Leakage and Rotordynamic Performance of a Semi-Y Labyrinth Seal Structure for Centrifugal Pump Based on Multifrequency Whirl Method

Abstract A semi-Y labyrinth seal (SYLS) is proposed to reduce leakage and enhance the stability of centrifugal pump. The calculation adopts a multifrequency circular whirling model with two-control user-defined functions (UDFs) and the numerical predictions align closely with experimental data for labyrinth seals. Furthermore, the influences of tilt angle, rotation speed, pressure difference, and internal clearance on the leakage performance, rotordynamic coefficients, and sealing stability are investigated. Compared to the traditional interlocking labyrinth seal (ILS) structure, the leakage of the counterflow semi-Y type labyrinth seal (CSYLS) and the downflow semi-Y type labyrinth seal (DSYLS) is reduced by approximately 19.2% and 29.8%, respectively. In addition, the effective damping of the CSYLS structure is approximately 50% greater than that of the conventional ILS structure.