Rig tests and computational fluid dynamic (CFD) modelling have been used to improve the understanding of the effects of component geometry and air bleed flows on the pressure and velocity variations in the rotor-stator cavity found typically behind the impeller of a gas turbine engine centrifugal compressor.
Ranges of axial gap ratio and bleed throughflow typical of those found in current gas turbine engine design have been investigated with close attention to radial inflow (centripetal) bleeds with and without initial swirl.
CFD models have been constructed corresponding to the test conditions to assist in the understanding of the test data and to validate the computational methods. These methods can be used to extend the ranges of geometry, rotational Reynolds number and throughflows studied with greater confidence, thereby providing a design tool for direct use in the gas turbine industry.