Computational Simulation of Turbulent Endwall Effects in Gas Turbines, Using LES Approach<br/>

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Computational Simulation of Turbulent Endwall Effects in Gas Turbines, Using LES Approach

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Type of Document: M.Sc. Thesis
Language: Farsi
Document No: 42729 (45)
University: Sharif University of Technology
Department: Aerospace Engineering
Advisor(s): Tayyebi Rahni, Mohammad; Ramezanizadeh, Mahdi
Abstract:
The most common three-dimensional flows accuring in axial turbomachineries are endwall flows. These flows, which depend on inner hub and on external surface of airfoils are called secondary flows. In modern turbines, these flows reduce turbine efficiency up to about 3 percent.Many sientists are interested in investigation such flows. In this study, turbulent endwall flows are modeled using large eddy simulation approach. Also, SIMPLE algoritm and Smagorinsky subgrid scale model are used. Non-orthogonal curvilinear coordinate system and structural grid are implemented.To verify the results, they were compared with some existing experimental data which, showed that current numerical results has a relatively good coorolation with the experimental ones.The results of two diffrenet Reynoulds numbers show that the pressure surface vortex is separated from the surface and moves into the blade suction surface because of the spanwise flow between the baldes. This causes the pressure surface vortex penetration into the suction side vortex
Keywords:
Gas Turbines ; Secondary Flow ; Large Eddy Simulation (LES) ; Smagorinsky Model ; Turbulence Flow Simulation ; Endwall Flows

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