The effect of labyrinth seal clearance on stator-well flow and windage heating

Abstract

Due to heat generation arising from turbulence and viscous dissipation of energy in the boundary layer the temperature rises in localised areas in almost any form of rotordynamic machine. Applied to rotating surfaces running in enclosed spaces, this parasitic heating is generally termed 'Windage' heating and it can cause the peripheral metal of a compressor drum to be heated above the usual relative total temperature. This paper presents the result of a CFD validation exercise using the code Star-CD to model the labyrinth seal in an axial compressor stator-well. Agreement with existing labyrinth seal data is good. The detailed effect of labyrinth seal clearance is presented and it is shown that for the typical stator-well geometry chosen an optimum clearance exists. Local values of heat transfer, useful for thermo-mechanical modelling, are presented and details of the various CFD parameters and empirical settings are given.