  In a real propulsion system, shock-droplet interaction is often accompanied
by phase change, which has a significant effect on the deformation and
fragmentation of the droplet. In this paper, we study the effect of phase
change on the n-dodecane droplet propulsion, deformation and fragmentation
impacted by shock waves with high-resolution numerical simulations. First, we
conduct a comparative study on shock waves and n-dodecane droplets interaction
with and without phase change model. The impact of the shock wave changes the
pressure and temperature distribution around the droplet, causing the droplet
liquefaction on the windward side. With the influence of phase change, the
Kelvin-Helmholtz instability (KHI) waves on the windward surface are enhanced,
the development of KHI waves on the leeward surface of droplet is inhibited by
vaporization. Furthermore, it is found that phase change suppresses both the
flattening of the cylinder and shearing of the sheet at droplet equator. Next,
we investigate the effect of Mach number on shock-droplet interaction with
consideration of phase change. As the shock Mach number increases, the
flattening and vaporization of droplets are suppressed, the KHI waves on the
windward surface and the shear stripping of the sheet at the droplet equator
are enhanced. The shear stripping of the liquid sheet plays a more dominant
role in the deformation and breakup process than the flattening of the droplet
under the SIE breakup mechanism in a higher Mach number.
