Simulation of Subsonic Flow Through a Generic Labyrinth Seal

Abstract

A new method for predicting the leakage through labyrinth seals has been developed and is shown to provide realistic results which agree with measurements. It utilizes a finite-difference computer code which was developed in order to compute the pressure drop across a single cavity of the seal. This quantity is obtained at several leakage flow Mach numbers to be used subsequently in predicting the leakage rate. The model is widely applicable and does not require an estimate of the kinetic energy carry-over coefficient, whose value is often uncertain for many untested configurations. Detailed cavity distributions of basic flowfield quantities are also presented and examined. Specifically, the predicted results of four seal leakage mass flow rates at given cavity inlet pressure and temperature are compared, and important variations are examined. Also, realistic approximations of flow variable distributions within a single cavity are made from the included figures to assist in the development of analytical methods.