Shaft end sealing device suitable for high-power turbine and design optimization method

Abstract

The invention provides a shaft end sealing device suitable for a high-power turbine and a design optimization method.The shaft end sealing device comprises a rotor, a shell, a flow curtain sealing air inlet unit, a kinetic energy retarding unit, flow curtain sealing fins and labyrinth sealing teeth, the rotor is sleeved with the shell, and a cavity sealing channel is formed between the rotor and the shell; the flow curtain sealing air inlet unit is fixed to the outer side of the shell, and a preset included angle is formed between the flow curtain sealing air inlet unit and the shell. The interior of the flow curtain sealing air inlet unit is hollow, and an air inlet cavity communicated with the cavity sealing channel is formed in the flow curtain sealing air inlet unit. The kinetic energy retarding unit is annularly arranged on the outer side of the rotor; the flow curtain sealing fins are arranged on the inner wall of the shell; the labyrinth sealing teeth are arranged on the inner wall of the shell and located on the sides, away from the kinetic energy retarding units, of the flow curtain sealing fins. The high-power turbine has the technical effects that the heat-power conversion efficiency of the high-power turbine can be improved, and the stability of the high-power turbine can also be improved.

Description

Technical Field

[0001] The invention belongs to the technical field of impeller machinery design, and in particular relates to a shaft end sealing device suitable for a high-power turbine and a design optimization method. Background Art

[0002] Impeller machinery is an important rotating device for heat-work conversion. Its internal sealing device plays a vital role in sealing the fluid inside the impeller machinery. Therefore, the research on impeller machinery seals has always been one of the hot topics. For impeller machinery with high-pressure, high-density supercritical fluid as the working fluid, the sealing performance and dynamics of its sealing device have also become one of the key issues affecting operating efficiency and stability.

[0003] The sealing devices inside the impeller machinery are mainly divided into contact seals and non-contact seals. Among them, non-contact seals have become the most common sealing type in the impeller machinery due to their good sealing performance, long service life and simple structure. Typical non-contact seals include labyrinth seals and gas seals. At present, for turbines with high power and high pressure ratio, when the labyrinth seal has fewer sealing teeth, it is impossible to completely seal the working fluid in the turbine, resulting in large leakage of working fluid and reduced turbine efficiency; however, when the number of turbine sealing teeth increases, the rotor dynamic characteristics of the turbine become worse, reducing the stability of turbine operation.

[0004] Therefore, there is an urgent need for a shaft end sealing device and an optimization design method suitable for high-power turbines, which aims to reduce the number of teeth of the labyrinth seal as much as possible while ensuring the sealing performance of the turbine, thereby improving the operating efficiency and stability of the high-power turbine and further improving the design and operation level of the impeller machinery. Summary of the invention

[0005] The present invention aims to solve at least one of the technical problems existing in the prior art and to provide a new technical solution for a shaft end sealing device and a design optimization method suitable for a high-power turbine.

[0006] According to a first aspect of the present invention, there is provided a shaft end sealing device suitable for a high-power turbine, comprising a rotor, a housing, a flow curtain seal air intake unit, a kinetic energy blocking unit, a flow curtain seal fin and a labyrinth seal tooth, wherein the housing is sleeved on the outer side of the rotor, and a chamber sealing channel is formed between the rotor and the housing;

[0007] The flow curtain sealed air inlet unit is fixed to the outer side of the shell and forms a preset angle with the shell; the interior of the flow curtain sealed air inlet unit is hollow to form an air inlet chamber connected to the chamber sealing channel;

[0008] The kinetic energy blocking unit is arranged in a ring on the outer side of the rotor, and the kinetic energy blocking unit is located on the side of the flow curtain seal air inlet unit away from the leakage flow inlet;

[0009] The flow curtain sealing fin is arranged on the inner wall of the shell, and the flow curtain sealing fin is located on the side of the kinetic energy blocking unit away from the flow curtain sealing air inlet unit;

[0010] The labyrinth seal teeth are arranged on the inner wall of the housing, and the labyrinth seal teeth are located on a side of the flow curtain seal fin away from the kinetic energy blocking unit;

[0011] With the cooperation of the kinetic energy blocking unit and the flow curtain sealing fin, high-pressure gas enters the chamber sealing channel from the air inlet chamber and forms a vortex in the chamber sealing channel to reduce the pressure of the leakage flow passing through the labyrinth sealing teeth.

[0012] Optionally, a plurality of the labyrinth seal teeth are arranged at intervals on the inner wall of the shell, and the number of the labyrinth seal teeth is no more than 3.

[0013] Optionally, the width of the air inlet chamber is 1.0-1.5 mm, and the preset angle is 45°-60°.

[0014] Optionally, the labyrinth seal teeth are in the shape of flat teeth, high and low teeth, pointed teeth or blunt teeth.

[0015] Optionally, the flow curtain sealing fins are flat teeth.

[0016] Optionally, the distance d between the flow curtain sealing fin and the flow curtain sealing air inlet unit is twice the sealing height b of the chamber sealing channel, the distance c between the kinetic energy blocking unit and the flow curtain sealing air inlet unit is 1 / 2 of the distance d between the flow curtain sealing fin and the flow curtain sealing air inlet unit, and the pitch f of the labyrinth sealing teeth is 20 times the distance e between the flow curtain sealing fin and the rotor surface.

[0017] Optionally, the distance between the labyrinth seal teeth and the rotor surface is equal to the distance e between the flow curtain seal fins and the rotor surface.

[0018] According to a second aspect of the present invention, there is provided a design optimization method for a shaft end sealing device applicable to a high-power turbine, comprising the following steps:

[0019] Step S1, determining the sealing height b of the chamber sealing channel according to the design boundary conditions of the axial flow turbine, and initializing the distance e between the flow curtain sealing fin and the rotor surface;

[0020] Step S2, determining the variable operating range and maximum pressure of the chamber sealing channel;

[0021] Step S3, determining the width a and the inclination angle α of the air inlet chamber according to the structural parameters of the chamber sealing channel, the variable operating range and the maximum pressure;

[0022] Step S4, calculating the distance c between the kinetic energy blocking unit and the air inlet chamber, the distance d between the flow curtain sealing fin and the flow curtain sealing air inlet unit, the pitch f of the labyrinth seal teeth, and determining the height h of the kinetic energy blocking unit by a three-dimensional numerical method;

[0023] Step S5, using three-dimensional numerical simulation technology to calculate the leakage of the shaft end sealing device and determine the vortex effect in the chamber sealing channel;

[0024] Step S6, determining the sealing performance of the shaft end sealing device according to the leakage of the shaft end sealing device and the vortex effect in the chamber sealing channel;

[0025] Step S7: If the sealing performance meets the requirements, the optimized design of the shaft end sealing device is completed.

[0026] Optionally, in step S7, if the sealing performance does not meet the requirements, the shaft end sealing device is optimized again by changing the sealing geometric parameters of the shaft end sealing device or reducing the vortex effect.

[0027] Optionally, when the sealing geometric parameters of the shaft end sealing device are changed, the distance e between the flow curtain sealing fin and the rotor surface is adjusted, and steps S2 to S7 are repeated;

[0028] When the method of reducing the vortex effect is adopted, the height h of the kinetic energy blocking unit is adjusted, and steps S4 to S7 are repeated.

[0029] A technical effect of the present invention is:

[0030] In an embodiment of the present application, by adding flow curtain sealing fins before the labyrinth sealing teeth and by introducing the high-pressure gas in the turbine into the chamber sealing channel to form a vortex, the pressure of the leakage flow entering the labyrinth sealing teeth is reduced. This can not only improve the sealing performance of the turbine, thereby improving the heat-to-work conversion efficiency of the high-power turbine, but also reduce the number of labyrinth sealing teeth, reduce the airflow excitation force, and thus improve the stability of the high-power turbine.

[0031] In addition, the optimization design method for the shaft end sealing device suitable for high-power turbines can realize the design and optimization of the shaft end sealing device and further improve the design and operation level of the impeller machinery. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 This is a schematic structural diagram of a shaft end sealing device suitable for a high-power turbine according to an embodiment of the present invention;

[0033] Figure 2 A schematic flow chart of a design optimization method for a shaft end sealing device applicable to a high-power turbine according to an embodiment of the present invention;

[0034] Figure 3 The present invention is a flowchart of a design optimization method for a shaft end sealing device suitable for a high-power turbine according to another embodiment of the present invention.

[0035] In the figure: 1. rotor; 2. shell; 3. flow curtain seal air intake unit; 31. air intake chamber; 4. kinetic energy blocking unit; 5. flow curtain seal fin; 6. labyrinth seal tooth; 7. chamber seal channel. DETAILED DESCRIPTION

[0036] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that unless otherwise specifically stated, the relative arrangement of components and steps, numerical expressions and numerical values ​​set forth in these embodiments do not limit the scope of the present application.

[0037] The embodiments of the present application will be described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application, and should not be construed as limitations on the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0038] The term "first" or "second" in the specification and claims of this application may include one or more of the features explicitly or implicitly. In the description of this application, unless otherwise specified, "plurality" means two or more. In addition, "and / or" in the specification and claims means at least one of the connected objects, and the character " / " generally means that the objects connected before and after are in an "or" relationship.

[0039] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0040] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0041] According to a first aspect of the present invention, see Figure 1 , provides a shaft end sealing device suitable for a high-power turbine, which can not only improve the sealing characteristics of the high-power turbine and reduce leakage, but also improve the anti-damping characteristics of the shaft end sealing device to ensure the stable operation of the high-power turbine.

[0042] Specifically, the shaft end sealing device suitable for high-power turbines includes a rotor 1, a housing 2, a flow curtain seal air intake unit 3, a kinetic energy blocking unit 4, a flow curtain seal fin 5 and a labyrinth seal tooth 6, wherein the housing 2 is sleeved on the outer side of the rotor 1, and a chamber sealing channel 7 is formed between the rotor 1 and the housing 2;

[0043] The flow curtain sealed air inlet unit 3 is fixed to the outer side of the housing 2 and forms a preset angle with the housing 2; the flow curtain sealed air inlet unit 3 is hollow inside to form an air inlet chamber 31 connected to the chamber sealing channel 7;

[0044] The kinetic energy blocking unit 4 is arranged around the outer side of the rotor 1, and the kinetic energy blocking unit 4 is located on the side of the flow curtain seal air inlet unit 3 away from the leakage inlet;

[0045] The flow curtain sealing fin 5 is arranged on the inner wall of the housing 2, and the flow curtain sealing fin 5 is located on the side of the kinetic energy blocking unit 4 away from the flow curtain sealing air inlet unit 3;

[0046] The labyrinth seal teeth 6 are arranged on the inner wall of the housing 2, and the labyrinth seal teeth 6 are located on the side of the flow curtain seal fin 5 away from the kinetic energy blocking unit 4;

[0047] With the cooperation of the kinetic energy blocking unit 4 and the flow curtain sealing fin 5 , high-pressure gas enters the chamber sealing channel 7 from the air inlet chamber 31 and forms a vortex in the chamber sealing channel 7 to reduce the pressure of the leakage flow passing through the labyrinth sealing teeth 6 .

[0048] It should be noted that in the existing turbine sealing device, although the sealing teeth of the labyrinth seal can reduce the leakage of the working fluid in the turbine, the existence of the sealing teeth significantly increases the airflow exciting force, and the more sealing teeth there are, the greater the exciting force is, and the worse the dynamic characteristics of the rotor 1 are.

[0049] In the embodiment of the present application, by adding a flow curtain sealing fin 5 before the labyrinth sealing tooth 6 and introducing the high-pressure gas in the turbine into the chamber sealing channel 7 to form a vortex, the pressure of the leakage flow entering the labyrinth sealing tooth 6 is reduced, which can not only improve the sealing performance of the turbine, thereby improving the heat-to-work conversion efficiency of the high-power turbine, but also reduce the number of labyrinth sealing teeth 6, reduce the airflow exciting force, and thus improve the stability of the high-power turbine.

[0050] Exemplarily, in order to ensure the performance of the flow curtain seal, the high-pressure gas passing through the air inlet chamber 31 of the flow curtain seal air inlet unit 3 should come from the inlet of the first stage of the turbine.

[0051] Optionally, a plurality of the labyrinth seal teeth 6 are arranged at intervals on the inner wall of the housing 2 , and the number of the labyrinth seal teeth 6 is not greater than 3. This can effectively reduce the airflow exciting force of the chamber sealing channel 7 .

[0052] Optionally, the width of the air inlet chamber 31 is 1.0-1.5 mm, and the preset angle is 45°-60°. This allows the high-pressure gas to form a vortex in the chamber sealing channel 7 through the air inlet chamber 31, thereby effectively reducing the pressure of the leakage flow passing through the labyrinth seal teeth 6.

[0053] Optionally, the labyrinth seal teeth 6 are in the shape of flat teeth, high and low teeth, sharp teeth or blunt teeth, which makes the shaft end sealing device have a better sealing effect.

[0054] Optionally, the flow curtain sealing fins 5 are flat teeth, which can better ensure the strength of the vortex effect inside the chamber sealing channel 7.

[0055] Optionally, the distance d between the flow curtain sealing fin 5 and the flow curtain sealing air inlet unit 3 is twice the sealing height b of the chamber sealing channel 7, the distance c between the kinetic energy blocking unit 4 and the flow curtain sealing air inlet unit 3 is 1 / 2 of the distance d between the flow curtain sealing fin 5 and the flow curtain sealing air inlet unit 3, and the pitch f of the labyrinth sealing teeth 6 is 20 times the distance e between the flow curtain sealing fin 5 and the surface of the rotor 1.

[0056] Among them, the sealing height b of the chamber sealing channel 7 is defined as the vertical distance between the rotor 1 and the inner wall of the shell 2; the sealing height b of the chamber sealing channel 7 and the distance e between the flow curtain sealing fin 5 and the surface of the rotor 1 are determined by the boundary conditions of the turbine structure.

[0057] Exemplarily, the dimensionless parameter A is defined as the ratio of the width a of the air inlet chamber 31 to the sealing height b of the chamber sealing channel 7 , and is used to evaluate the strength of the vortex in the chamber sealing channel 7 .

[0058] Optionally, the distance between the labyrinth seal teeth 6 and the surface of the rotor 1 is equal to the distance e between the flow curtain seal fins 5 and the surface of the rotor 1. This can further reduce the exciting force of the leakage flow in the chamber sealing channel 7.

[0059] According to the second aspect of the present invention, see Figure 2 and Figure 3 , provides a design optimization method for a shaft end sealing device suitable for a high-power turbine, comprising the following steps:

[0060] Step S1, determining the sealing height b of the chamber sealing channel 7 according to the design boundary conditions of the axial flow turbine, and initializing the distance e between the flow curtain sealing fin 5 and the surface of the rotor 1;

[0061] Step S2, determining the variable operating range and maximum pressure of the chamber sealing channel 7;

[0062] Step S3, according to the structural parameters of the chamber sealing channel 7, the variable operating range and the maximum pressure, the width a and the inclination angle α (that is, the angle between the flow curtain sealing air inlet unit and the shell) of the air inlet chamber 31 are determined;

[0063] Step S4, calculating the distance c between the kinetic energy blocking unit 4 and the air inlet chamber 31, the distance d between the flow curtain sealing fin 5 and the flow curtain sealing air inlet unit 3, the pitch f of the labyrinth seal teeth 6, and determining the height h of the kinetic energy blocking unit 4 by a three-dimensional numerical method;

[0064] Step S5, using three-dimensional numerical simulation technology to calculate the leakage of the shaft end sealing device and determine the vortex effect in the chamber sealing channel 7;

[0065] Step S6, determining the sealing performance of the shaft end sealing device according to the leakage of the shaft end sealing device and the vortex effect in the chamber sealing channel 7;

[0066] Step S7: If the sealing performance meets the requirements, the optimized design of the shaft end sealing device is completed.

[0067] In the embodiment of the present application, the optimization design method for the shaft end sealing device suitable for a high-power turbine can realize the design and optimization of the shaft end sealing device and further improve the design and operation level of the impeller machinery.

[0068] Optionally, in step S7, if the sealing performance does not meet the requirements, the shaft end sealing device is optimized again by changing the sealing geometric parameters of the shaft end sealing device or reducing the vortex effect, which can effectively improve the sealing performance of the high-power turbine.

[0069] Optionally, when the sealing geometric parameters of the shaft end sealing device are changed, the distance e between the flow curtain sealing fin 5 and the surface of the rotor 1 is adjusted, and steps S2 to S7 are repeated;

[0070] When the method of reducing the vortex effect is adopted, the height h of the kinetic energy blocking unit 4 is adjusted, and steps S4 to S7 are repeated.

[0071] In the above implementation, the operation method is simple, and the shaft end sealing device can be quickly optimized again, with a good optimization effect.

[0072] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A shaft end sealing device suitable for a high-power turbine, characterized in that: It includes a rotor, a shell, a flow curtain seal air intake unit, a kinetic energy blocking unit, a flow curtain seal fin and a labyrinth seal tooth, wherein the shell is sleeved on the outer side of the rotor, and a chamber sealing channel is formed between the rotor and the shell; The flow curtain sealed air inlet unit is fixed to the outer side of the shell and forms a preset angle with the shell; the interior of the flow curtain sealed air inlet unit is hollow to form an air inlet chamber connected to the chamber sealing channel; The kinetic energy blocking unit is arranged in a ring on the outer side of the rotor, and the kinetic energy blocking unit is located on the side of the flow curtain seal air inlet unit away from the leakage flow inlet; The flow curtain sealing fin is arranged on the inner wall of the shell, and the flow curtain sealing fin is located on the side of the kinetic energy blocking unit away from the flow curtain sealing air inlet unit; The labyrinth seal teeth are arranged on the inner wall of the housing, and the labyrinth seal teeth are located on a side of the flow curtain seal fin away from the kinetic energy blocking unit; With the cooperation of the kinetic energy blocking unit and the flow curtain sealing fin, high-pressure gas enters the chamber sealing channel from the air inlet chamber and forms a vortex in the chamber sealing channel to reduce the pressure of the leakage flow passing through the labyrinth sealing teeth.

2. The shaft end sealing device suitable for a high-power turbine according to claim 1, characterized in that: A plurality of the labyrinth seal teeth are arranged at intervals on the inner wall of the housing, and the number of the labyrinth seal teeth is no more than 3.

3. The shaft end sealing device suitable for a high-power turbine according to claim 1, characterized in that: The width of the air inlet chamber is 1.0-1.5 mm, and the preset angle is 45°-60°.

4. The shaft end sealing device suitable for a high-power turbine according to claim 1, characterized in that: The labyrinth seal teeth are in the shape of flat teeth, high and low teeth, sharp teeth or blunt teeth.

5. The shaft end sealing device suitable for a high-power turbine according to claim 1, characterized in that: The flow curtain sealing fins are flat teeth.

6. The shaft end sealing device suitable for high-power turbine according to claim 2, characterized in that: The distance d between the flow curtain sealing fin and the flow curtain sealing air inlet unit is twice the sealing height b of the chamber sealing channel, the distance c between the kinetic energy blocking unit and the flow curtain sealing air inlet unit is 1 / 2 of the distance d between the flow curtain sealing fin and the flow curtain sealing air inlet unit, and the pitch f of the labyrinth sealing teeth is 20 times the distance e between the flow curtain sealing fin and the rotor surface.

7. The shaft end sealing device suitable for a high-power turbine according to claim 6, characterized in that: The distance between the labyrinth seal teeth and the rotor surface is equal to the distance e between the flow curtain seal fins and the rotor surface.

8. A design optimization method for a shaft end sealing device suitable for a high-power turbine, characterized in that: The steps include: Step S1, determining the sealing height b of the chamber sealing channel according to the design boundary conditions of the axial flow turbine, and initializing the distance e between the flow curtain sealing fin and the rotor surface; Step S2, determining the variable operating range and maximum pressure of the chamber sealing channel; Step S3, determining the width a and the inclination angle α of the air inlet chamber according to the structural parameters of the chamber sealing channel, the variable operating range and the maximum pressure; Step S4, calculating the distance c between the kinetic energy blocking unit and the air inlet chamber, the distance d between the flow curtain sealing fin and the flow curtain sealing air inlet unit, the pitch f of the labyrinth seal teeth, and determining the height h of the kinetic energy blocking unit by a three-dimensional numerical method; Step S5, using three-dimensional numerical simulation technology to calculate the leakage of the shaft end sealing device and determine the vortex effect in the chamber sealing channel; Step S6, determining the sealing performance of the shaft end sealing device according to the leakage of the shaft end sealing device and the vortex effect in the chamber sealing channel; Step S7: If the sealing performance meets the requirements, the optimized design of the shaft end sealing device is completed.

9. The design optimization method for a shaft end seal device suitable for a high-power turbine according to claim 8, characterized in that: In step S7, if the sealing performance does not meet the requirements, the shaft end sealing device is optimized again by changing the sealing geometric parameters of the shaft end sealing device or reducing the vortex effect.

10. The design optimization method for a shaft end sealing device suitable for a high-power turbine according to claim 9, characterized in that: When the sealing geometric parameters of the shaft end sealing device are changed, the distance e between the flow curtain sealing fin and the rotor surface is adjusted, and steps S2 to S7 are repeated; When the method of reducing the vortex effect is adopted, the height h of the kinetic energy blocking unit is adjusted, and steps S4 to S7 are repeated.

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