Quantification of Heat Loads for Rotating Detonation Combustors with Gas Turbine Conditions

Rotating Detonation Combustors (RDC) offer a high-power density compared to other combustors. Although they must overcome many challenges to be integrated into a gas turbine (GT), it is certainly a promising solution for increasing cycle efficiency. Among the many challenges, cooling the RDC is one of the most predominant due to the high heat loads generated by the combustion process. Most of the available numerical and experimental data in the literature about RDC heat loads are obtained for laboratory conditions (i.e. at atmospheric pressure). However, to design a cooling system for an RDC that allows for its sustainable operation and aids its integration into GT engines, a quantification of the heat loads of an RDC operating at conditions representative of GT is necessary. The presence of a detonation wave/boundary layer interaction and a small annulus width leads to a high heat transfer when compared to a conventional GT combustor. This paper describes the numerical models and tools to estimate the heat flux and heat transfer coefficient of an RDC that would be relevant for setting cooling requirements in practical systems. The simulations are conducted using Ansys Fluent utilizing a single-step reaction mechanism. Since the flow in some parts of the RDC is supersonic, the compressible boundary relations are used to model the heat transfer. Integral boundary layer methods are employed to build a tool which uses 2D distributions of integral quantities to obtain the heat flux. A global heat transfer model is built using these simulations as a reference. The results have shown that the heat transfer in the RDC is enhanced by the presence of a blockage at the combustor outlet. The effects on the flow field are associated with an increase in chamber pressure and detonation strength, determining an increment of the heat transfer coefficient to the liner walls.