Investigation of the roughness strip effects on the separation-induced transition with the γ- Re _Θt transition model on a high-lift low-pressure turbine rotor blade at steady conditions

Authors

Llobet, J.R., Babajee, J., Arts, T. - von Karman Institute, Rhode Saint Genese, Belgium

Abstract

The investigation of a specific CFD approach for studying the effect of roughness strips mounted on the suction side of a low-pressure turbine (LPT) blade is presented. The tests are carried out using the ONERA CFD code elsA. The test case is a cascade with a high pitch-to-chord ratio (g/c = 0.95) of the widely used T106C high-lift (HL) LPT blade. The Chimera Technique is used to introduce the roughness strips geometry in the mesh. Two different geometries are tested: a “wavy wire” and a “straight wire”. The Langtry & Menter transition model and the Abu-Ghannam & Shaw transition criterion are used, and their suitability for this purpose is assessed. The CFD results are compared with the experimental data obtained at the von Karman Institute (VKI) in the framework of the TATMo and UTAT European programmes. The tests are carried out at an outlet isentropic Reynolds number (Re2,is) ranging from 80000 to 185000, at a constant outlet isentropic Mach number (0.65) and inlet turbulent intensity (0.9%) in order to match the already existing experimental results.