Particles will be mixed in journal bearings during operation.In order to investigate the effect of particles on oil film characteristics of journal bearing,based on the theory of fluid lubrication,a mathematical model of the dynamic and static characteristics of hydrodynamic journal bearings considering particles was established.The governing equation was discretized by the finite volume method and the first-order upwind,the discretized equation was solved by SIMPLE algorithm,and the influence of particle content on the bearing capacity and friction of the oil film was analyzed.The dynamic mesh-spring smoothing technology was used to update the volume mesh after the journal moves to solve the dynamic characteristic coefficient of the bearing,and the influence of impurity particles on the dynamic characteristic coefficient was analyzed.Results show that the bearing capacity and friction of the oil film ascend at first and then become stable with the increase of particle content,indicating that the particles can improve the oil film bearing capacity to a certain extent,but also increase the friction.The temperature of the oil film is symmetrically distributed around the oil inlet,and the oil film temperature decreases first and then increases in the axial direction.After considering the effect of particles,the four stiffness coefficients of the oil film all decrease,while the oil film damping coefficients Cxx and Cxy decrease,and Cyx and Cyy increase.