Numerical Simulation Of Pulp Flowage In Bio-oxidation Pretreatment Based On CFD

The concentration of pulp in the reaction tank after biological oxidation pretreatment is an important factor affecting the survival and oxidation efficiency of bacteria.However,the reaction tank is a multiphase complex turbulent flow.The distribution of mineral powder particles is difficult to determine,and the parameter measurement is difficult and inaccurate.In order to solve the above problems,in order to obtain the distribution of the flow field in the tank of biological oxidation pretreatment,the CFD software is used to simulate the solid-liquid two phase flow field in the reaction tank,and the distribution of the volume fraction of the pulp at different rotational speeds is studied.First,the advantages and disadvantages of parameters measurement and parameter calculation in biological oxidation pretreatment are introduced.The theory of solid-liquid two-phase flow and its related equations are introduced.Then the three-dimensional solid model of the biological oxidation pretreatment tank is established and the boundary conditions are set up and the boundary conditions are set.Finally,it is carried out.In numerical simulation,using the standard k-e model and multiple reference system,the two order upwind difference scheme based on the two Euler equation is used to simulate the flow field in the reaction slot in the ANSYSA17.2 software,and the volume fraction distribution of the mineral particles at five different speeds is obtained.When analyzed the simulation data,dealt with the related data and observed the cloud and trend diagram in the simulation results,I analyzed the distribution of the mineral powder volume fraction at different concentrations and different rotational speeds:(1)There are vertical circulation and circumferential circulation in the reaction tank.The vertical circulation plays a major role in the distribution,and there are small circulation zones and dead zones near the bottom of the tank;(2)The volume fraction of mineral powder decreases with the increase of vertical height,and its value reaches the maximum value at the bottom of the trough,and gradually increases from the center to the wall of the tank;(3)Different agitation speed affects the distribution of mineral powder.The increase of concentration is the corresponding increase of stirring speed,and the relationship between the two is nonlinear;(4)When setting different speeds at different concentrations to simulate and get the optimal speed under this concentration.