Modeling of the slip flow in the spiral grooves of a molecular pump

A rectangular model was proposed to investigate the slip flow in spiral grooves of a molecular pump. Finite volume method was used to integrate the equations over each computational control volume in order to discretize the governing equations. The velocity plots in transverse planes for the rectangular model were presented to illustrate the flow structures. Analysis suggested that slip condition led to weaker reverse flow in the channel and lower compression ratio. The diffusion of circumferential shear stress in radial direction was found to be responsible for the pressure gradient in circumferential direction.