Session: 12-01 LES applied to film cooling

Submission Number: 175501

Large Eddy Simulation of Compound Angle Effects of Trenched Shaped Holes on Cooling Effectiveness 

Gas turbines play a critical role in both power generation and aero-propulsion applications due to their high thermal efficiency. To further enhance their performance, modern turbines are designed to operate at increasingly higher turbine inlet temperatures, often approaching 2000K. Such extreme conditions, however, exceed the melting point of conventional blade materials, making effective cooling strategies indispensable. Film cooling approach is a key technique, in which coolant is injected through discrete holes to form a protective air layer over the blade surface, shielding it from the hot mainstream gas flow and thereby improving turbine durability and performance. Fan-shaped cooling holes have been recently applied in advanced gas turbines because of their reduced jet momentum and improved lateral spreading of the coolant. Among various enhancement strategies, passive approaches such as thermal barrier coating (TBCs) and trenched-slot configurations have shown strong potential by improving coolant distribution across blade surfaces. In this study, high-fidelity numerical simulations are performed to investigate the influence of compound angle (CA) on flow structures and film-cooling effectiveness for a fan-shaped cooling hole embedded in a two-dimensional trench on a flat plate. The trench configuration was selected based on an optimization study conducted previously by the authors. Four different cooling hole orientations (CA15, CA30, CA45, and CA60) are investigated using a 3D compressible large eddy simulation (LES) approach in Simcenter STAR-CCM+ V23.02. The film-cooling effectiveness calculated by the LES approach is validated against pressure-sensitive paint (PSP) measurements from the University of Bergamo for the reference case. Computational results demonstrate that cooling performance and turbulent flow characteristics are strongly dependent on the cooling hole orientation within the trench cavity.

Presenting Author: Ali Zamiri Bristol University

Presenting Author Biography: Ali Zamiri is a Lecturer in Propulsion and Aerodynamics at the University of Bristol, UK. He received his Ph.D. in Mechanical Engineering from Korea University in 2018, with research focused on turbomachinery aerodynamics and diffuser vane optimization. His expertise spans computational fluid dynamics (CFD), heat transfer, and the application of advanced optimization and machine learning methods to improve the aerodynamic and thermal performance of compressors, turbines, and film-cooling systems.

Authors:

Ali Zamiri Bristol University
Giovanna Barigozzi University of Bergamo