聚酯反应釜中流场的模拟与实验研究

Simulation and experimental research on flow fieldin polyester reactor

对聚酯合成工业中的框式组合桨等比例缩小建立模型,基于计算流体力学(CFD)对该双层组合桨搅拌槽内流场进行模拟研究,并利用粒子成像测速(PIV)技术对模拟结果进行验证。搅拌槽内的速度由0.2 m/s变化到1.1 m/s的过程中,搅拌桨桨叶前方和后方的速度等值面同时向框式桨的叶端靠近,随着离底间距(C_(1))增大,搅拌槽上部区域的速度更加均匀,搅拌轴下方的低速区域逐渐缩小,搅拌槽底部的平均速度更加均匀。模拟和实验对比研究结果表明:离底距的增加使搅拌槽的上部和底部逐渐产生小的涡旋,利于上部和底部区域间的物料混合,但不利于槽内整体的物料交换。研究结果可为框式组合桨应用于聚酯反应实际工程提供参考。

The polyester reactor equipped with frame type combined impeller is scaled down and its calculation model is established.The flow field in the stirred tank was numerically investigated based on CFD simulation and the simulation results were validated by PIV experiments.As the speed isosurface changes from 0.2 m/s to 1.1 m/s,the speed isosurface in front of and behind the paddle blades approaches the blade end of the frame paddle at the same time.With the increasing of C_(1),the range of the low-speed area below the mixing shaft gradually decreases,and the average speed at the bottom of the stirred tank is more uniform.The comparative study of simulated and experimental flow charts shows that the increase of the distance from the bottom causes a small vortex on the top and bottom of the stirring tank,which is beneficial to the mixing of materials between the upper and bottom regions,but it is not conducive to the overall material exchange in the tank.The research results provide a reference for the application of the frame type combined impeller in the practical engineering of resin polymerization reaction.