Abstract: The multiphase detonation model of plasma jet ignition is calculated by the two-dimensional viscous CE/SE method. The influence of viscosity on the detonation flow field under the condition of the plasma jet is analyzed through N-S equation and Euler equation. The influences of different ignition temperatures and time of the jet and initial droplet radius on the process of deflagration-to-detonation transition (DDT) are analyzed. The calculated results show that the viscosity has a very small effect on the propagation of detonation wave, while has some effects on the detonation parameters. DDT distance can be significantly shortened by improving the initial jet ignition temperature and time. When the plasma jet has fully ignites explosive mixture, a continual increase in jet time has little effect on the decrease in the distance of DDT. When the droplet radius is less than 50 μm，the peak pressure of detonation wave increases with the increase in droplet radius. When the droplet radius is more than 50 μm, the peak pressure of detonation wave decreases with the increase in droplet radius.

Key words: ordnance science and technology, pulse detonation engine, plasma jet, multiphase detonation, CE/SE method, deflagration to detonation transition