Maximum thrust for the rocket-ejector mode of the hydrogen fueled rocket-based combined cycle engine

•A thermodynamic cycle analysis model is developed to evaluate the thrust of RBCC.•The thrust of the ejector mode depends on the inducted air and thermal efficiency.•The optimum ejecting ratio at which the thrust attains a maximum is presented.

Rocket-based combined cycle (RBCC) Engine can significantly reduce the amount of onboard oxidizer required. This will decrease the weight of the vehicle and improve the performance of the RBCC engine. In this short communication, an idealized thermodynamic cycle analysis is carried out to evaluate the thrust performance of RBCC engine for the saturated supersonic regime. The thrust for the rocket-ejector mode not only depends on the inducted air flow rate, but also depends on the thermal efficiency. Initially, the results show that the engine thrust grows asymptotically with ejecting ratio, then reaches a maximum, and finally reduces rapidly for a given primary stream conditions. The optimum ejecting ratio at which the value of the thrust attains a maximum is also presented.