Abstract: Aiming at the problem that the relationship between material properties and mixing performance was difficult to determine in the use of planetary centrifugal mixer(PCM), the effects of fluid viscosity and density on the mixing performance of PCM were studied by computational fluid dynamics(CFD) simulation. Firstly, the computational domain was modeled and meshed by ICEM CFD, and the independence of the grid was analyzed. Then, the second order finite volume method and discrete phase model were used to solve the particle trajectories, low velocity regions and discrete particle distribution of PCM mixing fluids with different viscosity and density, and the mixing effect was quantitatively characterized by the mixing index defined. Finally, the influence mechanism of fluid viscosity and density on the mixing performance of PCM was analyzed. The results show that fluid viscosity and density change the mixing effect of PCM mainly by affecting the flow field structure. The growth of fluid viscosity contributes the increase of optical speed ratio and the smaller value of mixing index that can be achieved; the growth of fluid density contributes the decrease of optical speed ratio and the greater values of mixing index that can be achieved. The research provides references for the use and optimization of PCM.

Key words: planetary centrifugal mixer(PCM);mixing performance;material characteristics;numerical simulation; computational fluid dynamics(CFD);fluid viscosity