Session: 12-01 LES applied to film cooling

Submission Number: 176585

LES-Based Analysis of Film Cooling in a High-Pressure Turbine Rotor Including Effects of Purge and Tip Flow 

Accurate modeling of coolant airflows, which form protective films over turbine blades, is essential for designing fuel-efficient and environmentally sustainable jet engines. Excessive coolant reduces thermal efficiency, while insufficient coolant leads to blade overheating and damage. Therefore, precise prediction of flowfield interactions with cooling air is critical for optimizing turbine performance. This study numerically investigates the cooling effectiveness of purge and film cooling flows within a high-pressure turbine (HPT) rotor using Large Eddy Simulation (LES) with NASA Glenn Research Center’s Glenn-HT solver. The simulation replicates the Penn-State University START rotating rig, representative of modern HPT rotor designs. A high-fidelity structured mesh comprising up to 800 million cells is employed to resolve high-Reynolds number flow (Re ≈ 350,000) and capture intricate secondary flow structures, including tip leakage and purge-induced vortices. Film cooling effectiveness computations are highly sensitive to boundary conditions at the cooling holes and to grid resolution. Even with well-resolved grids and plena included, strong mixing challenges traditional eddy viscosity models. To address this, a simplified configuration is simulated: a truncated row of shaped holes on the suction side near the leading edge and a row on the pressure side, both fed from internal plena while the purge slot and tip clearance are also modeled. Two LES cases are conducted—one with cooling and one baseline case without cooling under adiabatic wall conditions—to compute adiabatic wall temperatures and heat transfer coefficients. The latter is derived by imposing a constant wall temperature and evaluating the resulting heat flux. The simulations reveal detailed three-dimensional unsteady flow features, including coherent vortical structures and secondary flows originating from the purge cavity. Film cooling effectiveness and Nusselt number distributions are presented for both the blade surface and tip, highlighting regions of elevated heat transfer and complex thermal behavior. These findings underscore the importance of high-resolution LES and realistic boundary conditions in capturing the dynamics of purge and film cooling, offering valuable insights for improving turbine blade design and thermal management strategies.

Presenting Author: Ali Ameri Ohio State University

Presenting Author Biography: The presenting author is a CFD practitioner employed by the Ohio State University and has been collaborating with NASA since 1988. He is an ASME fellow.

Authors:

Ali Ameri Ohio State University
Kenji Miki NASA Glenn Research Center
Timothy Beach HX5, LLC
Douglas Thurman NASA Glenn Research Center
Philip Poinsatte NASA Glenn Research Center