The three dimensional numerical model for a typical labyrinth seal was built to investigate the influence of pressure ratio

seal clearance

tooth width and step height on leakage characteristics of the seal.The results show that

the seal leakage increases with the pressure ratio and the increase rate gradually decreases.The dimensionless parameter j

which is defined as the ratio of tooth width to clearance

can be used to evaluate the flow characteristics in the labyrinth seal.When j≥1

the effect of φ on the flow characteristics in the labyrinth seal is negligible and the seal leakage is proportional to the leakage area.However

when j 1

the variation of j will cause the flow characteristics in the labyrinth seal change dramatically.It means that the effect of j should be considered in the calculation of labyrinth seal leakage.When the step height H_s equals to 0

the labyrinth seal becomes a smooth configuration

which leads to an increase in the seal leakage by above 43%.Therefore

it is not advised to use the labyrinth seal when the axis face is smooth.