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.