Abstract: In the process of forming hydrodynamic pressure, it is necessary for fluid-wedge and non-contacting mechanical seal to prepare for an auxiliary systems to provide a clean blocking fluid, which is aimed to prevent damage to the sealing end face by solid particle in the fluid. For the pump-out self-pumping fluid dynamic mechanical seal, the self-cleaning characteristics with particle diameter, rotation speed, pressure, liquid film thickness and particle volume concentration were studied by using the DPM model and the Laminar model in Fluent. The results show that the increase of volume concentration decreased the particle chip removal rate. As the particle volume concentration was low enough, the chip removal rate was hiigher than 60%. As the particle diameter increased, the chip removal rate firstly increased and then decreased. When the diameter was 0.7 μm, the chip removal was up to 79.35%. As the rotation speed increased, the chip removal rate decreased firstly and then increased significantly. The chip removal rate was 94% in the calculated range of 0~6 000 r/min. The seal pressure difference and the liquid film thickness had no obvious effect on particle chip removal rate