Experimental investigation on combustion efficiency of a partially premixed kerosene-air rotating detonation combustor

It is believed that detonation waves travel a radially stratified mixture in a non-premixed rotating detonation combustor (RDC), which can result in non-ideal detonations. In order to further improve the combustion performance of RDCs, this paper presents a kerosene-air rotating detonation combustor with a partial premixing strategy, in which part of the fuel is injected into the air plenum to improve the mixing effect. A more convenient and accurate combustion efficiency evaluation method based on the mass flow function (MFF) and equivalent available pressure (EAP) is proposed to help to quantitatively study the combustion performance. A marked improvement in the combustion efficiency and operation range is obtained with increasing premixed equivalence ratio compared to a non-premixed strategy. The highest combustion efficiency for 0.3 premixed equivalence ratio can reach 98.06% in the experiments. The experimental results confirm that this partial mixing strategy can effectively prevent the flashback and improve combustion efficiency within a reasonable equivalence ratio. However, a total equivalence ratio and a premixed equivalence ratio that are too high will lead to a decrease in combustion efficiency and even failed detonation due to flashback events.