Deflagration-to-detonation transitions (DDTs) in nitromethane mist/air mixture clouds, flaked aluminum dust/air mixture clouds, and nitromethane mist/flaked aluminum dust/air mixture clouds have been studied in an experimental tube of inner diameter 199 mm and length 29.6 m. The mist/dust/air multiphase mixtures were generated by injecting liquid/dust samples into the experimental tube. The droplet dimensions of the nitromethane mist cloud were analyzed, calculated, and measured. The multiphase fuel/air mixture clouds were ignited by means of an electric spark. The characteristics of different stages during the DDT process in the clouds of the various mixtures in the experimental tube have been studied and analyzed. A self-sustained quasi-detonation wave formed in the nitromethane mist/air mixture clouds, while a self-sustained detonation wave formed in the flaked aluminum dust/air mixture clouds and in the nitromethane mist/flaked aluminum dust/air mixture clouds. The detonation parameters of the clouds of the different mixtures have been studied and compared.