基于固液两相流模拟的选矿循环水深度澄清装置优化

Optimization of depth clarification device for beneficiation circulating water based on solid-liquid two-phase flow simulation

部分选矿循环水中含一定量的高分散性悬浮颗粒,仅依靠简单浓缩沉降难以澄清,无法达到回用要求.针对这一难题,提出了一种选矿循环水固体悬浮物澄清装置.为优化装置的结构参数与运行参数,建立了选矿循环水深度澄清装置的二维物理模型,基于计算流体力学(CFD)的方法,选用Mixture和RNG k-ε模型对装置主要的结构参数与运行参数展开了数值模拟研究.研究发现适当降低水力循环区喷嘴长度,增加喉管与喷嘴管径比、颗粒沉降区开口尺寸、装置直径等结构,能够降低颗粒沉降区平均湍动能,由于湍动能为单位质量流体由于紊流脉动所具有的动能,故降低了颗粒沉降区流场的紊流程度,增加了水流的稳定性,提高了装置对悬浮颗粒的去除效果;同时发现降低入口流速、增加悬浮颗粒粒径有助于提高悬浮物的去除率,当进水流速为0.1 m·s^(-1)、经过混凝的悬浮颗粒形成粒径大于100μm时,装置对选矿循环水中的悬浮颗粒去除效果显著.

Some beneficiation circulating water contains excess highly dispersed suspended particles,which are difficult to clarify only by simple concentration and sedimentation and cannot meet the requirements of reuse.To solve this problem,a clarification device was developed for removing the solid suspended matter from beneficiation circulating water,which consists of a hydraulic circulation area and a particle sedimentation area and integrating mixing,flocculation,and sedimentation.The flow field inside the gadget has a big influence on how well it works.The structural and operating parameters of the gadget were improved using the computational fluid dynamics approach to increase the device’s performance.A two-dimensional physical model of the deep clarification device for beneficiation circulating water was established.Numerical simulation research on its main structural parameters and operating parameters were conducted by using software Fluent and choosing the Mixture multiphase flow model and RNG k-εturbulence model.The effects of feed water nozzle length,throat to nozzle diameter ratio,sludge settling area opening size,and device diameter on the internal flow field were investigated.The average turbulent kinetic energy in the sludge settling zone can be reduced by reducing the length of the nozzle in the hydraulic circulation region,increasing the ratio of the throat to nozzle diameter and the opening size of the sludge settling area,and increasing the diameter of the device.Due to the fact that the turbulent kinetic energy is the kinetic energy of fluid produced by turbulent pulsation,the turbulent degree of the flow field in the sludge settling area is reduced,the effect of turbulent flow in the flow field on particle settling is weakened,and the removal effect of the device on suspended particles is improved.Simultaneously,it is found that at the same suspended solids concentration,reducing the inlet flow rate or increasing the suspended particle size helps to improve the removal rate of suspended solids.When the inlet flow rate is 0.1 m·s^(-1) and the coagulated suspended particles form particles with particle size more than 100μm,the removal effect of slime particles in beneficiation circulating water is remarkable.