Numerical research on flow and performance of adaptive throat combustor for wide-range scramjet

This paper presents a special design concept for a fixed-geometry combustor, which is adaptable to a wide range of requirements for future scramjets. The design is based on the principles of staged combustion and the integration of a geometric throat. In low-speed inflow conditions, the combustor optimizes subsonic combustion performance through the choking effect created by the geometric throat. In contrast, under high-speed inflow conditions, the aerodynamic properties of the open cavity establish a boundary downstream of the combustor. This design mitigates the negative impacts of the geometric throat in supersonic flow, resulting in improved combustion performance under high-speed inflow conditions. This paper examines how the combustor flow channel expansion ratio affects the combustion flow field and performance parameters at flight Mach numbers from 3.0 to 7.0, with a kerosene equivalence ratio of 1.0. This paper verifies the feasibility of the new design concept with a specific adaptive throat combustor. To illustrate the advantages of this combustor, a traditional thermal throat combustor is present for comparative analysis of combustion performance and internal flow field parameters at typical flight Mach numbers. The results show that under inflow conditions corresponding to Mach numbers 3 to 5, the combustion performance of the adaptive throat combustor significantly exceeded that of the thermal throat combustor. Under inflow conditions corresponding to Mach numbers 6 to 7, the adaptive throat combustor’s performance was slightly lower than that of the thermal throat combustor. Therefore, this design concept holds considerable promise for practical engineering applications.