With analysis on parallel plan for parallel turbine based combined cycle (TBCC) inlets

a method for classification and a type of parallel plan were proposed. Numerical simulations were conducted for four types of parallel plan inlet during the mode transition at Mach number of 25. Results showed that total mass flow rate kept nearly constant for pure internal parallel plan

contributing to stable thrust during mode transition; total mass flow rate decreased for other three plans. Pure externalparallel inlet with back door had the lowest mass flow rate of ramjet channel with a large change

other three plans had a small change. Total pressure recovery at turbine channel exit increased from a lower initial level during mode transition for pure internal plan; it decreased evidently from a high initial level for external parallel plan

but decreased within a narrow range for mixed internal plan.