Comparison of experiments and simulations of thermal characteristics of a bearing-rotor system

The hydrostatic spindle system is the main internal heat source of the machine tool, thus it is very significant to study the thermal behaviors of the hydrostatic spindle system. The purpose of this study is to investigate the effect of viscosity-temperature effect of lubricant on the temperature fields of hydrostatic bearing oil film and spindle thermal deformation. To study the effect of temperature rise of hydrostatic bearing oil film on the hydrostatic spindle and bearing bush, empirical equations, CFD, and experimental methods are used in this paper. Firstly, the temperature rise of hydrostatic bearing is obtained by the theoretical calculation method. Secondly, based on the CFD, the temperature field of lubricating oil film is compared and analyzed with consideration of viscous temperature effect and constant value of viscosity. Based on the fluid-thermal-solid coupling method, the thermal deformation of the spindle is analyzed. Finally, the experimental platform of the hydrostatic spindle is built and the accuracy of the simulation results was verified. The study shows that when the viscosity-temperature effect is considered, the values of oil film temperature rise and spindle thermal deformation are closer to the experimental values, and the error rates of bearing temperature and spindle thermal deformation are smaller than those when the viscosity is fixed.