Session: 12-07 Optimization of Film Cooling Geometries

Paper Number: 79923

79923 - Large Eddy Simulation Based Optimization of a Fan-Shaped Cooling Hole Geometry to Enhance Cooling Performance 

In this study, a Large Eddy Simulation based approach is applied to optimize the shape of a fan-shaped hole in order to maximize the film cooling performance. A standard shaped cooling hole designated as the 7-7-7 [1] is selected for this purpose and the flow configurations close to those in real gas turbine conditions are used to model the numerical problem. Four of the most important geometrical parameters defining a cooling hole shape, namely the depth of the expanded section, the hole inclination angle and the forward and the lateral expansion angles are selected as the design variables to obtain the optimal hole shape. Forty design cases at start are selected via an Optimal Latin Hypercube Sampling method (OLHS) and further more are added in the initial database during the successive iteration steps of the optimization algorithm. The handling of these various design cases including the CAD creation of the geometries, computational domains, meshes and finally the numerical setup is handled by the LES based autonomous tool which has been previously validated [2]. Finally, the Bayesian based Efficient Global Optimization (EGO) [3] method along with the Expected Improvement (EI) as the acquisition function is used to maximize the surface averaged film cooling effectiveness as the objective function. After several database enrichment steps to reduce the overall modal error an optimal shape of the cooling hole with the highest cooling performance is obtained. Finer mesh settings are then used for some cases to recalibrate the model in the region of interest with improved LES prediction of the objective function. The optimal geometry thus obtained has a significantly higher cooling performance than the reference hole shape which is also confirmed via the study of the fluid flow distribution in both the cases. Overall, this study shows that, Large Eddy Simulations can be successfully coupled along with a EGO based optimization approach to obtain the optimal shaped cooling hole in a computer-aided optimization setting.

[1] Schroeder, R. P., & Thole, K. A. (2014, June). Adiabatic effectiveness measurements for a baseline shaped film cooling hole. In Turbo Expo: Power for Land, Sea, and Air (Vol. 45721, p. V05BT13A036). American Society of Mechanical Engineers.

[2] Agarwal, S., Gicquel, L., Duchaine, F., Odier, N., Dombard, J., Bonneau, D., & Slusarz, M. (2021, June). Autonomous Large Eddy Simulations Setup for Cooling Hole Shape Optimization. In Turbo Expo: Power for Land, Sea, and Air (Vol. 84973, p. V05AT12A010). American Society of Mechanical Engineers.

[3] Jones, D. R., Schonlau, M., & Welch, W. J. (1998). Efficient global optimization of expensive black-box functions. Journal of Global optimization, 13(4), 455-492.

Presenting Author: Shubham Agarwal CERFACS

Presenting Author Biography: Shubham AGARWAL is a PhD candidate in his final year at CERFACS working on film cooling from turbine blades. His major experiences are in the field of aero/fluid/thermal.

Authors:

Shubham Agarwal CERFACS
Laurent Gicquel CERFACS
Florent Duchaine CERFACS
Nicolas Odier CERFACS
Jérôme Dombard CERFACS
Damien Bonneau Safran Aircraft Engines
Michel Slusarz Safran Aircraft Engines