Wide speed range large load supercritical carbon dioxide dynamic and static pressure tilting pad bearing system

Abstract

The present application relates to air bearing technical field, specifically for wide speed big load supercritical carbon dioxide dynamic pressure tilting pad bearing system, including with supercritical carbon dioxide flow passage's tilting pad bearing, supercritical carbon dioxide gas supply control loop and temperature, pressure acquisition circuit;With supercritical carbon dioxide flow passage's tilting pad bearing includes bearing shell, damper and tile, the tile, damper and bearing shell are sequentially arranged from inside to outside, and tile and damper are respectively fixed on bearing shell.The present application increases damper between bearing tile and bearing shell, effectively improves the damping characteristic and stability of bearing, dynamic pressure mixed lubrication mode improves the lubricating performance under S-CO2 medium, overcomes the defect of static pressure bearing under high speed, significantly improves the comprehensive service performance of bearing, so that it can maintain good lubricating performance and carrying capacity in wide speed range.

Description

Technical Field

[0001] This invention relates to the field of air bearing technology, specifically to a wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system. Background Technology

[0002] In the field of mechanical bearing technology, with the widespread application of supercritical carbon dioxide (S-CO2) as a circulating working fluid in various fields such as solar energy, nuclear energy, and waste heat utilization, higher requirements are placed on bearing performance, making it a high-performance bearing lubricant. Supercritical carbon dioxide is characterized by high density, low viscosity, and strong fluidity, which can reduce compression power consumption and improve circulation efficiency when used as a circulating working fluid. However, during operation, especially under the requirements of high parameters and high performance, supercritical carbon dioxide power units require bearings to meet the requirements of high DN value (shaft speed × bearing inner diameter) and high stability.

[0003] However, in actual use, traditional oil-lubricated bearings are prone to decomposition failure of the lubricating medium in high-temperature environments, and are difficult to adapt to the corrosive and low-viscosity characteristics of supercritical carbon dioxide.

[0004] While gas bearings are suitable for high-speed applications, their load-bearing capacity is limited and cannot meet the demands of high loads.

[0005] Hydrostatic bearings exhibit excellent stability at low speeds, but their hydrodynamic effect is insufficient at high speeds.

[0006] Hydrodynamic bearings rely on rotational speed to form a lubricating film, and boundary friction is prone to occur at low speeds;

[0007] Hybrid bearings combine the advantages of both dynamic and static pressure to some extent, but their dynamic response and load uniformity are still insufficient in supercritical carbon dioxide media.

[0008] Tilting pad bearings can optimize the distribution of lubricating film and improve stability by adaptively adjusting the pads. However, their application research in supercritical carbon dioxide environments is still immature. Existing tilting pad structures are mostly designed for traditional lubricating media and do not fully consider the phase change characteristics, thermodynamic behavior and their impact on the dynamic characteristics of bearing clearance of supercritical fluids. This leads to problems such as lubricating film rupture and local overheating under high-speed and heavy-load conditions. Summary of the Invention

[0009] The purpose of this invention is to provide a wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system to solve the problem that bearings in S-CO2 medium have poor load-bearing capacity and stability, and cannot meet the application requirements of wide speed range and high load-bearing capacity.

[0010] To achieve the above objectives, the present invention provides the following technical solution: a wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system, comprising a tilting pad bearing with a supercritical carbon dioxide flow channel, a supercritical carbon dioxide gas supply control circuit, and a temperature and pressure acquisition circuit.

[0011] The tilting pad bearing with supercritical carbon dioxide flow channels includes a bearing housing, a damper, and pads. The pads, damper, and bearing housing are arranged sequentially from the inside to the outside, and the pads and damper are fixed on the bearing housing. Multiple static pressure supercritical carbon dioxide flow channels are evenly distributed on the bearing housing in the axial and circumferential directions. The inner wall of the pads is provided with air supply holes that communicate with the static pressure supercritical carbon dioxide flow channels, so that static pressure supercritical carbon dioxide is supplied to the rotating shaft inside the pads through the static pressure supercritical carbon dioxide flow channels and air supply holes.

[0012] The temperature and pressure acquisition circuit includes a pressure sensor and a temperature sensor installed at one end of the tile corresponding to the air supply hole, used to collect the pressure and temperature load distribution of the air film at different positions of the gap between the bearing housing and the shaft during the rotation of the shaft.

[0013] The supercritical carbon dioxide supply control loop includes a gas source, a controller, and multiple sets of supercritical carbon dioxide supply regulating valves. The gas source is used to supply static pressure supercritical carbon dioxide into the interior of the static pressure supercritical carbon dioxide flow channel. The supercritical carbon dioxide supply regulating valve is located between the gas source and the corresponding static pressure supercritical carbon dioxide flow channel. The pressure sensor, temperature sensor, and supercritical carbon dioxide supply regulating valve are electrically connected to the controller. The supercritical carbon dioxide supply regulating valve is installed between the output pipeline of the gas source and the static pressure supercritical carbon dioxide flow channel.

[0014] Preferably, the damper is a metal wire mesh.

[0015] Preferably, the number of static pressure supercritical carbon dioxide flow channels is eight, and the eight static pressure supercritical carbon dioxide flow channels are divided into four groups, with two static pressure supercritical carbon dioxide flow channels in each group evenly arranged along the axial direction in the middle of the tile.

[0016] Preferably, the number of pressure sensors and temperature sensors is the same as the number of air supply ports.

[0017] Preferably, the controller is a microcontroller, and the gas source includes one of carbon dioxide and supercritical carbon dioxide.

[0018] Preferably, the controller is used to process and analyze the data on the distribution of air film pressure and temperature load at different positions of the bearing housing and shaft gap during the rotation of the shaft, which are collected in real time by the pressure sensor and temperature sensor, as well as the real-time speed signal and vibration signal of the motor on site, and calculate the corresponding control signal so that the supercritical carbon dioxide supply regulating valve can dynamically adjust the supply pressure and flow rate of each static pressure supercritical carbon dioxide flow channel and its corresponding supply hole according to the controller's instructions.

[0019] Preferably, the supercritical carbon dioxide supply regulating valve includes a pressure reducing valve, a separator, an electro-proportional valve, and a pilot pressure reducing valve. The supercritical carbon dioxide supply regulating valve is used to perform multi-stage pressure regulation of each static pressure supercritical carbon dioxide flow channel.

[0020] Compared with the prior art, the beneficial effects of the present invention are:

[0021] 1. This invention effectively improves the damping characteristics and stability of the bearing by adding a damper between the bearing shell and the bearing housing. The hydrostatic mixed lubrication method improves the lubrication performance under S-CO2 medium, overcomes the defects of hydrostatic bearings at high speeds, and significantly improves the overall service performance of the bearing, enabling it to maintain good lubrication performance and load-bearing capacity over a wide speed range.

[0022] 2. At low speeds, the static pressure effect plays a dominant role in this invention, while at high speeds, the dynamic pressure effect gradually increases, working together with the static pressure to maintain the stable suspension of the bearing. This dynamic-static pressure switching adjustment mechanism allows the bearing to adapt to the needs of different speeds. At the same time, by intelligently adjusting the static pressure supply pressure, this invention can flexibly adjust the bearing stiffness and load-bearing capacity, reducing the consumption of external air sources and achieving significant energy-saving effects. In addition, during high-speed operation, by adjusting the static pressure supply volume and flow rate, the cooling effect of supercritical carbon dioxide is utilized to effectively reduce the operating temperature of the bearing, thereby improving the bearing's durability and stability. Attached Figure Description

[0023] Figure 1 This is a partial exploded view of the overall structure of the wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system of the present invention;

[0024] Figure 2 This is a partial orthogonal sectional view of the overall structure of the wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system of the present invention;

[0025] Figure 3 This is a schematic diagram of the circumferential hydrostatic supercritical carbon dioxide flow channel control loop of the wide speed and high load capacity supercritical carbon dioxide dynamic and static pressure tilting pad bearing system of the present invention;

[0026] Figure 4This is a schematic block diagram illustrating the operation of the wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system of the present invention.

[0027] In the diagram: 1. Bearing housing; 2. Damper; 3. Air supply port; 4. Static pressure supercritical carbon dioxide flow channel; 5. Tile; 6. Pressure sensor; 7. Temperature sensor; 8. Pressure reducing valve; 9. Separator; 10. Electro-proportional valve; 11. Pilot pressure reducing valve. Detailed Implementation

[0028] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0029] Please see Figure 1-4 The present invention provides a technical solution: a wide speed and high load capacity supercritical carbon dioxide dynamic and static pressure tilting pad bearing system, including a tilting pad bearing with a supercritical carbon dioxide flow channel, a supercritical carbon dioxide gas supply control circuit, and a temperature and pressure acquisition circuit.

[0030] A tilting pad bearing with supercritical carbon dioxide flow channels includes a bearing housing 1, a damper 2, and pads 5. The pads 5, damper 2, and bearing housing 1 are arranged sequentially from the inside out and are attached to each other in pairs. The pads 5 and damper 2 are fixed to the bearing housing 1. The damper 2 is a metal mesh. Multiple hydrostatic supercritical carbon dioxide flow channels 4 are distributed axially and circumferentially on the bearing housing 1. The pads 5 are respectively provided with corresponding air supply holes 3 that connect to the hydrostatic supercritical carbon dioxide flow channels 4, allowing hydrostatic supercritical carbon dioxide to be supplied to the rotating shaft inside the pads 5 through the corresponding grouped hydrostatic supercritical carbon dioxide flow channels 4 and air supply holes 3. The hydrostatic supercritical carbon dioxide flow channels 4 can be small air supply holes, throttling holes, porous media materials, or slits, etc., with no structural limitations and no requirement for the number of channels. In this embodiment, the hydrostatic supercritical carbon dioxide flow channels 4 are as follows: Figure 2 As shown, the static pressure supercritical carbon dioxide flow channel 4 adopts a throttling orifice structure. There are eight static pressure supercritical carbon dioxide flow channels 4, and the eight static pressure supercritical carbon dioxide flow channels 4 are divided into four groups. Two static pressure supercritical carbon dioxide flow channels 4 in each group are evenly arranged in the middle of the tile 5 along the axial direction.

[0031] The temperature and pressure acquisition circuit includes a pressure sensor 6 and a temperature sensor 7. A pressure sensor 6 and a temperature sensor 7 are installed at one end of the tile 5 corresponding to the position of the air supply port 3. The pressure sensor 6 and the temperature sensor 7 are distributed on the circumferential and axial inner sides of the tile 5, and are used to collect the pressure and temperature load distribution of the air film at different positions of the gap between the bearing housing 1 and the shaft during the rotation of the shaft, as input data for dynamic and static pressure switching control.

[0032] The supercritical carbon dioxide supply control loop includes a gas source, a controller, and multiple sets of supercritical carbon dioxide supply regulating valves. The static pressure supercritical carbon dioxide entering the static pressure supercritical carbon dioxide flow channel 4 is supplied by an external gas source. The supercritical carbon dioxide supply regulating valve is located between the gas source and the corresponding static pressure supercritical carbon dioxide flow channel 4. During bearing rotation, the controller processes and analyzes the real-time data collected by pressure sensor 6 and temperature sensor 7 on the gas film pressure and temperature load distribution at different positions between the bearing and the shaft during rotor rotation, as well as the real-time speed and vibration signals of the on-site motor, to calculate the corresponding control signals. The supercritical carbon dioxide supply regulating valve dynamically adjusts the supply pressure and flow rate of each static pressure supercritical carbon dioxide flow channel 4 and its corresponding supply port 3 according to the controller's instructions. The controller uses a commonly used microcontroller with no special requirements. The gas source uses carbon dioxide or other supercritical carbon dioxide, such as... Figure 3 As shown, pressure sensor 6, temperature sensor 7, and supercritical carbon dioxide supply regulating valve are electrically connected to the controller. The supercritical carbon dioxide supply regulating valve is installed between the output pipeline of the gas source and the static pressure supercritical carbon dioxide flow channel 4.

[0033] The supercritical carbon dioxide supply regulating valve consists of a pressure reducing valve 8, a separator 9, an electro-proportional valve 10, and a pilot pressure reducing valve 11. The supercritical carbon dioxide supply regulating valve is used to perform multi-stage pressure regulation of each static pressure supercritical carbon dioxide flow channel 4.

[0034] Working principle: such as Figure 4 As shown, the method for switching and adjusting dynamic and static pressure using the tilting pad bearing with supercritical carbon dioxide flow channel of the present invention includes: low-speed static pressure dominance, high-speed dynamic pressure dominance, high-speed static pressure heat dissipation, and high-speed static pressure stiffness adjustment.

[0035] During operation, the bearing's supporting pressure is:

[0036] P 总 =P 静 +P 动

[0037] In the formula, P 总 This represents the total weight of the rotor and the external load, i.e., the bearing load; P 静 P represents the bearing air buoyancy component caused by the internal hydrostatic pressure effect;动 This represents the bearing air buoyancy component caused by the dynamic pressure effect when the journal rotates;

[0038] in,

[0039] Low-speed static pressure dominant: When the journal speed is lower than the takeoff speed, the supercritical carbon dioxide supply control circuit provides high-pressure, high-flow-rate compressed supercritical carbon dioxide to the bearing through the static pressure supercritical carbon dioxide flow channel 4 and the air supply hole 3. Under the main action of external static pressure, the bearing is lifted by the air film and separated from the shaft, and is in a suspended state.

[0040] High-speed dynamic pressure dominance: As the journal speed increases, the pressure of the dynamic pressure air film formed between the bearing and the journal increases. At this time, the supercritical carbon dioxide supply control circuit gradually reduces the supply pressure of each static pressure supercritical carbon dioxide flow channel 4 and supply hole 3, so that the bearing remains suspended under the main action of dynamic pressure.

[0041] High-speed static pressure heat dissipation: When the journal speed reaches or exceeds the dynamic pressure take-off speed, the static pressure drops to a lower level. At this time, according to the bearing air film temperature distribution detected by the temperature sensor 7, the supercritical carbon dioxide supply control circuit adjusts the air supply of each static pressure supercritical carbon dioxide flow channel 4 and air supply hole 3, so that the supercritical carbon dioxide can carry away some heat and play a role in heat dissipation.

[0042] High-speed static pressure stiffness adjustment: At this time, in order to achieve the design stiffness and load-bearing capacity of the bearing, the supercritical carbon dioxide supply control circuit dynamically adjusts the supply pressure and flow rate of each static pressure supercritical carbon dioxide flow channel 4 and supply hole 3 according to the signals of temperature sensor 7 and pressure sensor 6 and vibration signal. By enhancing or weakening the static pressure effect of supercritical carbon dioxide, the stiffness and load-bearing capacity of the bearing are adjusted.

[0043] This invention, based on tilting pad bearings and incorporating the characteristics of hydrostatic bearings, adds hydrostatic supercritical carbon dioxide flow channels 4 in the axial and circumferential directions of the tilting pad bearing to connect to an external air source. Through a supercritical carbon dioxide supply control loop, the supply pressure and flow rate are intelligently adjusted, relying on the combined effects of supercritical carbon dioxide hydrostatic and dynamic pressure to support the load. At low or zero speeds, the external air source outputs high-pressure, high-flow-rate supercritical carbon dioxide through the supercritical carbon dioxide supply control system, utilizing the hydrostatic effect to maintain the bearing in a suspended state even at low speeds. As the speed increases, the dynamic pressure of the bearing increases, reducing the dependence on the hydrostatic air source. Therefore, the supercritical carbon dioxide supply control system adaptively reduces the output pressure and flow rate of the hydrostatic air supply system, reducing consumption of the external air source. Furthermore, the small flow rate of supercritical carbon dioxide provided effectively cools the bearing, improving the stability, durability, and energy efficiency of the tilting pad bearing. In addition, this invention, through intelligent adjustment of the hydrostatic supply pressure, can flexibly increase or decrease the stiffness and load-bearing capacity of the tilting pad bearing.

[0044] The present invention adds a damper 2 made of metal wire mesh between the tile 5 and the bearing housing 1, which increases the damping coefficient of the bearing, improves the stability of the bearing, and combines the working characteristics of dynamic pressure bearing and static pressure bearing. During operation, its support pressure is the sum of the static pressure provided by the external air source and the dynamic pressure generated by its own rotation.

[0045] When the rotor speed is low or zero, the external gas source outputs high-pressure, high-flow-rate supercritical carbon dioxide through the supercritical carbon dioxide supply control circuit, and the bearing separates from the shaft under the main action of the hydrostatic effect.

[0046] As the rotor speed gradually increases, the dynamic pressure of the bearing itself also gradually increases, reducing its dependence on the static pressure air source. The supercritical carbon dioxide supply control circuit then adaptively reduces the pressure and flow rate of each air supply hole, reducing the consumption of external air sources. This allows the bearing to continue to maintain its suspended state by relying on the static and dynamic pressure effects of supercritical carbon dioxide. At the same time, the small flow rate of supercritical carbon dioxide provided by the external air source can effectively cool the bearing.

[0047] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0048] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system, characterized in that: It includes a tilting pad bearing with a supercritical carbon dioxide flow channel, a supercritical carbon dioxide gas supply control circuit, and a temperature and pressure acquisition circuit. The tilting pad bearing with supercritical carbon dioxide flow channels includes a bearing housing (1), a damper (2), and pads (5). The pads (5), damper (2), and bearing housing (1) are arranged sequentially from the inside to the outside, and the pads (5) and damper (2) are fixed on the bearing housing (1). Multiple static pressure supercritical carbon dioxide flow channels (4) are evenly distributed on the bearing housing (1) in the axial and circumferential directions. The inner wall of the pads (5) is provided with air supply holes (3) that are connected to the static pressure supercritical carbon dioxide flow channels (4) so ​​that the static pressure supercritical carbon dioxide is supplied to the rotating shaft inside the pads (5) through the static pressure supercritical carbon dioxide flow channels (4) and the air supply holes (3). The temperature and pressure acquisition circuit includes a pressure sensor (6) and a temperature sensor (7) set at one end of the tile (5) corresponding to the air supply hole (3), which are used to collect the pressure and temperature load distribution of the air film at different positions of the bearing housing (1) and the shaft during the rotation of the shaft; The supercritical carbon dioxide supply control circuit includes a gas source, a controller, and multiple sets of supercritical carbon dioxide supply regulating valves. The gas source is used to supply static pressure supercritical carbon dioxide into the interior of the static pressure supercritical carbon dioxide flow channel (4). The supercritical carbon dioxide supply regulating valve is located between the gas source and the corresponding static pressure supercritical carbon dioxide flow channel (4). The pressure sensor (6), temperature sensor (7), and supercritical carbon dioxide supply regulating valve are electrically connected to the controller. The supercritical carbon dioxide supply regulating valve is installed between the output pipeline of the gas source and the static pressure supercritical carbon dioxide flow channel (4).

2. The wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system according to claim 1, characterized in that: The damper (2) is a metal wire mesh.

3. The wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system according to claim 1, characterized in that: The number of static pressure supercritical carbon dioxide flow channels (4) is eight, and the eight static pressure supercritical carbon dioxide flow channels (4) are divided into four groups, with two static pressure supercritical carbon dioxide flow channels (4) in each group evenly arranged in the middle of the tile (5) along the axial direction.

4. The wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system according to claim 1, characterized in that: The number of pressure sensors (6) and temperature sensors (7) is the same as the number of air supply ports (3).

5. The wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system according to claim 1, characterized in that: The controller is a microcontroller, and the gas source includes either carbon dioxide or supercritical carbon dioxide.

6. The wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system according to claim 1, characterized in that: The controller is used to process and analyze the data on the distribution of air film pressure and temperature load at different positions between the bearing housing (1) and the shaft during the rotation of the shaft, which are collected in real time by the pressure sensor (6) and the temperature sensor (7), as well as the real-time speed signal and vibration signal of the motor on site, and calculate the corresponding control signal so that the supercritical carbon dioxide supply regulating valve can dynamically adjust the supply pressure and flow rate of each static pressure supercritical carbon dioxide flow channel (4) and its corresponding supply hole (3) according to the controller's instructions.

7. The wide-speed, high-load supercritical carbon dioxide hydrostatic pressure tilting pad bearing system according to claim 1, characterized in that: The supercritical carbon dioxide supply regulating valve includes a pressure reducing valve (8), a separator (9), an electro-proportional valve (10), and a pilot pressure reducing valve (11). The supercritical carbon dioxide supply regulating valve is used to perform multi-stage pressure regulation on each static pressure supercritical carbon dioxide flow channel (4).

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