带有限制层的多孔质静压气体轴承温度特性分析

Thermal Characteristic Analysis of Aerostatic Porous Journal Bearings with Surface-restricted Layer

多孔质气体轴承越来越多地应用在超高速、超精密的旋转设备中。当轴承在高速重载的环境下工作时,气膜的温升会对轴承性能产生很大的影响。对含有限制层的多孔质静压气体轴承的温度特性进行研究,通过求解雷诺方程得到轴承气压分布,结合能量方程和热传导方程预测轴承的温度场分布。计算结果表明,转轴在高速转动时,气膜会产生较大的温升;当载荷越大、转速越高、轴承间隙越小时,气膜的温度越高;轴承间隙较小时,其最高气膜温度随载荷的增加变化较小。相比于载荷对温升的影响,转速对温升的影响更为明显。同时温升易使转轴产生热膨胀,且热膨胀量随转轴壁厚的增加而增加。与不考虑转轴的热膨胀变形相比,考虑转轴的热膨胀变形时,最小气膜厚度变小,最大气膜压力变大。

Porous gas bearings have been successfully used in high speed rotating machinery and precision devices. When the bearing operates at high speed and heavy load, the temperature rise of gas film would influence the bearing performance significantly. Therefore, the temperature characteristics of the aerostatic porous journal bearing with a surface-restricted layer will be studied. The pressure distribution of the film is calculated by using the Reynolds Equation, and then the temperature field distribution is predicted by coupling the energy equation and heat conduction equation. The results indicate that the temperature of the film increases significantly at high speed. The film temperature increases as load increases, speed increases or bearing clearance decreases. when the bearing clearance is small, the highest temperature of gas film increases little as load increases. Compared with the influence of the load, the speed have more significant impact on the film temperature. Moreover, the thermal deformation of the rotor increases as the thickness of the hollow shaft increases. The predictions indicate that the maximum gas pressure increases and the minimum film thickness decreases when considering the thermal deformation of the rotor.