A shaft end sealing device and design optimization method suitable for high-power turbines

Abstract

This invention provides a shaft end sealing device and its design optimization method suitable for high-power turbines. The shaft end sealing device includes a rotor, a housing, a flow curtain sealing air inlet unit, a kinetic energy blocking unit, flow curtain sealing fins, and labyrinth sealing teeth. The housing is sleeved on the outside of the rotor, and a chamber sealing channel is formed between the rotor and the housing. The flow curtain sealing air inlet unit is fixed on the outside of the housing and forms a preset angle with the housing. The flow curtain sealing air inlet unit is hollow inside, forming an air inlet chamber that communicates with the chamber sealing channel. The kinetic energy blocking unit is arranged around the outside of the rotor. The flow curtain sealing fins are disposed on the inner wall of the housing. The labyrinth sealing teeth are disposed on the inner wall of the housing, and the labyrinth sealing teeth are located on the side of the flow curtain sealing fins away from the kinetic energy blocking unit. One technical effect of this invention is that it can improve both the heat-to-work conversion efficiency and the stability of high-power turbines.

Description

Technical Field

[0001] This invention belongs to the field of turbomachinery design technology, specifically relating to a shaft end sealing device and design optimization method suitable for high-power turbines. Background Technology

[0002] Turbomachinery is an important rotating device for heat-to-work conversion, and its internal sealing devices play a crucial role in sealing the fluid inside. Therefore, research on turbomachinery seals has always been a hot topic. For turbomachinery using high-pressure, high-density supercritical fluids as the working medium, the sealing performance and dynamics of its sealing devices have become key issues affecting operational efficiency and stability.

[0003] For internal sealing devices in turbomachinery, they are mainly divided into contact seals and non-contact seals. Among them, non-contact seals are the most common type of seal in turbomachinery 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 high-power, high-pressure-ratio turbines, when the labyrinth seal has fewer sealing teeth, it cannot completely seal the working fluid inside the turbine, resulting in a large amount of working fluid leakage and a decrease in turbine efficiency. However, when the number of turbine sealing teeth increases, the rotor dynamics of the turbine deteriorates, reducing the stability of turbine operation.

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

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

[0006] According to a first aspect of the present invention, a shaft end sealing device suitable for high-power turbines is provided, comprising a rotor, a housing, a flow curtain sealing air intake unit, a kinetic energy blocking unit, flow curtain sealing fins and labyrinth sealing teeth, wherein the housing is sleeved on the outside of the rotor, and a chamber sealing channel is formed between the rotor and the housing.

[0007] The flow curtain sealing air intake unit is fixed to the outside of the housing and forms a preset angle with the housing; the interior of the flow curtain sealing air intake unit is hollow to form an air intake chamber that communicates with the chamber sealing channel;

[0008] The kinetic energy blocking unit is arranged around the outside of the rotor, and the kinetic energy blocking unit is located on the side of the flow curtain sealing air inlet unit away from the leakage inlet.

[0009] The flow curtain sealing fins are disposed on the inner wall of the housing, and the flow curtain sealing fins are located on the side of the kinetic energy blocking unit away from the flow curtain sealing air intake unit.

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

[0011] With the cooperation of the kinetic energy blocking unit and the flow curtain sealing fins, 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 sealing teeth are spaced apart on the inner wall of the housing, and the number of the labyrinth sealing teeth is no more than 3.

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

[0014] Optionally, the shape of the labyrinth sealing teeth is 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 intake 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 intake unit is half the distance d between the flow curtain sealing fin and the flow curtain sealing air intake 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, a design optimization method for a shaft end sealing device suitable for high-power turbines is provided, comprising the following steps:

[0019] Step S1: Determine the sealing height b of the chamber sealing channel based on the design boundary conditions of the axial flow turbine, and initialize the distance e between the flow curtain sealing fins and the rotor surface.

[0020] Step S2: Determine the variable operating condition range and maximum pressure of the chamber sealing channel;

[0021] Step S3: Determine the width a and tilt angle α of the intake chamber based on the structural parameters of the chamber sealing channel, the range of variable operating conditions, and the maximum pressure.

[0022] Step S4: Calculate the distance c between the kinetic energy blocking unit and the air intake chamber, the distance d between the flow curtain sealing fins and the flow curtain sealing air intake unit, the pitch f of the labyrinth sealing teeth, and determine the height h of the kinetic energy blocking unit using a three-dimensional numerical method.

[0023] Step S5: Use 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: Determine the sealing performance of the shaft end sealing device based on 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 can be optimized again by changing the sealing geometry parameters of the shaft end sealing device or reducing the vortex effect.

[0027] Optionally, when changing the sealing geometry parameters of the shaft end sealing device, the distance e between the flow curtain sealing fins and the rotor surface is adjusted, and steps S2 to S7 are repeated.

[0028] When using a method to reduce the vortex effect, adjust the height h of the kinetic energy blocking unit and repeat steps S4 to S7.

[0029] One technical advantage of this invention is that:

[0030] In this embodiment, by adding flow curtain sealing fins before the labyrinth sealing teeth and by introducing high-pressure gas from 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 not only improves the sealing performance of the turbine, thereby improving the heat-to-work conversion efficiency of the high-power turbine, but also reduces the number of labyrinth sealing teeth, reduces the airflow excitation force, and thus improves the stability of the high-power turbine.

[0031] In addition, this optimized design method for shaft end sealing devices applicable to high-power turbines enables the design and optimization of shaft end sealing devices, further improving the design and operation level of turbomachinery. Attached Figure Description

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

[0033] Figure 2 This is a flowchart illustrating a design optimization method for a shaft end sealing device suitable for high-power turbines according to an embodiment of the present invention.

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

[0035] In the diagram: 1. Rotor; 2. Housing; 3. Flow curtain sealing air intake unit; 31. Air intake chamber; 4. Kinetic energy blocking unit; 5. Flow curtain sealing fins; 6. Labyrinth sealing teeth; 7. Chamber sealing channel. Detailed Implementation

[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, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0037] The embodiments of this application will now be described in detail. Examples of these embodiments are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.

[0038] The terms "first" and "second" in the specification and claims of this application may explicitly or implicitly include one or more of the features. In the description of this application, unless otherwise stated, "multiple" means two or more. Furthermore, "and / or" in the specification and claims indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0039] In the description of this application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0040] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0041] According to a first aspect of the invention, see Figure 1 This invention provides a shaft end sealing device suitable for high-power turbines, which can improve the sealing characteristics of high-power turbines and reduce leakage, while also improving the damping characteristics of the shaft end sealing device to ensure the stable operation of high-power turbines.

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

[0043] The flow curtain sealing air intake unit 3 is fixed to the outside of the housing 2 and forms a preset angle with the housing 2; the interior of the flow curtain sealing air intake unit 3 is hollow to form an air intake chamber 31 that communicates with the chamber sealing channel 7;

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

[0045] The flow curtain sealing fins 5 are disposed on the inner wall of the housing 2, and the flow curtain sealing fins 5 are located on the side of the kinetic energy blocking unit 4 away from the flow curtain sealing air intake unit 3.

[0046] The labyrinth sealing teeth 6 are disposed on the inner wall of the housing 2, and the labyrinth sealing teeth 6 are located on the side of the flow curtain sealing fins 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 fins 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 devices, although the sealing teeth of the labyrinth seal can reduce the leakage of the working fluid inside the turbine, the presence of the sealing teeth significantly increases the excitation force of the airflow. Moreover, the more sealing teeth there are, the greater the excitation force and the worse the dynamic characteristics of rotor 1.

[0049] In this embodiment, by adding flow curtain sealing fins 5 before the labyrinth sealing teeth 6 and by introducing high-pressure gas from the turbine into the chamber sealing channel 7 to form a vortex, the pressure of the leakage flow entering the labyrinth sealing teeth 6 is reduced. This not only improves the sealing performance of the turbine, thereby improving the heat-to-work conversion efficiency of the high-power turbine, but also reduces the number of labyrinth sealing teeth 6, reduces the airflow excitation force, and thus improves the stability of the high-power turbine.

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

[0051] Optionally, a plurality of the labyrinth sealing teeth 6 are spaced apart on the inner wall of the housing 2, and the number of the labyrinth sealing teeth 6 is no more than 3. This can effectively reduce the airflow excitation force of the chamber sealing channel 7.

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

[0053] Optionally, the labyrinth sealing teeth 6 can be flat, high and low, pointed, or blunt. This gives the shaft end sealing device a better sealing effect.

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

[0055] Optionally, the distance d between the flow curtain sealing fin 5 and the flow curtain sealing air intake 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 intake unit 3 is half the distance d between the flow curtain sealing fin 5 and the flow curtain sealing air intake 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] 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 housing 2; the sealing height b of the chamber sealing channel 7 and the distance e between the flow curtain sealing fins 5 and the surface of the rotor 1 are determined by the boundary conditions of the turbine structure.

[0057] For example, a dimensionless parameter A is defined as the ratio of the width a of the intake chamber 31 to the sealing height b of the chamber sealing channel 7, which is used to evaluate the intensity of the vortex in the chamber sealing channel 7.

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

[0059] According to a second aspect of the invention, see Figure 2 and Figure 3 This paper provides a design optimization method for shaft end sealing devices suitable for high-power turbines, including the following steps:

[0060] Step S1: Determine the sealing height b of the chamber sealing channel 7 based on the design boundary conditions of the axial flow turbine, and initialize the distance e between the flow curtain sealing fins 5 and the surface of the rotor 1.

[0061] Step S2: Determine the variable operating condition range and maximum pressure of the chamber sealing channel 7;

[0062] Step S3: Based on the structural parameters of the chamber sealing channel 7, the range of variable operating conditions, and the maximum pressure, determine the width a and tilt angle α of the air intake chamber 31 (that is, the angle between the flow curtain sealing air intake unit and the housing).

[0063] Step S4: Calculate the distance c between the kinetic energy blocking unit 4 and the air intake chamber 31, the distance d between the flow curtain sealing fins 5 and the flow curtain sealing air intake unit 3, the pitch f of the labyrinth sealing teeth 6, and determine the height h of the kinetic energy blocking unit 4 using a three-dimensional numerical method.

[0064] Step S5: Use 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: Determine the sealing performance of the shaft end sealing device based on 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 this embodiment of the application, the optimized design method for shaft end sealing devices suitable for high-power turbines can realize the design and optimization of shaft end sealing devices, and further improve the design and operation level of turbomachinery.

[0068] Optionally, in step S7, if the sealing performance does not meet the requirements, the shaft end sealing device can be further optimized by changing the sealing geometry parameters or reducing the vortex effect. This can effectively improve the sealing performance of high-power turbines.

[0069] Optionally, when changing the sealing geometry parameters of the shaft end sealing device, 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 vortex effect is reduced, the height h of the kinetic energy blocking unit 4 is adjusted, and steps S4 to S7 are repeated.

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

[0072] It is understood that the above embodiments are merely exemplary implementations used to illustrate the principles of the present invention, and the present invention is not limited thereto. For those skilled 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 high-power turbines, characterized in that, It includes a rotor, a housing, a flow curtain sealing air intake unit, a kinetic energy blocking unit, flow curtain sealing fins and labyrinth sealing teeth. The housing is sleeved on the outside of the rotor, and a chamber sealing channel is formed between the rotor and the housing. The flow curtain sealing air intake unit is fixed to the outside of the housing and forms a preset angle with the housing; the interior of the flow curtain sealing air intake unit is hollow to form an air intake chamber that communicates with the chamber sealing channel; The width of the air intake chamber is 1.0~1.5mm, and the preset included angle is 45°~60°; The kinetic energy blocking unit is arranged around the outside of the rotor, and the kinetic energy blocking unit is located on the side of the flow curtain sealing air inlet unit away from the leakage inlet. The flow curtain sealing fins are disposed on the inner wall of the housing, and the flow curtain sealing fins are located on the side of the kinetic energy blocking unit away from the flow curtain sealing air intake unit. The labyrinth sealing teeth are disposed on the inner wall of the housing, and the labyrinth sealing teeth are located on the side of the flow curtain sealing fin away from the kinetic energy blocking unit; The distance d between the flow curtain sealing fin and the flow curtain sealing air intake 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 intake unit is half the distance d between the flow curtain sealing fin and the flow curtain sealing air intake 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. With the cooperation of the kinetic energy blocking unit and the flow curtain sealing fins, 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 for high-power turbines according to claim 1, characterized in that, Multiple labyrinth sealing teeth are spaced apart on the inner wall of the housing, and the number of labyrinth sealing teeth is no more than 3.

3. The shaft end sealing device for high-power turbines according to claim 1, characterized in that, The shape of the labyrinth sealing teeth can be flat, high and low, pointed or blunt.

4. The shaft end sealing device for high-power turbines according to claim 1, characterized in that, The flow curtain sealing fins are flat teeth.

5. The shaft end sealing device for high-power turbines according to claim 1, characterized in that, The distance between the labyrinth seal tooth and the rotor surface is equal to the distance e between the flow curtain seal fin and the rotor surface.

6. A design optimization method for a shaft end sealing device suitable for high-power turbines, characterized in that, Includes the following steps: Step S1: Determine the sealing height b of the chamber sealing channel based on the design boundary conditions of the axial flow turbine, and initialize the distance e between the flow curtain sealing fins and the rotor surface. Step S2: Determine the variable operating condition range and maximum pressure of the chamber sealing channel; Step S3: Determine the width a and tilt angle α of the intake chamber based on the structural parameters of the chamber sealing channel, the range of variable operating conditions, and the maximum pressure. Step S4: Calculate the distance c between the kinetic energy blocking unit and the air intake chamber, the distance d between the flow curtain sealing fins and the flow curtain sealing air intake unit, the pitch f of the labyrinth sealing teeth, and determine the height h of the kinetic energy blocking unit using a three-dimensional numerical method. Step S5: Use 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: Determine the sealing performance of the shaft end sealing device based on 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.

7. The design optimization method for a shaft end sealing device suitable for high-power turbines according to claim 6, characterized in that, In step S7, if the sealing performance does not meet the requirements, the shaft end sealing device is further optimized by changing the sealing geometry parameters of the shaft end sealing device or reducing the vortex effect.

8. The design optimization method for a shaft end sealing device suitable for high-power turbines according to claim 7, characterized in that, When changing the sealing geometry parameters of the shaft end sealing device, adjust the distance e between the flow curtain sealing fins and the rotor surface, and repeat steps S2 to S7. When using a method to reduce the vortex effect, adjust the height h of the kinetic energy blocking unit and repeat steps S4 to S7.

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