کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
655208 1457630 2015 10 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Coherent structures in trailing-edge cooling and the challenge for turbulent heat transfer modelling
ترجمه فارسی عنوان
ساختارهای یکپارچه در خنک شدن لبه های خنک کننده و چالش برای مدل سازی انتقال حرارت آشفته
کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی جریان سیال و فرایندهای انتقال
چکیده انگلیسی
The present paper tests the capability of a standard Reynolds-Averaged Navier-Stokes (RANS) turbulence model for predicting the turbulent heat transfer in a generic trailing-edge situation with a cutback on the pressure side of the blade. The model investigated uses a gradient-diffusion assumption with a scalar turbulent-diffusivity and constant turbulent Prandtl number. High-fidelity Large-Eddy Simulations (LES) were performed for three blowing ratios to provide reliable target data and the mean velocity and eddy viscosity as input for the heat transfer model testing. Reasonably good agreement between the LES and recent experiments was achieved for mean flow and turbulence statistics. The LES yielded coherent structures which were analysed, in particular with respect to their effect on the turbulent heat transfer. For increasing blowing ratio, the LES replicated an also experimentally observed counter-intuitive decrease of the cooling effectiveness caused by the coherent structures becoming stronger. In contrast, the RANS turbulent heat transfer model failed in predicting this behaviour and yielded significantly too high cooling effectiveness. It is shown that the model cannot predict the strong upstream and wall-directed turbulent heat fluxes caused by large coherent structures, which were found to be responsible for the counter-intuitive decrease of the cooling effectiveness.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: International Journal of Heat and Fluid Flow - Volume 51, February 2015, Pages 110-119
نویسندگان
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