Internal Damper Characteristics of Rotor System withSubmerged ER Fluid Journal Bearing

[摘要] Electro-Rheological (ER) fluid behavior is similar to Bingham fluid’ s. Only when the shearstress magnitude of ER fluid exceeds the yield stress, Newtonian flow results. Continuousshear strain rate equation about shear stress which simulates Bingham-like fluid showsviscosity variations. Shear yield stress is controlled by electric fields. Electric fields incircumferential direction around the journal are also changeable because of gap distance.These values make changes of spring and damping coefficients of journal bearings comparedto Newtonian flow case. Implicit viscosity variation effects according to shear strain rates offluid are included in generalized Reynolds' equation for submerged journal bearing. Fluidfilm pressure and perturbation pressures are solved using switch function of Elord's algorithmfor cavitation boundary condition. Spring and damping coefficients are obtained forseveral parameters that determine the characteristics of ER fluids under a certain electricfield. From these values stability region for simple rotor-bearing system is computed. It isfound that there are no big differences in load capacities with the selected electric fieldparameters at low eccentric region and higher electric field can support more load withstability at low eccentric region.

[学科分类] 力学，机械学