Effects of Coolant Air Inlet Conditions on Turbulent Flow Between a Turbine Disk and its Casing

An integral method to predict the performance of the incompressible, turbulent flow between a rotating disk and a parallel stationary wall, when there is radial outflow of ventilation air, is presented. Using this method, the effects of the inlet conditions of the ventilation air on the core rotation, on the radial velocity profile development, on the radial inflow rates, on the separation streamlines between outflow and inflow regions and on the disk torque coefficient are calculated and presented. The method is general enough to calculate other effects. The important conclusions are: (a) that inlet radial velocity profile should be skewed toward the stationary wall, to reduce radial inflow, and (b) that disk friction can be decreased by increasing the rotation of the ventilation air.