Combustion characteristics of hydrogen-air mixture in pulse detonation engines

The literature review reveals that the supersonic combustion wave remains a helpful method for improving the efficiency of pulse detonation engines (PDEs). A number of experimental studies have been conducted on detonation waves, which are formed by deflagration-to-detonation (DDT) transition waves. In this work, a straight PDE tube with a length of 1200 mm and a circular cross section measuring 60 mm in diameter is considered for combustion analysis. The combustion mechanism of stoichiometric hydrogen-air mixture is modeled by a three-dimensional Navier-Stokes turbulence model with a one-step reduced chemical kinetic reaction model using ANSYS Fluent software. The detonation tube contains obstacles with various blockage ratios of 0.5, 0.6 and 0.7 with 60 mm spacing (S) between them. Initial boundary conditions of 0.1 MPa pressure and 293 K temperature are applied to the hydrogen-air mixture to initiate combustion. The objective of the present work is to analyze the combustion flame generation and development of a stable detonation wave in the PDE tube. The flame rapidly develops and accelerates due to the burning of unburnt fuel particles in the leading zone and reduces the DDT run-up length.