Conjugate Heat Transfer Analysis for Film Cooling Configurations With Different Hole Geometries

Abstract

Secondary flows in the cooling jets are the main reason for the degradation of the cooling performance of a film-cooled blade. The formation of kidney vortices can significantly be reduced for shaped holes instead of cylindrical holes. For the determination of the film cooling heat transfer, the design of a turbine blade relies on the conventional determination of the adiabatic film cooling effectiveness and heat transfer conditions for test configurations. Thus, additional influences by the interaction of fluid flow and heat transfer and influences by additional convective heat transfer cannot be taken into account with sufficient accuracy. Within this paper, calculations of a film-cooled duct wall with application of the adiabatic and a conjugate heat transfer condition have been performed for different configurations with cylindrical and shaped holes. It can be shown that the application of the conjugate calculation method comprises the influence of heat transfer on the velocity field within the cooling film. In particular, the secondary flow velocities are affected by the local heat transfer, which varies significantly depending on the local position.

Effects of chemical reaction caused by cooling stream on film cooling effectiveness

“…The computational results are presented and compared by introducing a non-dimensional parameter-local adiabatic film cooling effectiveness [16], which is defined as:…”

Numerical investigation of the effectiveness of effusion cooling for plane multi-layer systems with different base-materials

“…One of the first to work in this field was Bohn et al [13][14][15]. Bohn et al [16] have furthermore compared the flow field and temperature distribution on a film-cooled turbine blade using both the conjugate technique and adiabatic wall temperatures.…”

Use of CFD for Thermal Coupling in Aeroengine Internal Air Systems Applications

“…Examples of such expanded CFD solvers for the conjugate analysis are NASA Glenn-HT code by Rigby and Lepicovsky (2001), and Aachen's CHTflow solver by Bohn et al (2001). A number of papers have been published showing application of the conjugate analysis for engine component temperature predictions, such as a real turbine rotor-stator system simulation by Okita and Yamawaki (2002), a blade film cooling prediction by Bohn et al (2003) and an internally cooled turbine blade application by Kusterer et al (2004). The latest developments and applications of the conjugate analysis were reported recently by Alizadeh et al (2008) for high pressure (HP) turbine firtrees, Davison et al (2008) for an automated analysis of turbine blade cooling simulation and Okita (2006) for a simple transient simulation of a turbine disc rotor-stator rig.…”

“…These are hereafter referred as conjugate analysis, non-coupled procedure and coupled approach, respectively. A good review on the thermal coupling development was made by Dixon et al in 2004. This was followed by a recent brief discussion on the issue by Chew and Hills in 2007. In the present paper, a more comprehensive review was made with emphasis on the latest progress in the internal air system applications in the recent years.…”