Effects of thermal wall conditions on rotating detonation

- Boundary oblique detonation is induced by hot walls.
- Y-shaped rotating detonation is discovered.
- Transverse waves produce sub-peaks of pressure traces in the experiments.

Rotating detonation in an annulus full of stoichiometric hydrogen and air is numerically studied to figure out the effects of thermal wall conditions on detonation. A transient density-based solver with implicit formulation, a laminar finite-rate model with one step reaction, and a standard k-epsilon model are employed. It is found that after some time from ignition, boundary oblique detonation near the walls occurs and is included into the Y-shaped rotating detonation formed from the detonation front and transverse wave. The transverse wave is comprised of detonation attached to the rotating detonation front and shock. Boundary oblique detonation occurs with high wall temperature conditions, but it does not occur with adiabatic wall conditions. It is the rapid reaction caused by the high wall temperature that induces boundary oblique detonation. The length of boundary oblique detonation is increased with increasing wall temperature and time. The average velocity of rotating detonation for higher wall temperature is higher. Why continuous propagation of rotating detonation in engines without cooling is not broken by deflagration due to hot walls is explained. Numerical results show that transverse waves produce sub-peaks of pressure traces in the experiments.