CFD STUDIES ON SMOOTH AND ROUGH AIRFOIL SURFACES AND THEIR EFFECTS ON LAMINAR TURBULENT TRANSITION AND HEAT TRANSFER

Aerothermal investigations to study heat transfer and transition on a prismatic LPT stator vane were carried out to analyse the effect of different roughness levels. The purpose of these investigations is to improve the understanding of the effect of roughness on the heat transfer and on the reactivity of the transition model. The equivalent sand grain roughness is used to define the roughness on the wall. To take roughness into account with transition, the geometrical roughness is added into the transition model correlation. The study will focus on the heat transfer coefficient of a 2D LPT stator vane. Different Reynolds number and turbulence levels were imposed at the inlet, as well as different surface roughnesses on the airfoil surface. The general objective is to improve the validation and the calibration of CFD models (ANSYS CFX) and more particularly the roughness effect on the transition correlation based on experimental data. The qualitative comparison shows good agreement between computation and experiments. Predicted heat transfer shows good agreement on the pressure side and leading edge. On the suction side, particularly for the transition, a higher reactivity of the model than the measured data was observed.