基于PIV的仿生鲸尾型搅拌桨反应器流场研究

On Flow Field of a Bionic Whale Tail Turbine Agitator Based on PIV

为增强搅拌反应器混合性能,本文基于仿生学思想,设计了一种鲸尾型搅拌桨,即WTT搅拌桨(Whale tail turbine),运用2D-PIV设备进行流场研究.结果表明:WTT搅拌桨相比RT(Rushton turbine)搅拌桨,可以提高流体的最大径向速度以及搅拌罐下部流体的轴向速度,而且远离桨叶时,轴向速度的提高更加明显;WTT搅拌桨和RT搅拌桨都是径向流搅拌器,WTT搅拌桨可以产生更大的速度,能促进流体的混合和能量的传递,还可略微提高搅拌罐底部流体的湍动能,其产生的轴向速度和径向速度的最大Lyapunov指数均大于RT搅拌桨,即WTT搅拌桨产生的流场混沌程度更高,混合性能更好.

In order to enhance the mixing performance of stirred reactors,a whale tail turbine(WTT)was proposed based on the idea of bionics,and the bionic design was proceeded,in addition,the flow field experiments were carried out by mean of 2D-PIV equipment.The results show that WTT impeller can improve the maximum radial velocity and axial velocity at the bottom of the tank compared with the RT impeller,and the enhancement of axial velocity is more obvious when the impeller is far away from the impeller.The WTT and RT are both radial flow agitators.The WTT impeller can generate larger velocity,which can promote the mixing of fluid and the transfer of energy.The WTT impeller can slightly improve the turbulent kinetic energy of fluid at the bottom of the agitator tank.The largest Lyapunov exponent of axial velocity and radial velocity generated by the WTT impeller is greater than that of the RT impeller,which means that the flow field generated by the WTT impeller has a higher degree of chaos and better mixing performance.