膜蒸馏组件结构优化计算流体力学模拟及实验研究

Computational Fluid Dynamics Simulation and Experimental Study on Membrane Distillation Module Structure Optimization

为提高膜蒸馏过程中的渗透通量,对膜组件料液侧流道进行优化,利用计算流体力学(CFD)软件,对3种膜组件(模型A、模型B、模型C)进行三维模拟计算,对比分析各膜组件的内部流动状态、温度极化系数(TPC)、浓度极化系数(CPC);同时,考察流道优化后膜通量和热效率的变化情况。模拟结果表明:模型A内存在主流区和回流区,模型B内分区现象消失,模型C内流动最为复杂;模型A温度极化最严重,模型B浓度极化最严重,模型C各极化现象最弱;此外,模型C在膜通量方面比模型A提升至少90%,对于热效率,模型C最高,模型A与模型B在不同工况下存在差异。最后,选取模型C进行实验,发现实验值与模拟值吻合良好,验证模型的准确性。结果表明:流道优化能极大改善膜蒸馏的通量问题,研究结果为进一步优化内部结构提供了科学依据。

To improve the permeation flux of membrane distillation process,the feed liquid side channel of membrane module was optimized using a computational fluid dynamics(CFD)tool.Three types of membrane models(A,B,C)were designed,calculated in 3-dimension,and compared in terms of internal flow structure,temperature polarization coefficient(TPC),and concentration polarization coefficient(CPC).In addition,variations in membrane flux and heat efficiency were investigated in the optimized channel.Results show that first,there were a main flow and recirculation flow region in model A,the flow separation disappeared in model B,and the flow structure was most complicated in model C.Secondly,model A had the strongest TPC,model B produced the worst CPC,and model C had the weakest TPC and CPC.Thirdly,the membrane in model C was increased by 90%and model C had the best heat efficiency.Fourthly,heat performance between models A and B was quite different.Finally,model C was chosen for the experiment.The experiment and simulation agreed in general,which confirmed the validity of the simulation model.Therefore,the channel optimization could enhance the flux of membrane distillation,being good for further optimization of internal structure.