Numerical Simulation Of Pulse Detonation Engine Ddt

Pulse detonation engine (PDE) is a new concept of propulsive engine which uses intermittent detonation wave to generate thrust. It has potential advantage in thermodynamic efficiency,specific impulse,operation range,simplicity and variable thrust compared to propulsion systems currently in service. Efficient ignition is one of the key techniques. Since the energy required to initiate detonation directly is impractical. Low energy Source for detonation initiation to provide fast and reliable detonation has become the current focus.Most work around the world related to DDT is done in the way of experiment, In this paper,the DDT process have been studied using numerical simulations,mainly include following two aspects:Firstly,DDT is simulated under varying ignitor location(0.5 combustor diameter,1 combustor diameter,1.5 combustor diameter),ignition energy(ignition region diameter 5mm, 6mm,7mm). The numerical method is coupled-explicit solver. The chemical reaction for the stoichiometric hydrogen-air mixture is modeled by one-step Arrhenius kinetics. Results show that DDT distance is minimized with the ignitor located one combustor diameter from the head wall and it is helpful to reduce DDT distance,while using higher ignition energy.Secondly,DDT is simulated under varying obstacle spacing(0.5 combustor diameter, 1 combustor diameter, 1.5 combustor diameter), obstacle blockage ratio(blockage ratio 0.3,0.4,0.5). Results show that, obstacles create perturbations in the flowfiled of PDE; the periodic flow expansion and contraction is responsible for flame area enhancement;The interaction between shock and flame in the coner of obstacle accelerates the chemical heat release rate, and leads to the formation of hot spot. DDT distance is minimized when obstacle spacing is roughly equal to one combustor diameter, DDT distance decreased with increased blockage ratio.