波箔气体轴承温度场计算与动静态性能分析

为计算波箔轴承的温度场分布,研究轴承的热特性,推导了考虑外部冷却条件时的平箔片内表面等效对流换热系数,将箔片一侧的导热换热模型耦合到气膜三维能量传递模型中.建立轴承套、转子的导热与对流换热模型,耦合求解非等温Reynolds方程、气膜能量传递方程、箔片变形方程.计算并分析轴承转速、载荷、外部冷却气流等因素对轴承温度的影响,分析了轴承的静动态性能.结果表明:转速对轴承温度影响很大,温度随载荷变化不大,冷却空气的冷却效率随流量增大逐渐降低.与等温条件相比,非等温模型的轴承承载能力较大,且具有较大的动态刚度与阻尼.

Temperature calculation and static and dynamic characteristics analysis of bump foil gas bearing

To calculate the temperature field of bump foil gas bearing, and to analyze its thermal characteristics, considering outer cooling condition and specific foil structure, the equivalent heat convective coefficient on the inner side of top foil is derived, and the heat conductive and convective models of bearing sleeve and rotor are established respectively. Non-isothermal Reynolds equation, energy transfer equation of gas film and foil deflection equation are solved. The influences of bearing load, out cooling condition, bearing speed, etc. on bearing temperature are finally obtained, and the static and dynamic performance of the bearing is calculated. The results indicate that the bearing temperature is very sensitive to the bearing speed, and the cooling efficiency of the out cooling flow becomes weak with the increase of the cooling mass flow rate. The smaller nominal clearance plays a more important role in influencing the bearing temperature than the larger one. In addition, with the temperature effects considered, the bearing will achieve higher load capacity, larger dynamic stiffness and damping coefficients.