不同入口流量二沉池非牛顿液体/固体两相模拟

Numerical simulation of solid/non-Newtonian liquid two-phase flow in secondary sedimentation tanks with different inlet flow rates

采用数值模拟手段,在对模拟结果与现场测量结果验证的基础上,考虑二沉池混合液的流变性质、污泥回流比率等实际工况,以OpenFOAM开源流体力学代码为研究工具,针对不同入口流量下二沉池内固液两相动力学行为进行研究。结果表明:随着入口流量的增大,液相流速高值分布于入口区域并向污泥斗回流口区域波及,二沉池内液相流场结构由两层发展为三层;池内污泥浓度峰值不断提高,污泥层底部及污泥斗区域的污泥浓度高值区的面积不断扩大,出口及回流口污泥平均浓度增长幅度不断增大;二沉池上部的污泥沉降速度略微增大。

The OpenFOAM computational fluid dynamics package is employed to study the two-phase fluid behaviors in the tank.The package is validated through comparing numerical predicted velocity profile and sludge profile.Numerical tests of solid/liquid two-phase flows with different inlet flow rate and liquid recycling and rheological properties are performed.It is found that with increase of the inlet flow rate,the liquid velocity becomes relatively higher in the entrance area and expands to the reflux region of the sludge hopper.Liquid phase flow field develops from a two-layer structure to a three-layer structure.The peak concentration of sludge in the tank increases continuously,and the area with a high sludge concentration in the bottom of the sludge layer and the sludge hopper also expands.The average concentration of sludge at the outlet and reflux region of the sludge copper is also increases,and the sludge settling velocity in the upper part of the two sedimentation tanks increases slightly.