报告题目：Large-Eddy Simulations of Turbine Blade Internal Cooling  Two-Pass Duct with Ribs 
报告地点：北二楼1402 
报告时间：2017年7月23日上午9:00
报告人：Danesh Tafti教授
报告摘要： 
Accurate prediction of turbine blade internal cooling is a critical component in the overall design of cooling systems for high temperature first stage HP blades. To increase the heat transfer coefficient, a variety of augmentation surfaces are used consisting of normal or angular ribs, pin fins, dimples, protrusions, combined together or with flow impingement jets in critical regions. The flows encountered are highly turbulent with non-equilibrium effects such as separation and reattachment, strong secondary flows, secondary strains induced by rotation and buoyancy forces, streamline curvature and other non-canonical effects, which make the accurate prediction of heat transfer coefficients a challenge. Reynolds Averaged Navier-Stokes (RANS) are most commonly used to predict the heat transfer coefficient, however, because of the flow complexity these class of models are unable to produce consistent, repeatable and robust predictions. On the other hand, unsteady methods based on Large-Eddy Simulations, which resolve a large part of the turbulent spectrum, are more repeatable and robust in prediction accuracy. However, the grid resolution requirements of these methods increases exponentially as the Reynolds number increases.  The lecture will show results from recent work in the application of Large-Eddy Simulations to a two-pass duct with staggered normal ribs under the influence of rotation at high Reynolds number.  The numerical method and models will be described with flow and heat transfer results. Additionally, some ideas for the future of blade heat transfer predictions will be discussed.