Abstract: Experimental study of flow pattern and liquid velocity distribution by the tracer technique in a two-meter diameter single pass sieve half-tray using air-water system reveals that there exist highly non-ideal flowing behavior. Typical residence-time distribution curves covering the whole tray deck are presented, from which four flow regions can be observed, a main channelling region of non-uniform flow, a sideway region of accompanied subsidiary flow, a small region of backward flow and a complete mixing region next to the inlet weir. The tray models available in the present literature seem incapable to simulate all these complicated hydrodynamic phenomena in a large tray. An eddy diffusion model with consideration of non-uniform liquid velocity field has been developed from the basic partial differential equation of mass transfer by introducing a velocity distribution function j. Since the experimental liquid velocity profile follows approximately the exponential rule, function j can be taken in similar form with two experimentally determined constants which are dependent on the flowing condition. The non-linear partial differential equation is solved by the method of finite element. For this purpose, the equation should be transformed into elliptic form by mullipying an integrating factor (B) which is equal to exp[PejZ] where Pe is Peclet number and Z is dimensionless flow length. A computer program is designed according to this method to predict numerically the concentration profiles in the whole tray deck as well as the Murphree tray efficiencies under various operating conditions. Typical computed results are presented and discussed.

摘要： 本文介绍了直径为2m的半圆筛板塔试验装置,并得出塔板上液体流动型式和速度分布的一些实验数据。结果表明塔板上存在着相当复杂的流动和分区。 根据实验结果,在本文描述流动的微分方程中,引入了速度分布函数,并成功地用有限元素法来求解传质问题,从而得出了在不均匀的速度场下大型塔板上的液相浓度分布以及塔板效率。