离心力场对微滤膜过滤强化的机理研究

The research of the enhancement of membrane microfiltration is an advanced researeh of the membrane technology. The enhancement of a tubular microfiltration membrane by a rotating crossflow is a brane-new idea. The results of this project has proven, that the centrifugal force field of a rotating crossflow can enormously lighten the concentration polarization and membrane deposit phenomena during membrane filtration process. Then, the membrane permeating flux is increased greatly and the energy corsuming is reduced also. This research has ascertain the complete picture of flow field in the annular gap of a tuburar microfiltration membrane separator. The existense of the vortices resembling to the Taylor vortices has been verified. The velocity and pressure distributions of main flow were decided in numerical quantities. Using FLUENT6 commercial software a numerical simulation about three dimensional rotating flow field in the membrane separator was done successfully. The filtration tests and power consumption analyses have proved increases of both permealing flux and efficency intensely. The mathematical models for the separator were derived. And the main factors determining permeating fluxes of microfiltration were given. For given flux and pressur drop, the critical particle sizes, that could not enter the boundary on the membrane surface or could not deposite in the boundary, were determined by analyzing the motion of partides and forces exerted on them. Then the new knowledge on the mechanism of microfiltration enhancement by a rotating flow has been obtained. And it provides a profound theoretical base for engineering design of high efficient membrane separators with rotaling crossflow.

把理论分析、实物测定和数学模型计算紧密结合，研究旋转横向流对管式微滤膜过滤强化的机理，探索膜器环隙中流场全貌、压力分布和膜面及其附近固体颗粒的行为。据此确定在切向主流、法向渗透流和旋转流的离心力场作用下粒子的受力与平衡，以及沉积与迁移条件，认识膜面滤饼形成过程和影响因素，建立数模，为高通量的旋转横向流膜器设计提供依据。