| This Ph D thesis combined CFD method and theoretical models to systematically investigate hydrodynamics of a self-developed structured packing,Winpak.Mathematical models were established to describe the dry pressure drop and liquid distribution from a multiscale perspective.Dry pressure drop,as the benchmark of wet pressure drop,is related to energy consumption and capacity.This paper studied the mechanism and optimization of the dry pressure drop within Winpak.The contribution of the dry pressure drop was decomposed into two components,and the effect of packing geometry on the dry pressure drop was investigated by CFD simulations.Simulation results show increasing the cutting angle could effectively reduce the dry pressure drop.In addition,with the combination of simulation results and an existing theoretical model,a set of correlations was developed to predict the dry pressure drop of entire column.An average relative error of 6.9% proves the availability of the predicting model.To a certain extent,the liquid distribution could decide the mass transfer performance of a separation process in a packed column.Therefore,on the basis of the study on 350Y-type corrugated structured packing,a multiscale method was developed combining CFD method and unit network model to connect the local hydrodynamics of 350Y-type Winpak with its macroscopic liquid distribution.First,in view of Winpak’s structure,6 REUs were built for CFD simulations to obtain the local liquid holdup,effective wetting area,and the liquid distribution coefficients of the packing.Then,a unit network model was developed based on the distribution coefficients to describe the liquid distribution within the packing.Results show that liquid film split by the window leads to the increase of liquid holdup and effective wetting area,as well as to the mitigation of the tendency of liquid flowing toward the sidewall.In addition,three typical flow patterns appear under different operation conditions,wherein the appearance of the chaos flow formed in the 1st REU indicates the occurrence of a flooding phenomenon. |
