Thickener Numerical Simulation With Computational Fluid Dynamics(CFD)

With the decreasing of freshwater resources and the increasingly strict requirements of ecological protection, the world pays high attention to the recycling of waste water and the disposal of solid waste.It is usually adopted that the technology of solid-liquid separation in the treatment of solid waste.Thickener as the important device for solid-liquid separation processhas been more and more widely used in various industrial areas. Therefore, the demand, that the water quality of overflow and solid concentration of the underflow in the thickener, has become increasingly high. In order to meet the increasing requirements, thickener must be designed scientifically to ensure process performance which closely depends to the treated materials. The key to improve the process performance of the thickener is to understand the characteristics of the handled materials, including solid particle size, solid density, solid flocculent property, and chemical properties of the solid surface, slurry viscosity, yield stress and other rheological parameters.Thus, it is very important to analyze the physical and chemical properties and the rheological characteristics of the solid materials. In this paper, XRD is used to analyze the phase of the samples. Particle size analysis was carried out using a laser particle size analyzer. On that basis, the flocculation settling experiment of the sample was carried out, and the rheological experiment and PIV experiment were also conducted. The optimal feed concentration was obtained. The custom model of the underflow solids concentration and the yield stress was formulated by using numerical fitting technique, and effective density of the flocculation was obtained by PIV technique, which provides reliable data for CFD simulation analysis.Based on above study, the model experiments of thickener and CFD simulation were setup. Mutual authentication has occurred between the experimental results and numerical simulation results, and we find that the numerical simulation results are reliable. Through the analysis of the results, the law of concentration distribution and velocity distribution were obtained.