Startup Performance of Dry Gas Seals with Different Types of Grooves Considering the Slip Flow Effect

Abstract

Finite difference method is used to solve modified Reynolds equation based on FK slip flow model. The startup performance of spiral groove dry gas seal (S-DGS), T-groove dry gas seal (T-DGS) and linear groove dry gas seal (L-DGS) in startup stage are analyzed. The results show that in the startup stage, the slip flow effect reduces the opening force, and the influence of slip flow effect on the opening force is the most obvious for S-DGS, while it is the weakest for L-DGS. Considering the slip flow effect, the hydrodynamic pressure effect of S-DGS is the largest and that of L-DGS is the smallest. Under the same conditions, the shaft speed range of S-DGS with obvious slip flow effect with the Knudsen number being 0.001 is the smallest, and that of T-DGS is the largest. The research provides theoretical guidance for the reasonable evaluation of the influence of slip flow effect on the startup performance of dry gas seals in the startup stage.