Effect of equivalence ratio on rotating detonation combustion with n-heptane sprays

Abstract

Three-dimensional simulations are conducted for rotating detonative combustion fueled by n-heptane sprays without any fuel pre-vaporization. Parametric studies are performed to study the influences of equivalence ratio on the rotating detonation wave. The decoupled process of the detonation wave with lean equivalence ratio is also been analyzed. It is found that when the global equivalence ratio is lower than 0.6, a stable propagating detonation wave cannot be observed in the combustion chamber. With the gradual increase of the global equivalence ratio, the detonation wave can stably propagate in the combustion chamber after ignition. When the global equivalence ratio is 0.8–1.5, the propagation mode of the detonation wave in the combustion chamber is one-way propagation mode. When the global equivalence ratio gradually increase from 0.8 to 1.5, the formation time of the detonation wave first decreases and then increases with the increase of the equivalence ratio. Besides, the stability of the detonation wave first increases and then decreases with the increase of the equivalence ratio. Moreover, the thrust of the rotating detonation chamber fueled by n-heptane increases gradually with the increase of the equivalence ratio. The specific impulse of the combustion chamber first increases and then decreases with the increase of the equivalence ratio.