Computationally Efficient Workflow for Conjugate Heat Transfer With LES for Gas Turbine Combustors

Abstract Typical Gas Turbine Combustor (GTC) and High-Pressure Turbine (HPT) stage generally employs 10,000 to 100,000 small passages of cooling holes. Such an arrangement protects the solid walls through impingement and effusion cooling. The former provides solid wall internal cooling, and the latter helps to reduce the metal temperature by developing a thin film around it. High-fidelity simulations are primarily utilized in the industry such that accurate prediction from numerical tools can aid advancement in the performance of such machines. In this paper, a numerical study using Ansys Fluent has been conducted with Large Eddy Simulation (LES), Conjugate Heat Transfer (CHT), and radiation to explore the relative benefits of implicit and explicit fluid-solid thermal coupling. The simulations of LES with CHT are performed for well-documented experiments of heated nozzle exhaust passing over a film-cooled plate [12]. The accuracy of the modeling approach is assessed by comparing CHT predictions of fluid velocity and solid-plate temperatures with experiments. Acceleration techniques for LES-CHT simulations are explored in this paper with an emphasis on thermal coupling, radiation, etc. The effects of mesh sensitivity and flow solution approach are presented in detail. LES-CHT results generally match the experiments at various blowing ratios both qualitatively and quantitatively. The comparisons in the paper allow the selection of best practices for CHT modeling in GTC. A generic combustor model with effusion cooling hole arrays is used in the paper to establish the workflow for modeling LES with CHT in the industrial-type combustor. Various acceleration techniques are utilized to show an overall improvement in solution performance with the same level of accuracy.