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Film cooling effectiveness in single row of holes: First moment closure modeling | ||
Energy Equipment and Systems | ||
مقاله 2، دوره 1، شماره 1، مهر 2013، صفحه 5-18 اصل مقاله (2.35 M) | ||
نوع مقاله: Research Paper | ||
شناسه دیجیتال (DOI): 10.22059/ees.2013.2737 | ||
نویسنده | ||
Farzad Bazdidi-Tehrani; H. Foroutan; M. Rajabi-Zargarabadi | ||
School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran | ||
چکیده | ||
The present article focuses on the evaluation of 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 employs a time scale that is characteristic of the turbulent momentum field, but also an additional time scale devoted to the turbulent thermal field. The low Reynolds number k — ε turbulence model is combined with a two-equation kθ — εθ heat flux model to simulate the flow and heat transfer in a three-dimensional single row of cylindrical holes 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 span wise distributions of effectiveness are computed 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 taken into consideration. | ||
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