废水深度处理反应器流体数值模拟与优化

Flow Numerical Simulation and Optimization for Wastewater Advanced Treatment Reactor

利用Fluent软件对废水深度处理反应器的流体进行三维数值模拟比较,结果表明:旋流式布水器可在反应器内形成类似于桨式搅拌器的流态形式,搅拌效果好。示踪剂模拟显示,相对于消能引流布水器,旋流式布水器粒子滞留时间更接近理论停留时间,返混更小,可作为深度处理反应器的布水器。对深度处理反应器进行数值模拟,结果显示流体经过催化剂层后只存在上向层流,无搅拌混合作用,影响药液混合反应效果,采用螺旋折流板对反应器进行优化,优化后的流速矢量发散并有旋流涡流,流体搅拌更充分,优化后速度接近原来的4倍。优化后的深度处理反应器压力降主要位于进口处,其次位于催化剂层,螺旋折流板对压力的损失可以忽略。

Simulated with Fluent, swirling water distributor could make a fine mixing effect as similar with the flow pattern of paddle agitator. Discrete Phase Model showed the residence time of particle in swirling water distributor is closer to theoretical value, and back flow was less than in cone water distributor. Swirling water distributor could be used as wastewater advanced reatment l：eactor. Numerical simulation showed that the laminar flow without mixing effect is occured after throughing catalysts layer. The advance treatment reactor was optimized with helical baffle installed up the catalysts, then the velocity vector was divergent and fluid was mixed efficient, the velocity was nearly four times than that before. The pressure drop of optimized reactor was mainly located at the inlet, then at the catalysts, the pressure loss of helical baffle could be ignored.