Numerical investigation on multi-cycle operation of pulse detonation rocket engine

In order to investigate the multi-cycle operation process of pulse detonation rocket engine (PDRE), estimate the propulsion performance and obtain the regulation of the control parameters for performance optimization, a one-dimensional unsteady performance analysis model of PDRE is established and a CFD code is developed. The AUSM scheme and the third-order TVD Runge-Kutta method are used for spatial and temporal discretization, respectively. Chemical kinetics is modelled by a one-progress-variable scheme. The stiffness is dealt with by using the Strang-splitting method and fully implicit method. Through the simulation of the PDRE utilizing stoichiometric hydrogen/oxygen as the detonative mixture and nitrogen as purge gas, it can be found that the flow field in the detonation tube is much more complicated in multi-cycle operation due to the coupling of each cycle, compared with in single-cycle operation. The effects of the duty cycle of the filling period on now characteristics and propulsion performance are also investigated here. As the duty cycle of the filling period decreases, the average thrust reduces too, but all filled mixture based specific impulse and detonative mixture based specific impulse increase. However, if the duty cycle of filling is too small, the gas temperature at the exit of PDRE will significantly increase. The results suggest that appropriately reducing the valve duty cycle of filling to decrease detonative mixture filling length can improve the propulsion performance and make PDRE run in an economical way.