A Model for Cylindrical Hole Film Cooling—Part I: A Correlation for Jet-Flow With Application to Film Cooling

This paper presents a model to predict the flow structure of cooling flows emanating from cylindrical holes. It is based on a correlation of the flow field with characteristic film cooling parameters. In a previous paper, the authors reported on the dependence of the film-jet on flow parameters, such as blowing ratio, density ratio, free stream Mach number, and turbulence intensity. The present paper extends these results by including the effect of geometry parameters, namely length-to-diameter ratio and inclination angle. All correlations are derived based on a numerical parameter study using a validated 3D-CFD model of a flat plate, scaled to engine conditions. To investigate the effects of the geometry parameters as well as their interaction with the aforementioned flow parameters, a DOE varying all parameters was performed. Results from these numerical investigations are used to correlate the flow-field in the film-jet with the underlying film cooling parameters. The focus of this paper is to demonstrate the predictive capability of the proposed correlations. It provides the basis for a model to simulate film cooling flows in 3D-CFD without meshing the cooling hole geometry, which is presented in the second part of this paper.