This book deals with the computational modeling aspects of chemical explosions and their interaction with reactive metal particle clouds, and is intended to assist researchers in the field. It is the outcome of the doctoral dissertation research work of the author at the Georgia Institute of Technology. The primary focus of the book is on the simulation of three-dimensional explosions from homogeneous and heterogeneous, two-phase explosive charges. The computational modeling issues are elaborately discussed in this book, and the physics of explosions are elucidated. The growth of Rayleigh-Taylor and Richtmyer-Meshkov instabilities in explosions are characterized, including their interaction with reactive metal particles. Furthermore, the physics of clustering of metal particles in their explosive dispersal is elaborated. Overall, this book summarizes the physics of multiphase explosions and provides useful insights to better understand this challenging fluid mechanic problem.