Investigation on mixing characteristics of rotating detonation combustor with convergent inlet

Mixing characteristics play an important role on the operational process of rotating detonation combustor (RDC). In this paper, a series of numerical calculations were conducted to analyze the influence of injection diameter, injection position, reactant mass flow rate, and equivalence ratio on mixing characteristics. Mixing performance parameters and total pressure loss in combustor dome and ignition zone were analyzed in detail. The findings indicated that all four injection conditions had significant influence on mixing characteristics, among which injection position was the most significant factor. When injection position was in convergent section, the mixing characteristics were better than those in ignition section. Reducing the fuel diameter gradually improved mixing characteristics, but also increased total pressure loss. The change of reactant mass flow rate had a minimal effect on mixing characteristics. As equivalence ratio decreased, mixing characteristics decreased and total pressure loss decreased. In addition, the comparative analysis also showed that penetration depth of hydrogen had an impact on flow field disturbance and distribution of return region, which led to the difference in mixing characteristics. When hydrogen was injected into the convergent structure section where air flow velocity did not reach sonic speed and was in acceleration phase, total pressure loss would be effectively reduced in combustor dome.