An improvement of labyrinth seal in shroud of centrifugal compressor with low flow coefficient

The reverse auxiliary teeth are added in the labyrinth seal of a carbon dioxide centrifugal compressor with low flow coefficient. The influence of the height and installation position of the auxiliary device on the sealing performance is analyzed by three-dimensional viscous numerical simulation. The results show that the sealing performance is greatly improved by adding the reverse auxiliary teeth. When the ratio of height to thickness of the auxiliary tooth is 9, the leakage loss coefficient reduces by 45% compared with the case of basic seal structure. Meanwhile the coefficient decreases of 47.6% as the ratio of offset to thickness is 4.