For describing the cluster phenomenon and its effect on drag force in gas-solid two-phase flow,the paper analyzed theoretically develped a model of gas-solid drag force in Eulerian frame under consideration of cluster effects by using the energy minimization concept.

To describe the cluster phenomena and their effects on drag force, a new model of gas\|solid drag force is developed under the consideration of cluster effects using the energy minimization concept.

In order to get a simple and low-cost method to reflect the nanoparticles aggregation quantitatively,the relationship between nanoparticles aggregation and nanofluids transmittance was analyzed and the mean particles number of nanoclusters was proposed as a parameter to reflect the nanoparticles aggregation quantitatively.

Using a new algorithm based on particles aggregation theory to calculate the thermal conductivity of nanorefrigerant,the thermal conductivities of two kinds of copper-water nanofluids were calculated and contrasted with experimental data.

In order to study agglomeration and fragmentation phenomena in dense gas-solid flows, a new method, in which Particle Tracking Velocimeter(PTV)-a visualizable technique has been developed, is proposed on the basis of the correlation between kinematic information such as velocity and dynamic parameters of moving particles.

The hydrodynamics of particle agglomeration flow was numerically simulated at the different inlet gas velocity, initial particle size distribution and type of agglomeration mechanisms in the absorber.