  The study presents a new type of detonation engine called the Ram-Rotor
Detonation Engine (RRDE), which overcomes some of the drawbacks of conventional
detonation engines such as pulsed detonation engines, oblique detonation
engines, and rotating detonation engines. The RRDE organizes the processes of
reactant compression, detonation combustion, and burned gas expansion in a
single rotor, allowing it to achieve an ideal detonation cycle under a wide
range of inlet Mach numbers, thus significantly improving the total pressure
gain of the propulsion system. The feasibility and performance of RRDE are
discussed through theoretical analysis and numerical simulations. The
theoretical analysis indicates that the performance of the RRDE is mainly
related to the inlet velocity, the rotor rim velocity and the equivalence ratio
of reactant. Increasing the inlet velocity leads to a decrease in the total
pressure gain of the RRDE. Once the inlet velocity exceeds the critical value,
the engine cannot achieve positive total pressure gain. Increasing the rim
velocity can improve the total pressure gain and the thermodynamic cycle
efficiency of RRDE. Increasing the equivalence ratio can also improve the
thermodynamic cycle efficiency and enhance the total pressure gain at lower
inlet velocities. While, at higher inlet velocities, increasing the equivalence
ratio may reduce the total pressure gain. Numerical simulations are also
performed to analyze the detailed flow field structure in RRDE and its
variations with the inlet parameters. The simulation results demonstrate that
the detonation wave can stably stand in the RRDE and can adapt to the change of
the inlet equivalence ratio within a certain range. This study provides
preliminary theoretical basis and design reference for the RRDE.
