Computational Analysis of Rotating Detonation Engine Exhaust Interacting with a Turbine Vane

Rotating detonation engines (RDEs) are of interest because of the potential for high thermodynamic efficiency relative to a steady-flow Brayton cycle. In general, RDE combustion may appear as nearly steady flow to the turbomachinery since the detonation wave passing is so rapid. However, this has not been investigated in detail. For this study, Computational Fluid Dynamics (CFD) analyses using unsteady Reynolds Averaged Navier Stokes (RANS) were conducted on the effects of pulsed exhaust generated by a Rotating Detonation Engine (RDE) on a downstream turbine vane. A two-dimensional section of a public first stage turbine vane nominally designed for steady flow, was simulated with an incoming total pressure and temperature wave representative of the outflow of a rotating detonation engine combustor. The wave was modeled as an exponentially decaying pulse, with wave frequency, amplitude, and decay time constant varied to determine the impact on time average and unsteady behaviors in the vane passage. The results indicate that the instantaneous total pressure pulses of a detonation wave can propagate through the vane throat and influence the behavior of the trailing edge vortex shedding, which contributes to higher time-average total pressure loss. Furthermore, the vane surface pressure and convective heat transfer coefficient have much higher unsteadiness levels which could impact vane durability, and the turbine blade incidence angle can fluctuate significantly.