CFD simulations of two-phase flow

When doing computational fluid dynamics (CFD), there are two methods generally used to describe two-phase flow, which are Euler-Euler (E-E) model and Euler-Lagrange (E-L) model. In E-E model, particles are treated as a fluid, and also have stress, pressure and other characters that possessed by a continuous phase. On the contrary, E-L model treats particles as a discrete phase, and tracks movement of individual particles. In this chapter, both E-E and E-L methods are used and compared in the simulations of coal combustion, pneumatic conveying and aeolian sand movement. E-L model is a very time-consuming method, but it avoids extra models for particle phase. E-E model directly gives the statistical regularity of particle performances, but unreasonable sub-models may result in unreasonable predictions. This chapter analyzes advantages and disadvantages of both E-E and E-L models and proposes a new methodology that combines two methods to make reasonable predictions while spending comparative less computational time