Numerical Simulation Of Flow Characteristics Of Non-newtonian Fluid In A Hydrocyclone

At present, the investigations for desander and desilter of mud solid control system mostly based on the experiments and numerical simulation for single-phase Newtonian fluids in hydrocyclones. But in real situations, muds represent on non-Newtonian rheology, so we must investigate it by using non-Newtonian fluids for the flow media, for obtaining more clear data of desander and desilter.First, the thesis did the numerical simulation research for water and power-law fluid in the 75mm hydrocyclone, used fluent6.2.16, the business software of Computational Fluid Dynamics(CFD), obtained the distributions of their velocity and pressure. The results showed that: average apparent viscosity of power-law fluid was bigger than dynamic viscosity of water; the tangential velocity was lower in outer vortex region, especially near the wall; and axial velocity was larger along the flow media changed from water to power-law fluid.Second, the thesis did the numerical simulation for different rheological parameters of power-law fluid: increased consistency index k led to increased average apparent viscosity, and then tangential velocity became lower in outer vortex region, but axial velocity and radial velocity changed inconspicuous. As power-law index n decreased, the shear shinning became stronger, the tangential velocity and radial velocity became higher in outer vortex region and axial velocity changed inconspicuous. On the whole, about the influences on flow field, pressure drops and separation efficiency were greater by the changes of n .Again, based on the results of flow field for water and power-law, the thesis calculated and analyzed path lines and separation efficiency of particles with different size in this two flow media, uesd dispersed phase models. Because of greater axial velocity of power-law fluid, particles with the same size had faster sedimentation rate and shorter settle time. Thereinto, particle with 15 ? m diameter didn't discharge from bottom outlet as shown below water field, but surrounded vortex finder to its bottom and overflowed from vortex finder. The separation efficiency and energy consumption of power-law fluid were lower than water, and separation size was bigger. Changes of consistency index k had small influence about separation efficiency, and decreased value of n resulted larger separation efficiency and energy consumption.At last, the thesis did the numerical simulation for different inlet velocity of two flow media, the results showed that: increased velocity led to larger separation efficiency and energy consumption, and energy consumption increased in water field, but separation efficiency didn't increase evidently.The results of numerical simulation of this article provided a theoretical basis on the research about flow field, separation performances and energy consumptions of desander and desilter.