Distinguished Seminar: Sumanta Acharya
August 5, 2015
Gas Turbine Blade Cooling: Using Fundamental Physics for Improved Cooling Design
Friday, Sept. 18, 2015, 3:00 pm
Sidney & Marian Green Classroom
(3550 MEK-Mechanical Engineering Kennecott Bldg.)
Reception to follow at 4:00 pm
Sumanta Acharya, Ph.D.
Ring Companies Chair & Department Chair
Mechanical Engineering Department
University of Memphis, TN
Abstract: Gas turbine components downstream of the combustor are exposed to high temperature gases in excess of 1600 degrees Celsius and have to be cooled to maintain material temperatures below the reliability limit. In film cooling, coolant flow is injected through inclined holes on the airfoil and end-wall surfaces with the intent of providing a protective coolant film over the metal surfaces. The coolant jets however rapidly mix with the hot cross-flow and loose their surface coverage. Different strategies for keeping the coolant jet close to the surface and reducing mixing have been explored. These include diffusing the holes in the forward and/or lateral directions, introducing pulsations and shaping the hole-exit via trenches and craters.
In this talk, the flow physics of the film cooling jet injected into a hot cross-flow will be discussed using high fidelity numerical calculations (e.g., Large Eddy Simulations). Flow structures associated with the coolant jet (e.g., the horseshoe vortex structures, the kidney pair vortex, the shear layer vortices etc.) will be delineated and the mechanisms associated with their origin and evolution discussed. The energetic modes that contribute to the cooling of the surface are identified and analyzed to guide new hole-exit shape designs with improved cooling effectiveness. The important role of inlet turbulence and boundary condition variability will be presented and discussed in light of how a turbine designer may consider these effects.
Bio: Sumanta Acharya is currently the Department Chair of Mechanical Engineering and the Ring Companies Endowed Chair at the Herff College of Engineering, University of Memphis. From 2010-2014, he served as the Program Director of the Thermal Transport Program in the Directorate of Engineering at the National Science Foundation (NSF). The majority of his prior academic career was at Louisiana State University (LSU) where he was the L. R. Daniel Professor and the Fritz & Francis Blumer Professor in the Department of Mechanical Engineering (ME). He was the founding Director (in 2003) of the Center for Turbine Innovation and Energy Research (TIER) which focuses on energy generation and propulsion research. His scholarly contributions include mentoring nearly 85 post-doctoral researchers and graduate students, and publishing nearly 200 refereed journal articles and book chapters and over 230 refereed conference/proceedings papers. Prof. Acharya’s research has been continuously supported by federal funding agencies and industries with nearly 25 million dollars of funded research. Professor Acharya was awarded the 2015 AIAA Thermophysics Award, the 2014 AIChE Donald Q. Kern Award, the 75th ASME Heat Transfer Division Medal (in 2013), and the 2011 ASME Heat Transfer Memorial Award in the Science category. In the area of teaching, Professor Acharya has been selected for the best teacher award by the students on three different occasions.
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