Film cooling effectiveness in single row of holes:First moment closure modeling
سال انتشار: 1392
نوع سند: مقاله ژورنالی
زبان: انگلیسی
مشاهده: 582
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شناسه ملی سند علمی:
JR_EES-1-1_001
تاریخ نمایه سازی: 28 شهریور 1395
چکیده مقاله:
The present article focuses on the evaluation of a first-moment closure modelapplicable to film cooling flow and heat transfer computations. The present firstmomentclosure model consists of a higher level of turbulent heat flux modeling inwhich two additional transport equations for temperature variance kθ and itsdissipation rate εθ are considered. It not only employs a time scale that ischaracteristic of the turbulent momentum field, but also an additional time scaledevoted to the turbulent thermal field. The low Reynolds number k-ε turbulencemodel is combined with a two-equation kθ-εθ heat flux model to simulate the flow andheat transfer in a three-dimensional single row of cylindrical holes film coolingapplication. Comparisons with available experimental data show that the twoequationheat flux model improves the over-predictions of center-line film coolingeffectiveness caused by the standard simple eddy diffusivity (SED) model with a fixedvalue of turbulent Prandtl number. This is due to the enhancement of turbulent heatflux components in the first-moment closure simulations. Also, the span wisedistributions of effectiveness are computed with more accuracy due to betterpredictions of coolant jet spreading. However, the limitations of first-moment closuredue to its isotropic approach should be taken into consideration
کلیدواژه ها:
Film Cooling ، First-Moment Closure ، Two-Equation kθ-εθ Heat Flux Model ، Turbulent Heat Flux Modeling
نویسندگان
f Bazdidi-Tehrani
School of Mechanical Engineering Iran University of Science and Technology, Tehran 16846-13114, Iran