flow field regulation, and certain progress has been made, but it is still impossible to realize the synergistic improvement of "leakage reduction" and "vibration suppression" performance. Practical new type

[0010] The purpose of the present utility model is to provide a novel turbomachinery vector seal structure to solve the problems in the above background art.

[0011] To achieve the above purpose, the present utility model provides the following technical scheme:

[0012] A novel turbomachinery vector seal structure, a vector seal cavity formed between the stator shell containing sealing teeth and the rotor;

[0013] The vector seal cavity is a mirror-symmetrical nozzle structure, and the nozzle structure includes a plurality of sealing cavities connected in sequence and having double throats.

[0014] The sealing cavity is divided into an expansion section and a contraction section in sequence along the airflow direction, and a tooth tip jet bypass is arranged between the contraction section and the throat adjacent to the downstream thereof.

[0015] Preferably, the tooth tip jet bypass is arranged on the stator shell containing sealing teeth.

[0016] Preferably, the outlet of the tooth tip jet bypass has a plurality of groups arranged uniformly along the circumferential direction of the rotor axis.

[0017] Preferably, the extension directions of the outlets of the plurality of groups of tooth tip jet bypasses are located in the same plane and are perpendicular to the axial direction of the nozzle structure.

[0018] Preferably, the outlet direction of the tooth tip jet bypass forms a jet inclination angle of 30°-60° with the rotor in the plane.

[0019] Preferably, the inlet of the tooth tip jet bypass extends linearly inward along the center axis of the sealing cavity from the middle of the converging section.

[0020] Preferably, the inlet of the tooth tip jet bypass is arranged in a circle around the rotor axis.

[0021] Preferably, the ratio of the expansion section to the converging section along the center axis of the sealing cavity is 2:1-3:1.

[0022] Preferably, the expansion section linearly expands, and the converging section linearly shrinks.

[0023] Preferably, the expansion angle of the expansion section is 10°-90°, and the convergence angle of the converging section is 90°-170°.

[0024] Compared with the prior art, the utility model has the beneficial effects that:

[0025] The utility model discloses a sealing cavity is designed as the vector jet pipe structure with bypass channel, utilizes the pressure difference of the tooth cavity generated by throttling effect, and the bypass jet is mixed with the main leakage flow, and the leakage path is guided to deflect in the circumferential direction and radial direction, multi-dimensional reconstruction of the sealing flow field is realized, and the dual purpose of reducing leakage and inhibiting fluid excitation is achieved.

[0026] The utility model discloses a mirror image symmetry's double throat part vector jet pipe type sealing cavity structure provides radial - circumferential compound deflection's geometric space for leakage flow, arranges inverse rotation induction jet groove at each stage sealing tooth tip, utilizes tooth tip jet induction leakage flow to occur radial - circumferential compound deflection in sealing cavity, and the curved torsional flow form in the cavity induced by tooth tip jet induction can prolong the leakage path, strengthen the turbulent energy dissipation in the cavity, increase the flow resistance in the cavity. Meanwhile, tooth tip jet forms " air curtain barrier " at each stage sealing cavity entrance, effectively improves the local flow resistance of tooth tip, can further strengthen the leakage suppression effect. The vector sealing belongs to the tooth cavity cooperative resistance enhancement scheme, and its leakage suppression performance will be superior to the scheme based on the resistance enhancement of sealing cavity or sealing tooth.

[0027] Tooth tip jet injects sealing cavity in the inverse rotation direction, and the circumferential flow is offsetted / turned over through momentum, and the generation of fluid excitation is inhibited from the source. Compared with the traditional counter-rotation flow technology, the vector sealing scheme has two advantages: first, the whole flow field is regulated through the series connection of multiple sealing cavities, breaking through the limitation of traditional local jet regulation; second, the counter-rotation jet intensity is automatically adjusted with the sealing pressure difference, forming self-adaptive matching for high parameter working conditions. The above two points ensure the effectiveness of the vector sealing " vibration suppression " and the robustness in a wide working condition range. BRIEF DESCRIPTION OF DRAWINGS

[0028] In order to more clearly illustrate the technical scheme of the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the description of the embodiments, obviously, the drawings described in the following description are only some embodiments of the present application, and for the ordinary skilled in the art, other drawings can also be obtained from these drawings without creative labor.

[0029] Figure 1 It is a three-dimensional structure schematic view of the vector seal of the present application.

[0030] Figure 2 It is a meridian plane section view of the present application.

[0031] Figure 3 It is a schematic view of the tooth tip jet bypass structure on the sealing cavity of the present application.

[0032] Figure 4 It is a schematic view of the sealing cavity structure of the present application.

[0033] Figure 5 It is a schematic view of the traditional labyrinth seal.

[0034] Figure 6 It is a schematic view of the vector seal of the present application.

[0035] Figure 7 It is the flow line radial deflection characteristic of the traditional labyrinth seal.

[0036] Figure 8 It is the flow line radial deflection characteristic of the vector seal of the present application.

[0037] Figure 9 It is the flow line circumferential deflection characteristic of the traditional labyrinth seal.

[0038] Figure 10 It is the flow line circumferential deflection characteristic of the vector seal of the present application.

[0039] The reference signs in the drawings are represented as:

[0040] 1, air inlet; 2, stator shell containing sealing teeth; 3, tooth tip jet bypass; 4, vector sealing cavity; 5, rotor; 6, air outlet. DETAILED DESCRIPTION

[0041] The technical scheme in the embodiments of the present application will be described clearly and completely in combination with the drawings in the embodiments of the present application, obviously, the described embodiments are only some embodiments of the present application, and not all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by the ordinary skilled in the art without creative labor are within the protection scope of the present application.

[0042] Embodiment:

[0043] A novel turbine vector seal structure, comprising: a seal-tooth-containing stator shell 2, a tooth-tip jet bypass 3, a rotor 5, and a vector seal cavity 4 composed of the seal-tooth-containing stator shell 2 and the rotor 5. The seal-tooth-containing stator shell 2 and the rotor 5 are coaxially arranged.

[0044] The vector seal cavity 4 is a mirror-symmetrical vector nozzle structure, which comprises multiple seal cavities connected in sequence and having double throats, and the vector nozzle structure is axially parallel to the rotor 5, and adjacent two seal cavities share one throat, as shown in Figures 3-4 The seal cavities are sequentially divided into expansion sections and contraction sections along the airflow direction, and a tooth-tip jet bypass 3 is arranged between the throats downstream from the middle of the contraction sections in a one-to-one correspondence, and the tooth-tip jet bypass 3 is formed by opening a channel in the seal-tooth-containing stator shell 2. The inlet of the tooth-tip jet bypass 3 is relative to a circle around the axis of the rotor 5, and the inlet of the tooth-tip jet bypass 3 is relative to a straight line extending inward along the axial direction of the rotor 5 from the middle of the contraction section to form a ring structure; the outlet of the tooth-tip jet bypass 3 is connected from the inlet and extends linearly to the middle of the throat, and the outlet of the tooth-tip jet bypass 3 has multiple groups of circumferential uniform distribution,

[0045] The extension direction of the outlet of the tooth-tip jet bypass 3 is perpendicular to the axial direction of the rotor 5. In the plane composed of multiple tooth-tip jet bypasses 3, the outlet of the tooth-tip jet bypass 3 is inclined towards the rotor 5 to form a jet inclination angle.

[0046] The jet inclination angle is formed by taking the end of the inlet of the tooth-tip jet bypass 3 as the center, and taking the extension direction of the outlet of the tooth-tip jet bypass 3, the end of the inlet of the tooth-tip jet bypass 3 and the axis of the rotor 5 as two sides.

[0047] The ratio of the expansion section to the contraction section is controlled to be 2:1-3:1, and the expansion angle of the expansion section is controlled to be 10°-90°; and the contraction angle of the contraction section is controlled to be 90°-170°.

[0048] As shown in Figure 1 , Figure 2 , the working medium flows from the airflow inlet 1 to the airflow outlet 6. When the working medium flows through the seal tooth tip (throat), a throttling effect is generated, the pressure energy of the working medium is converted into kinetic energy, and the pressure at the tooth tip is less than the pressure in the upstream seal cavity. Under the driving of the pressure difference, a reverse rotational flow is formed in the tooth-tip bypass. Under the action of the jet flow, the main leakage flow forms a radial-circumferential composite deflection in the vector seal cavity 4. Among them, the radial deflection component can effectively enhance the turbulent kinetic energy dissipation in the cavity and improve the leakage flow resistance, and the circumferential deflection component can suppress the circumferential flow in the seal and suppress the occurrence of airflow excitation from the source.

[0049] In addition, the regulation effect of the vector seal is self-adaptively adjusted with the change of the pressure difference between the inlet and outlet of the seal.

[0050] The utility model discloses a flow field reconstruction in the sealing cavity is realized through the synergy of jet flow induction and cavity configuration improvement.

[0051] As shown in Figures 5-10 The utility model discloses a vector seal performance advantage is verified through the comparison with traditional labyrinth seal. As shown in Figure 5 、 Figure 6 The specific geometric parameters are shown in table 1, and the numerical method key parameter setting and operating condition are shown in table 2.

[0052] Table 1 geometric parameters of traditional labyrinth seal and vector seal

[0053]

[0054] Table 2 numerical method key parameter setting and operating condition of traditional labyrinth seal and vector seal

[0055]

[0056] Leakage reduction performance:

[0057] Figure 7 And Figure 8 The radial deflection characteristics of the flow lines of the labyrinth seal and the vector seal are compared. In the labyrinth seal, the leakage flow passes through the sealing domain at a relatively high speed, and the leakage path presents a straight line state, and the air permeation effect is obvious. In the vector seal, the leakage flow is obviously deflected radially under the mixing action of the tooth tip, and a complex flow pattern of bending and twisting is formed. This flow pattern not only prolongs the leakage path, suppresses the air permeation effect, but also enhances the turbulent energy dissipation in the cavity. At the same time, the "air curtain barrier" formed by the tooth tip jet at the inlet of each sealing cavity effectively improves the local flow resistance, and further enhances the leakage suppression effect. It is found that the leakage amount of the vector seal is reduced by about 36% compared with the labyrinth seal, which verifies the starting point of the vector seal for improving the leakage performance by reconstructing the radial flow field.

[0058] Vibration suppression performance:

[0059] Circumferential flow is the source of inducing fluid excitation of the seal, and whether the circumferential flow can be suppressed or even reversed is the key to realize vibration suppression. Figure 9 And Figure 10The flow line deflection characteristics of vector seal and traditional labyrinth seal are compared. The research results show that in the labyrinth seal, with the development of leakage flow, the overall flow field shape presents a significant circumferential deflection phenomenon in the same rotation direction; while in the vector seal, under the induction of the reverse rotation jet flow, the overall sealing domain presents a circumferential flow shape in the reverse rotation direction, and the circumferential flow is completely reversed. The research finds that the effective damping of the vector seal is doubled compared with the labyrinth seal, verifying the purpose of the vector seal to improve the "vibration suppression" performance by regulating the circumferential flow.

[0060] In the description of the present specification, the description referring to the terms "one embodiment", "an example", "a specific example" and the like means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0061] The preferred embodiments of the application disclosed above are only used to help explain the application. The preferred embodiments do not describe all the details, nor limit the application to the specific embodiments described. Obviously, according to the content of the present specification, many modifications and changes can be made. The present specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the application, so that the skilled in the art can well understand and utilize the application. The application is limited by the claims and their entire scope and equivalents.

Claims

1. A novel turbine mechanical vector sealing structure, comprising a vector sealing cavity (4) formed between a stator housing (2) containing sealing teeth and a rotor (5), characterized in that: The vector sealing cavity (4) has a mirror-symmetrical vector nozzle structure, which includes a multi-stage sealing cavity with a double throat connected end to end. The sealed cavity is divided into an expansion section and a contraction section in sequence along the airflow direction, and a tooth tip jet bypass (3) is provided between the contraction section and the throat adjacent to its downstream end.

2. The novel turbine mechanical vector sealing structure according to claim 1, characterized in that: The tooth tip jet bypass (3) is set on the stator housing (2) containing the sealing tooth.

3. The novel turbine mechanical vector sealing structure according to claim 2, characterized in that: The outlet of the tooth tip jet bypass (3) has multiple sets of outlets evenly arranged around the axis of the rotor (5).

4. The novel turbine mechanical vector sealing structure according to claim 3, characterized in that: The outlet extension directions of the multiple sets of tooth tip jet bypasses (3) are located in the same plane and are perpendicular to the axial direction of the nozzle-type structure.

5. A novel turbine mechanical vector sealing structure according to claim 4, characterized in that: The jet angle formed between the outlet direction of the tooth tip jet bypass (3) and the rotor (5) in the plane is 30°-60°.

6. A novel turbine mechanical vector sealing structure according to claim 2, characterized in that: The inlet of the tooth tip jet bypass (3) extends in a straight line from the middle of the contraction section along the axis of the sealing cavity.

7. A novel turbine mechanical vector sealing structure according to claim 6, characterized in that: The inlet of the tooth tip jet bypass (3) is arranged to surround the axis of the rotor (5) in one circle.

8. The novel turbine mechanical vector sealing structure according to claim 1, characterized in that: The ratio of the expansion section to the contraction section along the axis of the sealed cavity is 2:1 to 3:

1.

9. A novel turbine mechanical vector sealing structure according to claim 8, characterized in that: The expansion segment expands linearly and the contraction segment contracts linearly and the expansion segment expands linearly and the contraction ....

10. A novel turbine mechanical vector sealing structure according to claim 9, characterized in that: The expansion angle of the expansion section is 10°-90°; the contraction angle of the contraction section is 90°-170°.

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