Flow and heat transfer in cavities between rotor and stator disks

Abstract

The paper discusses the aerodynamic effects in a rotor–stator arrangement where rotor-induced air flow is important in the gap between rotor and housing bases. The rotor is adiabatic whereas the housing surfaces are assumed isothermal. For the case of a closed housing, the empirical correlations available in the literature for the estimate of moment coefficients due to aerodynamic effects under similar geometrical and kinematic conditions are compared with the results of CFD simulations. The numerical results on moment coefficients, mechanical power dissipation, and velocity fields are in satisfactory agreement. In order to evaluate temperature fields and heat fluxes, because no empirical correlations were found for the adiabatic-rotor/isothermal-stator conditions of interest, a semi-empirical model was developed, based on mass and angular momentum balances and the Reynolds analogy. Numerical results and approximate estimates of temperature distribution on the rotor surfaces are in reasonable agreement, also for the case of a housing open to radial flow through the gap.