Dimensional analysis of the working condition dependence on the leakage performance of a hole diaphragm labyrinth seal

Labyrinth seal (LS) is widely used to reduce the leakage of working media. A relatively new kind of labyrinth seal, the hole diaphragm labyrinth seal (HDLS), was studied to obtain lower leakage performance. The dimensional analysis method was used to establish the mathematical model of the HDLS. The analyses of the relationship between different operating conditions and leakage performance were performed by the computational fluid dynamics (CFD) method. Subsequently, the descriptive equation of HDLS under different working conditions was proposed with structural parameters inconsiderate. The validation of this equation shows the relative accuracy, which can be used to predict the leakage performance of the hole diaphragm labyrinth seal. Further validations were performed not only in HDLS but also in two other labyrinth-type seals. The results show that the error between the calculation result in this paper and previous experimental results in the stepped labyrinth seal was 4.37%. Such an error in the damper seal becomes 2.73% lower than the previous prediction. Discussions in this paper showed a bright prospect on structural parameters model establishment by dimensionless analysis method on studies in steam and gas turbine areas.