High heat dissipation rate foil type axial thrust bearing, combined bearing and thermal management method

Abstract

In the high heat dissipation rate foil type axial thrust bearing, combined bearing and bearing heat management method described in the present invention, a plane boss is added in the center of the base, and an end surface cooling air groove is added on the boss, and the cooling air groove The number and position of the corrugated elastic foil correspond to the corrugated design and position. On the one hand, the boss provides support for the corrugated elastic foil, which is convenient for processing the cooling air groove on the end surface, and provides convenience for radial cooling of the thrust bearing. On the other hand, The boss increases the clearance between the thrust bearing and the base surface of the combined bearing, providing more options for the design of the cooling flow passage of the entire bearing system. On the one hand, the cooling air groove on the end surface expands the area of ​​the cooling air flow passage, reduces the flow resistance, and increases the cooling gas flow, thereby enhancing the cooling and heat transfer effect on the smooth foil and corrugated elastic foil, and reducing the temperature of the thrust bearing.

Description

technical field [0001] The invention relates to the technical field of thermal management of air foil bearings, in particular to a high heat dissipation rate foil axial thrust bearing, a combined bearing and a thermal management method. Background technique [0002] A fuel cell is a device that directly converts the chemical energy of hydrogen and oxygen into electrical energy through an electrode reaction. Among them, the products after the chemical reaction of hydrogen and oxygen are mainly water and heat. Therefore, fuel cells are considered to be the main source of future automobile power because of their clean properties. At present, the research and application of fuel cells for automobile power mainly focus on proton exchange membrane fuel cells (PEMFC). In the core technology of the fuel cell, the electric stack can be compared to the "heart" of the fuel cell, which is the core of generating electric energy, and the air compressor can be called the "lung" of the fu...

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Problems solved by technology

[0005] (1) It will cause overheating of the material of the corrugated elastic foil 402: the corrugated elastic foil 402 is usually made of nickel-based superalloy Inconel. As the temperature increases, its elastic modulus will decrease, resulting in a softening effect. This softening effect increases the compliance of the foil aerodynamic bearing, thereby reducing the maximum load capacity of the foil aerodynamic bearing; moreover, studies have shown that the stiffness (and possibly damping) characteristics of the foil aerodynamic bearing also will change as a result, which will greatly affect the rotordynamic performance of the system

[0006] (2) It will seriously affect the performance of the top smooth foil 403 coating; in order to reduce the cost of fuel cell air compressors, the foil-type aerodynamic bearings generally use a low-temperature coating with a simple process, and the working temperature of the low-temperature coating is generally It is required to be below 200°C, too high temperature will reduce the performance of the coating, or even fall off

[0007] (3) Foil-type aerodynamic bearings may also produce self-sustaining cycles (that is, thermal runaway), which may lead to serious failures; since the shaft 404 absorbs most of the heat during the operation of the bearing, the expansion speed of the shaft is faster than that of the bearing. Thereby increasing the preload of the bearing, as the bearing preload continues to increase, just like the additional radial load between the shaft 4 and the bearing continues to increase, this will amplify the stress on the fluid film and cause additional Heat generation and further expansion of the shaft, resulting in the appearance of self-sustaining cycles (ie, thermal runaway)

[0008] (4) In the axial direction, the temperature cannot be transmitted in time, and an excessively high axial thermal gradient will be formed from the inside of the foil aerodynamic bearing to the axial edge, and the excessive axial thermal gradient will cause the top smooth foil to produce Distortion, which in turn interferes with the formation of the air film 405 or prevents the formation of the air film 405 completely, which can cause bearing failure at high speeds and / or high load levels

Although some people use forced airflow to pass through the bearing gap to achieve bearing cooling, but because the gap gap is small, the channel flow resistance is large, and the amount of cooling air is too small, the effect is not very obvious

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