Research On The Flow Characteristic Of Non-newtonian Fluidized Bed

Fluidized bed is the most important equipment for particle fluidization, the liquidsolid fluidized bed is an important branch of fluidized bed technology. In liquid-solid fluidized bed, fluidization of solid particles is particulate fluidization, so that two phases can be fully contacted and the heat transfer and mass transfer between two phases can be greatly promoted. Due to these advantages of liquid-solid fluidized bed, it has been used in mineral selection, chemical synthesis, wastewater treatment and some other fields.Different from Newtonian fluid, the rheological properties of non-newtonian fluid has its special point, namely the relationship between shear stress and shear rate is not the linear relationship. According to the presence of yield limit, non-newtonian fluid can be divided into power-law fluid and bingham fluid. Researchers put forward many equations to describe the constitutive relation of non-newtonian fluid. In numerical calculation, the rheological properties of non-newtonian fluid can be reflected by the constitutive equation.First, This paper introduces the research situation of the liquid-solid two-phase flow and the two-phase flow of non-newtonian fluid. Also, main methods of numerical calculation of liquid-solid two-phase flow are introduced. Finally, the two-fluid model is determined to be used as the mathematical model of this paper. The geometric models are selected from the reference literatures. So a bubbling bed model is selected for powerlaw fluid and a riser model is selected for bingham fluid.By the constitutive equation of power-law fluid, the decision of two main parameters of power law fluid is its flow index and consistency coefficient. In order to get the relationship between the two-phase fluidization character of the bubbling bed and the two factors, in this paper, I make all the factors keep the same except convection index and consistency coefficient in the numerical calculation. The characters are studied through the analysis of fluid velocity, particle velocity, bed expansion height, bed particle concentration, fluid turbulent kinetic energy, fluid turbulent dissipation rate and particle temperature.Through the constitutive equations of bingham fluid, the decision of two main parameters of power law fluid is its yield limit and consistency coefficient. In order to get the relationship between the two-phase fluidization character of the riser and the two factors, in this paper, I make all the factors keep the same except convection index and consistency coefficient in the numerical calculation. The characters are studied through the analysis of fluid velocity, particle velocity, bed expansion height, bed particle concentration, fluid turbulent kinetic energy, fluid turbulent dissipation rate and particle temperature.