A study on the rotational effect of a stepped labyrinth seal according to the casing type

This paper presents the leakage characteristics of stepped labyrinth seals, considering the impact of rotation in the circumferential direction. Two types of casing, honeycomb and solid lands, were applied to the labyrinth seal, and a numerical study was performed with a wide operating range of the rotational speed, pressure ratio and clearance. The effect of the rotational speed on the sealing performance was analyzed for each clearance size through a parametric study. Regardless of the casing type, the flow function decreased as the rotational speed increased, and the smaller the clearance was, the more the leakage performance was affected by the rotation effect. In particular, it was confirmed that the honeycomb seal had a stronger tendency to decrease the flow function due to the rotation than the solid seal. The honeycomb seal allowed a larger leakage flow in comparison to the solid seal, and the rotational speed played an important role when the clearance was small or moderate. However, when the clearance became large, the leakage flow of the two seal types became almost the same, and the rotational effect became marginal.