Numerical investigation on the effect of labyrinth seal configuration on leakage

Labyrinth seals have been widely used in rotating machines. In this paper, labyrinth seals with rectangular tooth used in seawater pump with axial flow distribution were studied. The effects of structure parameters of labyrinth seals on sealing performance were numerically studied by the commercial computational fluid dynamics (CFD) software. The sealing length was considered as a constant, while the cavity width, cavity depth, tooth width and pressure ratio were varied. A large number of models were calculated to study the effects of various variables on leakage of labyrinth seals. Firstly, the results show that the effects of the cavity depth on leakage could be ignored compared with that of the cavity width and sealing length. Secondly, the optimal labyrinth seals with lowest leakage can be obtained with the appropriate values of cavity widths. Furthermore, for a certain pressure ratio, the optimal cavity widths resulting in the lowest leakage were demonstrated to be stable irrespective of the values of cavity depth and sealing length. Finally, increasing pressure ratio gives rise to an increase in the optimal cavity width. It reveals that the higher the pressure ratio is, the longer the cavity width is needed to reduce the leakage.