Session: 12-13 Advanced film cooling enabled by additive manufacturing

Paper Number: 128042

128042 - Investigation of the Effects of Geometry Variations on the Performance of an Adjoint Optimized Film Cooling Hole 

In recent studies, a turbine film cooling shaped hole designed by adjoint optimization techniques (X-AOpt) was found to have substantially increased film cooling performance with 70% greater adiabatic effectiveness than a reference 7-7-7 shaped hole. Two aspects of the geometry contribute to the high adiabatic effectiveness levels achieved by the X-AOpt holes: the shape of the internal geometry which improves the diffuser performance, and the external protrusions that generate counter rotating vortices that push the core of the coolant jets towards the wall and spread the coolant laterally.  In this study, insight into the relative importance of these two factors was obtained by testing the performance of a row of X-AOpt holes with the protrusions removed from the external surface.  Experiments were also performed with varying pitch between X-AOpt holes to determine how the hole spacing affects film cooling effectiveness. Results from the tests of X-AOpt holes with external protrusions showed a significant 30% decrease in adiabatic effectiveness compared to the standard X-AOpt holes, but the adiabatic effectiveness was still 45% higher than the reference 7-7-7 holes.  Experiments were also conducted using X-AOpt holes with varying pitch between holes of P/D = 4.0, 5.5, and 7.0.  Results from these experiments showed that a decrease in pitch to P/D = 4.0 provided only a slightly increased adiabatic effectiveness compared to standard P/D = 5.5.  However, increasing the pitch to P/D = 7.0 caused a 33% decrease in adiabatic effectiveness compared to the standard spacing, which is significantly greater than the 23% decrease expected based on superposition analysis.

Presenting Author: Molly Ellinger The University of Texas at Austin

Presenting Author Biography: Molly Ellinger is an aeronautical engineer in the United States Air Force. She received her Bachelor of Science from the U.S. Air Force Academy in 2022 and her master’s from the University of Texas at Austin in 2023 with a focus in Mechanical Engineering, Thermal Fluid Systems. She is currently working at Edwards Air Force Base and preparing to begin Test Pilot School as a Flight Test Engineer.

Authors:

Molly Ellinger The University of Texas at Austin
Elise Flachs The University of Texas at Austin
David Bogard The University of Texas at Austin