Rotational effects on film cooling performance: Simulation of a louver cooling scheme on a rotating turbine blade

Abstract

Purpose

Numerical simulations were carried out for two cooling schemes, a circular hole and a louver cooling scheme, at the leading edge of a rotor blade in a complete turbine stage.

Design/methodology/approach

Two holes were positioned at the leading edge of a rotating blade, one on the pressure side and the other on the suction side. The methodology was validated with a circular hole case. Numerical results of cooling effectiveness for three blowing ratios at three rotational speeds were successfully obtained. Both blowing ratio and rotating speed of the rotor affect the cooling effectiveness level.

Findings

It was shown that for the circular hole, the blowing ratio is the dominant factor at low blowing ratios and the rotational speed is the dominant factor at high blow ratios when jet is prone to lift off in determining the cooling effectiveness level. For the louver scheme, a higher rotational speed leads to a higher level of cooling effectiveness since jet liftoff is avoided.

Originality/value

There are only a few studies of film cooling on a rotational turbine blade and very few studies of film cooling at the leading edge of a rotating turbine blade in the open literature. The present work presents a challenging CFD case. The analysis of film cooling at the leading edge of an airfoil was presented, which sheds light on the physics of film cooling and should prove helpful to the cooling designs of turbine blades.

Citation

Zhang, C.X. and Hassan, I. (2012), "Rotational effects on film cooling performance: Simulation of a louver cooling scheme on a rotating turbine blade", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 22 No. 5, pp. 622-640. https://doi.org/10.1108/09615531211231271