  Numerical simulations were conducted to investigate the flow field
characteristics and performance of a carbon-hydrogen/oxygen-rich air rotating
detonation engine (RDE). Three distinct flow field structures were observed in
the gas-solid two-phase RDE. The results show that reducing the hydrogen
equivalence ratio and particle diameter both contribute to the transition from
gas-phase single-front detonation to gas-solid two-phase double-front
detonation and further to gas-solid two-phase single-front detonation. The
effects of solid fuel particle diameter and hydrogen equivalence ratio on the
flow field characteristics and performance are revealed. The results show that
reducing the particle diameter enhances the speed of the two-phase detonation
wave, improves the pressure gain in the combustion chamber, and increases the
specific impulse. Decreasing the hydrogen equivalence ratio reduces the
detonation wave speed, enhances the stability of the detonation flow field,
increases the pressure gain in the detonation wave and combustion chamber and
boosts thrust. Furthermore, the selection of operational conditions to ensure
stable operation and optimal performance of the RDE is discussed. In order to
take into account the requirements of stability, pressure gain performance and
propulsion performance, two-phase single-front detonation should be realized in
gas-solid two-phase RDE, and smaller hydrogen equivalent ratio and appropriate
particle diameter should be selected. According to the conclusion of this
study, the particle diameter should be 0.5-1 {\mu}m. Under such conditions, the
detonation flow field demonstrates good stability, allowing the RDE to achieve
higher pressure gain and specific impulse while maintaining stable operation.
