Hydrostatic and hydrodynamic characteristic analysis of three-wedge gas bearing
A three-wedge gas bearing,with both hydrostatic and hydrodynamic pressure characteristics,was specially designed for the bearing-rotor system of the air compressor in hydrogen fuel cell vehicle.The mechanism of hydrostatic and hydrodynamic coupling effect,the flow field characteristics,and the dynamic and static parameters of the bearing were investigated.These results were also compared with those of traditional cylindrical gas bearings.To analyze the flow field characteristics of the bearing,a dynamic mesh program was developed using UDF in Fluent software,and a related CFD transient simulation method was proposed to solve the nonlinear gas film forces and the dynamic parameters of the bearing at any eccentric journal position.The analysis showed that the hydrodynamic and hydrostatic pressure effect intensity of the three-wedge bearing varied with the external working condition,but kept on coupling with each other,ensuring that the bearing always provided effective and stable support for the rotor.At low rotational speed,the hydrostatic pressure effect was the main factor affecting bearing performance,and the three-wedge gas bearing exhibited similar working performance to cylindrical bearing.The three-wedge gas bearing can thus provide stable support for on-board compressor rotor during start-stop and acceleration.With the increase of the rotational speed,the hydrodynamic pressure effect of the three-wedge gas bearing was significantly enhanced.The three-wedge gas bearing can thus provide support for high-speed compressors with lower gas supply pressure than the cylindrical bearing.Therefore,compared with the traditional cylindrical gas bearing that required external gas sources,the three-wedge gas bearing can provide a stable support for the rotor only using the internal gas circuit of the hydrogen fuel cell vehicle.It adapted well with the working environment inside the hydrogen fuel cell vehicle where the gas supply pressure was limited,and the rotor underwent frequent start-stop and speed changes.
gas bearinghydrostatic and hydrodynamic pressure coupling effectdynamic pressure effectbearing characteristicshydrogen fuel cell vehicle
NETL
NSTL
万方数据
