基于滑移网格的反应釜内部流体动力学特性研究

摘要

基于滑移网格理论，采用 VOF 模型，应用计算流体动力学法（CFD）对现实生产中尿素水解搅拌反应釜的内部流场进行数值模拟，分析不同时刻的反应釜内部流场、流速与湍动能分布等的变化特性，以及不同时刻该反应釜内部气液两相的分布状态和流动规律，并得出结论：液体流速较大的区域出现在3个桨叶区，碰撞釜体后形成轴向流和大小不同的涡流，并产生液体流动死区；最大压力出现在釜顶和釜底，而压差最大的区域则是搅拌叶附近；流场的湍动能自下而上逐渐增大。%Numerical simulation on internal flow field of stirred tank reactor for urea hydrolysis in practical production is done in this study ,which adopts both the VOF model and the software FLUENT ,based on sliding mesh method.The characteristics of distribution changes of internal flow field ,flow velocity and turbulent kinetic energy of reaction kettle on different times at the beginning of reaction ,as well as the law of distribution and flow condition of gas -liquid phases in the reaction kettle,are obtained.Consequently, the following conclusions can be obtained :the liquid in the three blade areas has larger flow velocity ,and the axial flow,the eddy current of different sizes ,and additionally the dead zones of liquid flow ,appear af-ter the liquid crashing into the kettle body ;the pressure at the top and bottom of the inside kettle is the largest,but the area nearby the paddle wheel has the largest pressure difference ;the turbulent kinetic en-ergy of the flow field increases from bottom to top .