This paper is devoted to the experimental and theoretical study of two-phase detonations where the fuel is in the form of a liquid spray and the oxidizer is air. Experimental investigations on two-phase pulse detonation engine(PDE) are conducted. The PDE model was operated over a repetition frequency range from lHz to 36Hz.The results of detonation velocity and over - pressure measurements are presented. The experiments show that the droplet sizes have profound effect on detonation velocity. The larger the droplet size or the smaller the evaporation rate, the higher the difference between two-phase and gaseous detonation velocities. The detonation velocity deficit for pulse two-phase detonation is less than single-phase one, due to secondary atomization by filling velocity and evaporation from heated wall. The velocity difference can be explained by considering heat transfer and shear losses to the tube wall within the reaction length, which is reasoned to be controlled by the breakup time of the fuel drop One-dimensional approximation for the propagation of two-phase detonation, which takes mass, momentum heat transfer from the reaction zone into account, is presented. A simplified formula for two-phase detonation velocity is established which considers, effects of drag , heat losses, fuel and oxidizer ratio, droplet diameter, fuel evaporation and detonation tube sizes The predicted two-phase detonation velocities are in reasonable agreement with the experimental results. The physical model for two-phase detonation waves is developed which can explain the mechanism of two-phase detonation wave propagation.
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