WO2023051159A1

WO2023051159A1 - Gas path system for gas bearing, and microturbine

Info

Publication number: WO2023051159A1
Application number: PCT/CN2022/116636
Authority: WO
Inventors: 靳普
Original assignee: 永旭腾风新能源动力科技（北京）有限公司; 靳普
Priority date: 2021-09-28
Filing date: 2022-09-01
Publication date: 2023-04-06
Also published as: CN113898670A

Abstract

A gas path system for a gas bearing (100). The gas path system comprises a gas source gas path (A), a gas supply gas path (B), a bearing gas path (C) and a buffer tank (200), wherein an input end of the bearing gas path (C) is in communication with the buffer tank (200), and an output end of the bearing gas path is in communication with the gas bearing (100); an input end of the gas source gas path (A) is in communication with an external gas source (300), an output end of the gas source gas path is in communication with the buffer tank (200), and the gas source gas path (A) is used for supplying gas to the gas bearing (100) by means of the buffer tank (200) when the gas bearing (100) is in a static pressure working mode or switched from a dynamic pressure working mode to the static pressure working mode; and an input end of the gas supply gas path (B) is in communication with a gas supply gas source (400), an output end of the gas supply gas path is in communication with the buffer tank (200), and the gas supply gas path (B) is used for supplying gas to the gas bearing (100) by means of the buffer tank (200) when the gas bearing (100) is switched from the static pressure working mode to the dynamic pressure working mode. Further provided are a control method of the gas path system for the gas bearing (100), and a microturbine comprising the gas path system. By means of providing the buffer tank (200) and the gas supply gas path (B), the gas path system can realize smooth switching of the gas bearing (100) from "the static pressure working mode" to "the dynamic pressure working mode", thereby ensuring the stability of the working state of a rotor.

Description

Gas path system and micro gas turbine for gas bearing

technical field

The invention relates to a gas path system for a gas bearing and a micro gas turbine including the gas path system, belonging to the technical field of bearings.

Background technique

The micro gas turbine uses continuously flowing gas as the working medium to drive the impeller to rotate at high speed, and convert the energy of the fuel into useful work. It is a rotating impeller heat engine. It mainly includes three parts: compressor, combustion chamber and turbine. The compressor sucks in air from the external atmosphere and compresses it to pressurize it. At the same time, the temperature of the air also increases accordingly; Mixed combustion generates high-temperature and high-pressure gas; then it enters the turbine and expands to do work, pushing the turbine to drive the compressor and the external load rotor to rotate together at high speed, realizing the partial conversion of the chemical energy of the gas or liquid fuel into mechanical work, and can be connected to generate electricity machine output power.

When the rotor rotates at high speed, the rotor will be subjected to radial force and axial force. In order to limit the radial and axial movement of the rotating shaft, radial bearings and thrust bearings need to be installed in the rotor system. Traditional radial bearings and thrust bearings are common contact bearings. As the rotor speed increases, especially when the rotor speed exceeds 40,000 revolutions per minute, ordinary contact bearings cannot meet the requirements due to large mechanical wear. operating speed requirements. Therefore, researchers have proposed a scheme to replace the original mechanical bearings with non-contact bearings, among which the most representative one is gas bearings.

Gas bearings (also known as air bearings) refer to bearings that use gas (usually air, but may also be other gases) as a lubricant. The air makes it form a lubricating air film with a certain load and rigidity in the gap, which can reduce the influence of friction on the motor spindle speed. Both the compressor and the turbine need to be installed on the main shaft through the gas bearing, so the operation stability of the gas bearing determines the operation stability of the whole unit.

In the existing related technologies, the gas bearing can support the static pressure working state and the dynamic pressure working state. The static pressure working state refers to supplying air to the gas bearing through an external air source, and the bearing blows air to the shaft surface through an orifice to A lubricating air film with a certain load and rigidity is formed in the gap between the bearing and the shaft surface, and the working process requires continuous air supply from an external air source. The dynamic pressure working state means that when the micro gas turbine reaches a certain speed, the tangential movement of the gas bearing surface is used to form a gas lubricating film, so that there is no need for continuous gas supply from an external gas source, and only the speed of the gas turbine reaches the predetermined speed during the start-up phase. The front air supply is enough, which can prolong the service life of the external air source equipment. However, at the moment when the dynamic and static pressure state of the gas bearing is switched, the shape of the gas film will fluctuate, which will affect the stability. Therefore, it is necessary to develop a solution to solve the problem of fluctuations in the "gas film form" at the moment of switching between the dynamic and static pressure states of the gas bearing.

Contents of the invention

Aiming at the above prior art, the present invention provides a gas circuit system for a gas bearing, and a micro gas turbine including the gas circuit system. The invention supplies air to the gas bearing by providing an air circuit system with a buffer tank and an air supply circuit to ensure the stability of the gas film when the dynamic and static pressure is switched.

The present invention is achieved through the following technical solutions:

A gas circuit system for a gas bearing, including a gas source gas circuit, a gas supply gas circuit, a bearing gas circuit and a buffer tank, wherein the input end of the bearing gas circuit communicates with the buffer tank, and the output end communicates with the gas bearing;

The input end of the gas source and gas path is connected with the external gas source, and the output end is connected with the buffer tank. The tank supplies gas to the gas bearing;

The input end of the supplementary air circuit is connected with the supplementary gas source, and the output end is connected with the buffer tank. The supplementary air circuit is used to supply the gas bearing through the buffer tank when the gas bearing is switched from the static pressure working mode to the dynamic pressure working mode. gas.

Further, the buffer tank is a rigid tank or an elastic tank; the elastic tank has a self-adjusting function, and can offset pressure fluctuations through expansion and contraction to enhance the buffering effect.

Further, a solenoid valve is provided on the gas source gas path to control the opening and closing of the gas path and the flow rate.

Further, a solenoid valve is provided on the supplementary air circuit to control the opening and closing of the air circuit and the flow rate.

Further, the external air source is selected from any one of a screw pump, a piston pump or a centrifugal pump.

Further, the supplementary gas source is selected from any one of a screw pump, a piston pump or a centrifugal pump.

Further, when the gas circuit system of the present invention is applied to a gas turbine, the supplementary gas source may be a compressor of the gas turbine, and the input end of the supplementary gas circuit communicates with the outlet of the compressor.

Further, the number of the gas bearings is more than two; the gas bearings are radial bearings, thrust bearings or radial thrust integrated bearings with the same air inlet.

Further, the bearing gas path includes more than two branches, and the number of branches corresponds to the number of gas bearings.

The control method for the gas circuit system of the gas bearing includes the following steps:

When the gas bearing is in the static pressure working mode, the gas is supplied by an external gas source: the pressure gas from the external gas source is passed into the buffer tank for buffering, and then distributed to the gas bearing through the buffer tank through the bearing gas circuit;

When the gas bearing is switched from the static pressure working mode to the dynamic pressure working mode, firstly control the opening of the supplementary gas circuit, supply gas from the supplementary gas source to the buffer tank, and then control the external gas source to stop the gas supply or control the gas source to close the gas circuit .

A micro gas turbine includes the above-mentioned gas path system for gas bearings.

In the prior art, when the gas bearing is switched from the "static pressure working state" to the "dynamic pressure working state", the gas in the gas film will flow to the gas path due to the sudden stop of the gas supply from the external gas source and the sudden drop in the pressure in the gas path , thus forming the phenomenon that the gas path draws air from the gas film, resulting in fluctuations in the shape of the gas film, and then disturbing the stability of the working state of the rotor. The gas circuit system of the present invention can realize the smooth switching of the gas bearing from the "static pressure working state" to the "dynamic pressure working state" by setting the buffer tank and the gas supply circuit, so as to ensure the stability of the rotor working state: on the one hand, the buffer Since the tank has a volume larger than that of the gas circuit, it can store relatively more gas to maintain the pressure, which can weaken the phenomenon of pumping gas from the gas film to a certain extent; , to further maintain the gas volume and pressure in the buffer tank, and then try to avoid drawing air from the gas film, so as to avoid the fluctuation of the gas film shape during switching and keep the gas film stable.

The gas circuit system of the present invention is provided with a buffer tank, which can limit and maintain a certain pressure, and can ease the pressure fluctuation of the gas entering the buffer tank, so as to keep the pressure of the gas going out of the buffer tank as stable as possible. In the present invention, by setting the buffer tank and the gas supply circuit, when the gas bearing is switched from the "static pressure working state" to the "dynamic pressure working state", the fluctuation of the gas film shape is limited to the greatest extent, and the gas film can be kept stable, thereby Realize smooth switching and ensure the stability of the working state of the rotor. The present invention can install electromagnetic valves on the air source air path and the air supplementary air path to control the opening and closing of the air path, without setting electromagnetic valves on the bearing air path (including each branch), so as to save the number of electromagnetic valves and save costs , and easy to maintain.

Various terms and phrases used herein have their ordinary meanings known to those skilled in the art. If the terms and phrases mentioned are inconsistent with the known meanings, the meanings expressed in the present invention shall prevail.

Description of drawings

Fig. 1: A schematic diagram of the structure of the gas circuit system used in the gas bearing of the present invention.

Fig. 2: A schematic diagram of the structure of the gas circuit system for the gas bearing of the present invention (the gas bearing is a gas bearing group).

Fig. 3: Schematic diagram of the control method of the gas circuit system of the present invention.

Among them, 100, gas bearing; 200, buffer tank; 300, external air source; 400, supplementary air source; 1, rotating shaft; 2, generator; 3, turbine; 110, first radial bearing; 120, thrust bearing ; 130, the second radial bearing; A, air source air path; B, air supply air path; C, bearing air path; C1, branch air path I; C2, branch air path II; C3, branch air path III.

Detailed ways

The present invention will be further described below in conjunction with embodiment. However, the scope of the present invention is not limited to the following examples. Those skilled in the art can understand that various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention.

Example 1

A gas circuit system for a gas bearing 100, including a gas source gas circuit A, a supplementary gas circuit B, a bearing gas circuit C and a buffer tank 200, as shown in Figure 1, wherein the input end of the bearing gas circuit C is connected to the The buffer tank 200 is in communication, and the output end is in communication with the gas bearing 100 .

The input end of the gas source gas path A is connected to the external gas source 300, and the output end is connected to the buffer tank 200. The gas source gas path A is used for the gas bearing 100 to be in the static pressure working mode or to switch from the dynamic pressure working mode to the static pressure working mode. mode, gas is supplied to the gas bearing 100 through the buffer tank 200 .

The input end of the air supply circuit B is connected with the air supply source 400, and the output end is connected with the buffer tank 200. The tank 200 supplies gas to the gas bearing 100 .

The buffer tank 200 can be a rigid tank body. At this time, the buffer tank 200 itself has no self-regulating function, and the buffering and stabilizing function is performed solely by the gas capacity, and the gas film stabilization during the dynamic and static pressure switching process is realized in conjunction with the gas supply circuit B.

The buffer tank 200 can also be an elastic tank body. In this case, the buffer tank 200 has a self-adjusting function, and can offset pressure fluctuations through expansion and contraction to enhance the buffering effect.

The air source air path A and the air supply air path B may be provided with solenoid valves to control the opening and closing and flow of the air paths.

The external air source 300 is selected from any one of a screw pump, a piston pump or a centrifugal pump.

The supplementary gas source 400 is selected from any one of a screw pump, a piston pump or a centrifugal pump. The pressure requirement and stability requirement of the supplementary gas source 400 may be lower than that of the gas source 300 . The supplementary gas source 400 can also be selected from a compressor (when the gas circuit system of this embodiment is applied to a gas turbine), and the input end of the supplementary gas circuit communicates with the outlet of the compressor.

The number of the gas bearing 100 can be more than two, and the gas bearing 100 can be a radial bearing, a thrust bearing or a radial thrust integrated bearing with the same air inlet, for example, two radial bearings (the first radial Bearing 110, the second radial bearing 130) and two thrust bearings 120 form a gas bearing group, as shown in Figure 2; correspondingly, the bearing gas path C can include multiple branches (as shown in Figure 2, including There are three branches of branch gas path I C1, branch gas path II C2 and branch gas path III C3, the branch gas path I C1 communicates with the first radial bearing 110, the branch gas path II C2 communicates with the thrust bearing 120, The branch gas path III (C3 communicates with the second radial bearing 130), and the number of branches corresponds to the number of gas bearings. In this way, solenoid valves can only be installed on the air source air path A and the supplementary air path B, and there is no need to install electromagnetic valves on the bearing air path C (including each branch), so as to save the number of solenoid valves, save costs, and facilitate maintenance .

Example 2

The control method for the gas circuit system (embodiment 1) of the gas bearing 100, as shown in Figure 3, the steps are as follows:

Step S1: When the gas bearing 100 is in the static pressure working mode, the gas is supplied by the external gas source 300 (the solenoid valve on the gas source gas circuit A is opened, and the solenoid valve on the gas supply gas circuit B is closed): the pressure of the external gas source 300 After the gas is passed into the buffer tank 200 for buffering, it is distributed to the gas bearing 100 through the buffer tank 200 through the bearing air circuit C;

At this time, since the high-pressure gas provided by the external gas source 300 is several times higher than the standard atmospheric pressure, the gas film of the gas bearing 100 has a certain pressure, and the gas bearing 100 is in a static pressure working state.

Step S2: When the gas bearing 100 is switched from the static pressure working mode to the dynamic pressure working mode, first control the supply air circuit B to open, and the supply air source 400 supplies gas to the buffer tank 200 (control the supply air circuit B on Solenoid valve is open) (the pressure gas from the supplementary gas source 400 is passed into the buffer tank 200 for buffering, and then distributed to the gas bearing 100 through the buffer tank 200 via the bearing gas circuit C), and then the external gas source 300 is controlled to stop the gas supply or control The air source and air circuit A is closed (the external air source 300 is shut down, or the solenoid valve on the air source and air circuit A is closed);

At this time, because the external air source 300 suddenly stops supplying gas, the pressure in the gas path suddenly drops, and the gas in the gas film will flow to the gas path, thereby forming a phenomenon that the gas path draws air from the gas film, resulting in fluctuations in the shape of the gas film, and then Disturb the stability of the working state of the rotor;

However, the setting of the present invention can realize the smooth switching of the gas bearing from the "static pressure working state" to the "dynamic pressure working state", and ensure the stability of the rotor working state: on the one hand, the buffer tank 200 can be Storing relatively more gas to maintain the pressure can weaken the phenomenon of pumping gas from the gas film to a certain extent; Air volume and pressure, and then try to avoid drawing air from the air film, so as to avoid the fluctuation of the air film shape during switching and keep the air film stable.

Step S3: when the gas bearing 100 stops working, the gas is supplied by the external gas source 300, and the gas supply source 400 stops supplying gas;

At this time, the gas bearing is in the static pressure working state. Due to the existence of the buffer tank, the gas film shape of the gas bearing will not fluctuate obviously due to the change of the gas source pressure, so the gas bearing can be guaranteed to stop working smoothly.

Example 3

A micro gas turbine, as shown in Figure 2, includes the gas path system for the gas bearing of embodiment 1, the rotating shaft 1, and the compressor, turbine 3, gas bearing and generator 2 arranged on the rotating shaft 1, wherein, The air compressor is used as the supplementary gas source 400, and the input end of the supplementary air circuit B communicates with the outlet of the compressor.

The gas bearing 100 is a gas bearing group composed of two radial bearings (the first radial bearing 110, the second radial bearing 130) and two thrust bearings 120, as shown in Figure 2; correspondingly, the bearing The gas path C includes three branches: branch gas path I C1, branch gas path II C2 and branch gas path III C3. The branch gas path I C1 communicates with the first radial bearing 110, and the branch gas path II C2 communicates with the thrust The bearing 120 communicates, and the branch air passage III C3 communicates with the second radial bearing 130.

Although the specific implementation of the present invention has been described above in conjunction with the examples, it is not intended to limit the protection scope of the present invention. Those skilled in the art should understand that on the basis of the technical solution of the present invention, those skilled in the art do not need to pay creative work Various modifications or variations that can be made are still within the protection scope of the present invention.

Claims

A gas path system for gas bearings, characterized in that it includes a gas source gas path, a supplementary gas path, a bearing gas path and a buffer tank, wherein the input end of the bearing gas path communicates with the buffer tank, and the output end communicates with the gas Bearing communication;

The input end of the gas source and gas path is connected with the external gas source, and the output end is connected with the buffer tank. The tank supplies gas to the gas bearing;

The input end of the supplementary air circuit is connected with the supplementary gas source, and the output end is connected with the buffer tank. The supplementary air circuit is used to supply the gas bearing through the buffer tank when the gas bearing is switched from the static pressure working mode to the dynamic pressure working mode. gas.
The gas circuit system for gas bearings according to claim 1, wherein the buffer tank is a rigid tank or an elastic tank.
The gas circuit system for gas bearings according to claim 1, characterized in that: a solenoid valve is provided on the gas source gas circuit; a solenoid valve is provided on the gas supply circuit.
The gas circuit system for gas bearings according to claim 1, characterized in that: the external gas source is selected from any one of screw pumps, piston pumps or centrifugal pumps, and the gas supply gas source is selected from screw pumps Either pump, piston pump or centrifugal pump.
The gas circuit system for gas bearings according to claim 1, characterized in that: the external gas source is selected from any one of screw pumps, piston pumps or centrifugal pumps; the gas supply gas source is selected from compressed air machine, and the input end of the air supply circuit communicates with the outlet of the air compressor.
The gas circuit system for gas bearings according to claim 1, characterized in that: the number of the gas bearings is more than two; the gas bearings are radial bearings, thrust bearings or radial bearings with the same air inlet One-piece thrust bearing.
The gas circuit system for a gas bearing according to claim 6, wherein the gas circuit of the bearing includes more than two branches, and the number of branches corresponds to the number of gas bearings.
The gas circuit system for gas bearings according to claim 6, wherein the gas bearing is a gas bearing group composed of two first radial bearings, a second radial bearing and two thrust bearings;

The bearing air path includes three branches: branch air path I, branch air path II, and branch air path III. The branch air path I communicates with the first radial bearing, and the branch air path II communicates with the thrust bearing. The branch air path III communicates with the second radial bearing;

The gas supply source is an air compressor, and the input end of the air supply circuit communicates with the outlet of the air compressor.
The control method for the gas circuit system of the gas bearing according to any one of claims 1 to 8, characterized in that it comprises the following steps:

When the gas bearing is in the static pressure working mode, the gas is supplied by an external gas source: the pressure gas from the external gas source is passed into the buffer tank for buffering, and then distributed to the gas bearing through the buffer tank through the bearing gas circuit;

When the gas bearing is switched from the static pressure working mode to the dynamic pressure working mode, firstly control the opening of the supplementary gas circuit, supply gas from the supplementary gas source to the buffer tank, and then control the external gas source to stop the gas supply or control the gas source to close the gas circuit .
A micro gas turbine, comprising the gas circuit system for gas bearings according to any one of claims 1-8.