Flow field computation and sealing performance analysis of high-speed micro-grooved pumping seal for new energy vehicles

A micro-grooved pumping seal for electric vehicles was investigated. In this regard, the real gas effect and viscosity were described using the virial and Lucas equations, respectively, and the oil–air ratio was used to determine the equivalent density and viscosity of the two-phase fluid formed in the mixture of the lubricant and air in the seal. The compressible steady-state Reynolds equation was solved using the finite difference method. The pumping mechanisms of the seal and the effects of operating parameters (rotational velocity, oil–air ratio, inlet pressure, and temperature) on the steady-state sealing performance were analysed. The seal produces a significant hydrodynamic effect on the sealing face. The opening force of the seal increases with rotational velocity, oil–air ratio, and inlet pressure. However, the force decreases as temperature increases. The oil–air ratio has the most significant effect on the opening force. The pumping rate first increases and then decreases as the rotational velocity increases. It increases with the oil–air ratio and temperature but decreases as the inlet pressure increases. In particular, the pumping rate reaches a maximum when the rotational velocity or temperature increases to a certain value. This phenomenon requires special attention during seal design. Our results provide input for the design of micro-grooved pumping seals for new energy vehicles.