Experimental study on a premixed rotating detonation combustor using Tesla inlet configuration fueled by kerosene

Abstract

The working performance of a rotating detonation combustor (RDC) can be enhanced by improving the mixing effect. Presently, most non-premixed injection schemes are adopted for safety purposes. However, the propellant in the premixed injection is completely mixed and thus can improve the working performance of RDC. In this study, kerosene and 28.5% oxygen-enriched air (at room temperature) were taken as the propellant, and the Tesla valve inlet structure was installed upstream of the combustion chamber to successfully realize a stable and self-sustaining propagation of the rotating detonation wave (RDW) under a premixed injection scheme. The propagation characteristics of the RDW and the performance of RDC under premixed and non-premixed injection conditions were then compared. The lean flammability boundary of RDC was effectively widened, and the intensity of the RDW was improved under premixed injection due to the better mixing effect of propellant and higher activity of combustible mixture. However, the high propellant activity led to premature combustion of the fuel, thus reducing the equivalence ratio boundary of RDC by about 50%.The RDW intensity was significantly higher under premixed injection than under non-premixed injection when the airflow rate was increased. The pressure feedback was quantitatively analyzed using the percentage of the pressure fluctuating amplitude in the air plenum to the pressure amplitude of the detonation wave (PFdw). The feedback intensity was closely associated with the intensity of the RDW (minimum PFdw; about 22%). The specific thrust was increased by about 48.3% (maximum specific thrust; about 743 N·s·kg−1), and the specific fuel consumption was reduced by 36.8%(minimum specific fuel consumption; about 0.24 kg·(N·h)-1) under the premixed condition. Meanwhile, the flow field of the inlet throat of RDC under premixed injection was subsonic, which greatly reduced the inlet pressure loss and further improved RDC performance.