Investigation of Transonic Fan Rotor Flows Using an Unstructured Mesh Viscous Flow Solver

Abstract

A three-dimensional viscous flow solver is developed for turbomachinery components using unstructured meshes. The numerical scheme is based on the Roes flux-difference splitting with an explicit Runge-Kutta time integration. A standard k-e turbulence model with a wall function boundary condition is adopted to simulate high Reynolds number viscous flows. To accelerate the convergence to steady state, local time stepping and implicit residual smoothing are applied. The code has been applied to calculate flows through a transonic axial fan rotor operating at near peak effciency and at near stall. Blade-to-blade contour plots are compared with the experimental data to validate the present solver. Calculated Mach number distributions are compared with laser anemometer data within the blade row to quantify the accuracy of the calculations. Details of the flow through the rotor including the tip clearance gap are investigated.