Abstract: The dynamics of nanoparticle-laden multiphase flow is a newand important research field. To understand the basic interactionbetween phases and their physical nature, some problems are studied,including the closure for particlegeneral dynamic equations; the construction of the coagulation kernel; thefundamental interaction between particle dynamics and flow coherentstructures; the theoretical analysis on collision rate and some engineeringapplications. A new general mathematical method for solving thegeneral dynamic equation is proposed, and applied in someengineering problems.