The computational fluid dynamics(CFD) two phase flow and dynamic mesh technologies were applied to the numerical calculation of dynamic characteristics of journal bearing.A new journal bearing dynamic characteristic solving model using the two phase flow theory of CFD model was established.The two phase flow theory of computational fluid dynamics for the journal bearing dynamic characteristics did not need to define the oil film rupture boundary condition

and it can generate more complementary and more accurate flow information.The pressure distribution characteristics of the sliding bearing were compared

and the cavitation characteristics and the effects of the journal bearing were calculated.Finally

the effect of the two phase flow theory of CFD model on dynamic characteristics of journal bearing was analyzed.Calculation results show that the cavitation ratio increases significantly with the increase of rotating speed

eccentricity

and vaporization pressure

and decreases slowly with the increase of inlet pressure.Using two phase flow

calculation results also show that the direct stiffness increases

the cross stiffness decreases and the direct and cross dampings decrease.The deviation between the single phase flow and the two phase flow increases with the increase of eccentricity.