Recent advances in cavity-based scramjet engine- a brief review

At present, the critical issue related to design of scramjet engine is to achieve efficient mixing between the air and fuel. Among the several fuel injection strategies, cavity flame holder is identified as a well-organized method for supporting the ignition zone. In this review, some mixing enhancement approaches based on well-known cavity based injection scheme proposed in latest research works, are summarized in detailed. The influence of cavity on the performance of scramjet combustor is recapitulated from three aspects, namely variation of shape/geometry of cavity flame holder; location of fuel/air injection scheme; and recent progresses in dual/double cavity. This review reveals that the cavity rear wall-expansion is an innovative kind of cavity flame holder which has a great impact on the efficiency of scramjet combustor whereas the presence of micro air jets have improved the flame holding mechanism of scramjet engine. Additionally, the performance of scramjet is significantly improved by dual cavity indicating that the dual cavity flame holder would be a feasible preference for the future growth of scramjet engine.