Numerical simulation of the dry gas seal of a centrifugal compressor

The dynamic features of flow field in three models of the unidirectional and bidirectional grooves of the dry gas seal of a centrifugal compressor are simulated using computational fluid dynamics. The computational domain is the gas film between two rotating and stationary rings and inside the grooves. The seal performance is investigated under different thicknesses. The continuum and Navier-Stokes equations are solved by assuming the ideal gas fluid by using structural and hexagonal cells. The flow is considered laminar. the results include pressure distribution, opening force, leakage, and stiffness of the gas film. First, the unidirectional seal is modeled and the results are compared with the experimental results. The results show that the effects of turbulence can be ignored. In the following, two different geometrical models of the bidirectional grooves are used and the results are compared. The results show that the opening force and stiffness of the gas film in two bidirectional groove models are higher than the unidirectional groove. Also, the leakage values in these two models are reduced compared to the unidirectional groove.