Numerical investigation of flame propagation and performance of obstructed pulse detonation engine with variation of hydrogen and air

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Pulse detonation engine is a new technique of supersonic wave propagation and stands for high impulsive thrust. The objective of the present investigation is to analyze the detonation wave characteristic of a hydrogen–air mixture in the pulse detonation engine (PDE) having obstacles of blockage ratio 0.5. The three-dimensional reactive Navier–Stokes equations with realizable k − ɛ turbulence model are used to simulate the propagation of combustion flame. The reaction rate of excess hydrogen and excess air is modeled by reduced single-step chemical reaction model and simulated using ANSYS software FLUENT 14.0 code. The simulation results of the shock wave overpressure, deflagration-to-detonation transition run-up distance of different flames and flame velocities are reported at initial boundary condition of 0.1 MPa pressure and 293 K temperature. It has been observed that the obstacles create turbulence in the propagating flame and form strong Mach stems of high temperature, resulting in reduction in accelerated flame run-up length. However, the normalized detonation flame run-up distance increases as the mass of fuel increases in the mixture. Thus, the performance of PDE combustor was observed 4.46% at high overpressure generated by excess fuel (ϕ = 1.3).