Dispersed particles trajectory model , the interactions between the dispersed phase particles with the fluid , is often used to process the following ways : a fluid only consider the impact the relative dispersion of the particles , i.e., "one-way disaster bonding method ," which way flow field can be solved , and then solving the equations of motion of a solid particle , however, can only be used in this way for the dilute solid particle phase , otherwise will lead to large errors ; dispersed particles when the mass flow rate increases, would need to consider the interaction of the fluid phase and dispersed particles , namely, " Woe to close two-way approach " , which is a reflection of the increase of solid particle impact on fluid flow relative to the source term in the equation to get the flow field, but also on the flow field solid particle motion have an effect ; addition, if the nozzle is dense particles in the modeling phase ) , also taking into account the effect of a particle of a particle and a wall between the particles , known as " four-way disaster legal" , the method of construction mold and calculations are very complicated.