نوع مقاله : مقاله پژوهشی
نویسندگان
ایرانی
چکیده
عنوان مقاله [English]
نویسندگان [English]
The present study numerically assesses two and three dimensionally, of the flow pattern inside channels and around impulse blades of a supersonic turbine. Also the effects of edge-sharpening on the aerodynamics of blades have been of concern. Primary studies show that with geometric modification of blades, optimization of the efficiency of turbine is possible. The numerical and experimental results suggest that edge-sharpening modifies flow pattern and improves shock field on the area between nozzle and. Supersonic turbines do not need cooling system and their flow is of compressible, supersonic, highly turbulent and complex flow field type. Turbulence flows may have different oscillating velocity fields. Since these oscillations may be very small and haveing a high frequency, their direct simulation will be too costly in regard to practical engineering computations. In numerical studies, correct simulation and the proper turbulence model selection for these flows are very important in obtaining reliable results in reasonable amount of time. The Two turbulence models, and , have been widely used for the numerical analysis of these turbo machines. The present study also aimed to comparatively assess the two models to determine which one is superior for the simulations of impulse turbines. Accurate measurements of the mean characteristics and oscillating of the velocity field have been carried out in boundary layers with . The results of the computations have been compared to those of the experimental analysis.
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