•The rotating detonation waves fueled by kerosene/air mixture are simulated.•Quasi-2D simulations of rotating detonation engine (RDE) with discrete injection model are performed.•Detonation cellular structure of rotating detonation waves is discussed.•The influence of discrete reactants on rotating detonation cellular structure is studied.•The deflagration zone in triangle gas layers is studied and compared with experimental result. The propagation of multiple detonation waves in the two-dimensional modeled rotating detonation combustor fueled by premixed kerosene/air mixtures is numerically investigated with a reduced two-step global chemical mechanism. Discrete fuel injection model is adopted to simulate the discontinuous distribution of reactants in Rotating Detonation Engine (RDE) experiments. A parameter inlet-area ratio (ψ) is proposed to obtain the reactants with different dispersion degree. This work focuses on the effect of discontinuous reactants on detonation cells and overall flow-field structure of rotating detonation waves. The results show that with full-area injection model (ψ=1.0), the reactants distribute continuously in triangular gas layers. Rotating detonation waves propagate stably with regular detonation cellular structure. When ψ is less than 1.0, the injection reactants are distributed in strips. At the position far away from the head-end wall of combustor, the fresh reactants and combustion products are mixing with each other which causes the deflagration zones in triangle gas layers. The reactants remaining after deflagration process in deflagration zones cannot support the propagation of detonation leading to the partially decouple of detonation front. The large area of deflagration zones distorts the flow-field structure and reduces the propulsion performance of combustor.