Session: 12-14 Film cooling computational studies

Submission Number: 177908

Numerical Analysis of Streamwise and Spanwise Hole Spacing Effects on the Thermal and Hydrodynamic Behaviour of Effusion-Cooled Plates 

This study numerically investigates the effects of streamwise and spanwise hole spacing in effusion cooling schemes using cylindrical holes with 90° injection. A total of five configurations were examined by varying the pitches independently. The cooling performance of all configurations was evaluated through contours and localized plots of film cooling effectiveness, along with velocity profiles and TKE contours. The results show that varying the streamwise pitch did not affect the area averaged film cooling effectiveness. This indicated that streamwise pitch redistributes coolant rather than altering the overall cooling performance. Reducing the spanwise pitch significantly enhanced lateral jet superposition. However, concentrating the hole array around the centerline did not yield optimal global cooling. Normalized exit velocity profiles showed that local blowing ratios varied along the array, with exit velocities increasing downstream for the baseline. Velocity and turbulence kinetic energy analyses demonstrated that coolant jets are injected nearly perpendicular to the surface, resulting in repeated detachment and reattachment processes that generate counter-rotating vortex pairs. Lateral mixing, rather than streamwise interaction, was shown to be the dominant mechanism responsible for filling spanwise gaps and extending the cooling film. Within the investigated range, the optimal streamwise pitch was 2.15 D; its configuration provided effective coolant coverage with reduced pressure losses. The optimal spanwise pitch was 1.79 D as it achieved a balance between lateral coolant interaction and uniform surface coverage.

Presenting Author: Omar Aly Texas A&M University

Presenting Author Biography: Omar Aly is a PhD candidate in Mechanical Engineering at Texas A&M University at Qatar, under the supervision of Dr. Ibrahim Hassan and Dr. Lesley Wright. His research focuses on advanced gas turbine cooling technologies, including effusion and film cooling. His work combines experimental techniques such as pressure-sensitive paint along with numerical simulations using RANS and advanced CFD models.

Authors:

Omar Aly Texas A&M University
Ibrahim Galal Hassan Texas A&M University at Qatar
Lesley Wright Texas A&M University