Film-Cooling Evaluation in a Microrotating Detonation Combustor Using Infrared Thermography

Integrating rotating detonation combustors into practical gas turbine systems remains challenging, with thermal management emerging as a critical issue due to the extreme heat flux generated during detonation. These high thermal loads generated during operation present significant challenges for practical implementation, making the development of effective cooling strategies essential to ensure structural integrity and sustained performance. Small-scale rotating detonation combustors provide an effective platform for investigating detonation dynamics, offering reduced manufacturing costs and standardized geometries that enable systematic exploration of fundamental combustion processes. This study presents the design and development of a dedicated experimental facility to investigate the application of film cooling in an oxygen–ethylene-fueled small-scale rotating detonation combustor. The objective is to evaluate the effectiveness of film cooling in reducing thermal loads on the combustor walls while assessing its influence on detonation wave behavior, including stability, propagation characteristics, and overall combustion performance. Experimental results demonstrate stable detonation over a wide range of film-cooling injection flow rates with only a minimal effect on detonation wave speed despite the associated increase in system backpressure. Furthermore, the results demonstrate that cooling effectiveness increases in a predictable manner with the coolant mass fraction and with downstream development of the film, as well as that the choice of coolant species becomes increasingly important as the equivalence ratio increases.