Effect of Film Cooling Hole Location on Flow Dynamics in a Rotating Detonation Combustor

Detonative combustion can be employed to develop high-power-density combustors, such as the rotating detonation combustor (RDC). The high combustor mass flow, combined with the significant heat release from detonation waves occurring near the walls of the narrow annulus, results in immense thermal loads on the walls. Managing these thermal loads is crucial for the successful application of RDCs in gas turbines. Previous studies have suggested that film cooling may offer a viable solution for mitigating the intense thermal loads. However, the impact of the coolant mass addition location on RDC performance remains unclear. Four film-cooled RDC architectures are investigated, where the holes covered different portions of the outer wall from near the reactant injection location to downstream in the oblique shock region. The high circumferential and axial pressure variations resulted in differing coolant flows, while the added coolant mass increased the chamber pressure. The increased chamber pressure significantly altered the fresh gas refill structure and the detonation height. Regarding cooling performance, the various cooling schemes had different impacts on how much the wall temperatures were reduced. Ultimately, having cooling further downstream was most effective at overall cooling of the outer wall. However, placing coolant jets in the detonation region modifies the initial mixture characteristics, affecting the detonation combustion. In each cooling scheme, the injected coolant reacted with the unburnt fuel, leading to additional secondary deflagration heat release, which reduced the amount of unburned hydrogen at the exit.