Turbulent Flow Computations for Turbine Disk Cavity Flows

Abstract

Computational Fluid Dynamics (CFD) plays a key role in the design of rim seals for gas turbines because of the detailed information it can provide about the complex flow in the seal region. However, the fidelity of the computed flow depends strongly on the techniques used to model turbulence. We have performed CFD calculations using several different turbulence models and compared the calculations with data from tests in a water rig at rotational Reynolds numbers of up to 6×105. Calculations were performed using the commercial CFD code, FLUENT™ 4.23 (Fluent, 1990). The turbulence models we used were a full Reynolds Stress Model (RSM) and a k-ε model. The calculated flows were compared to test data using two gross flow measurements: (1) differential pressures measured on the stator face, and (2) directions of the flow measured by dye injection on the stator face. The best agreement with test data was achieved using the RSM. We hypothesize that the RSM is superior to the k-ε turbulence model because of its ability to accurately model the highly anisotropic nature of the turbulence near the rotating turbine disk.