基于CFD的渗滤液输运管道结垢特性的数值模拟

为缓解垃圾渗滤液输运对管道的结垢影响，设计了渗滤液浸置管材的结垢实验，以实验数据驱动计算流体动力学建模，模拟了渗滤液在直管和90°弯管中的结垢变化趋势，探究了不同管型中垢物的沉积变化特征，分析了温度、流速、管壁粗糙度、垢物粒径等因素对垢物沉积的影响。结果表明：渗滤液输运管道垢物中无机垢和有机垢的占比分别为75.6%和24.4%,垢物晶体成分主要是CaCO₃,伴有少量NaCl;垢物沉积量与温度呈正相关，与流速、污垢粒径呈负相关，壁面粗糙度对沉积量影响相对较小；直管和90°弯管2种管型内垢物在多个影响因素作用下的平均沉积率分别为1.26%和7.45%,90°弯管内垢物沉积量显著大于直管。该研究结果可为渗滤液输运管路系统设计与优化提供科学依据。

NUMERICAL SIMULATION ON SCALING BY LEACHATE PIPE TRANSPORT BASED ON CFD

To mitigate the scaling by landfill leachate pipe transport, this study designed a fouling experiment by placing the pipe materials into the leachate. The computational fluid dynamics modelling was driven by the experimental data, to simulate the scaling process when the leachate flowing a straight pipe and 90° elbow-shaped pipe, respectively. The characteristics of scale deposition regard to the two pipe shapes were discriminated, and the impacts of different factors, including temperature, flow velocity, pipe wall roughness, scale particle size etc., were investigated. The results showed that the proportions of inorganic scale and organic scale in the scales by leachate pipe transport were 75.6% and 24.4%, respectively. The crystal composition of the scales was mainly CaCO₃, accompanied by a small amount of NaCl. The scale deposition was positively correlated with temperature, negatively correlated with velocity and scale particle size, while pipe roughness had little effect on the deposition. The scale deposition in the 90° elbow-shaped pipe was larger than that in the straight pipe, and the average deposition rate regarding the straight pipe and 90° elbow pipe was 1.26% and 7.45% by the simulation. The research results can provide insight into the optimal design for the leachate pipe transport system.