DOI: 10.1615/ICHMT.2009.HeatTransfGasTurbSyst
ISBN Print: 978-1-56700-263-8
FIRST MOMENT CLOSURE MODELING OF FILM COOLING EFFECTIVENESS IN SINGLE ROW OF CYLINDRICAL HOLES
ABSTRAKT
The objective of the present paper is to evaluate a first-moment closure model applicable to film cooling flow and heat transfer computations. The present first-moment closure model consists of a higher level of turbulent heat flux modeling, in which two additional transport equations for temperature variance kθ and its dissipation rate εθ are considered. It not only uses a time scale that is characteristic of the turbulent momentum field, but also an additional time scale dedicated to the turbulent thermal field. The low Reynolds number k−ε turbulence model is combined with a twoequation kθ−εθ heat flux model to simulate the flow and heat transfer in a three-dimensional single row film cooling application. Comparisons with available experimental data show that the two-equation heat flux model improves the over-predictions of center-line film cooling effectiveness caused by the standard simple eddy diffusivity (SED) model with a fixed value of turbulent Prandtl number. This is due to the enhancement of turbulent heat flux components in the first-moment closure simulations. Also, the spanwise distributions of effectiveness are calculated with more accuracy due to better predictions of coolant jet spreading. However, the limitations of first-moment closure due to its isotropic approach should be noted.