本研究在掃流微過港、中通入氣體，探討液體速
度、氣體流量以及過濾壓差等操作條件對過濾通量、粒
子附著機率、濾餅性質以及濾面上剪切力的影響。隨著
氣體流量的提昇會形成不同的流態，在氣i包流動的範圍
內，作用於朕面上的剪切力能有效抑制品昌、餅生成，並且
可以提高濯速，但隨著流態由氣泡流動轉變為團狀流，
剪切力迅速增加的結果，會造成粒徑5μm 以上的粒子
之附著大幅減少，在小粒子填補空隙後導致孔隙度下
降，與流體對濾、餅壓縮的雙重作用下，使得過是、比阻出
現明顯的增加，濾、速反而比未通氣時的數值低。配合力
分析的結果可以發現，氣體對粒子造成的作用力在過濾
中扮演桂重要的角色。本研究所提出基於力分析的粒子
附著機構，可以用來預測濾餅中之粒徑分佈，粒子之附
著機率與濾餅性質。The effects of liquid velocities, gas velocities
and filtration pressures on the filtration flux, particle
deposition probability, cake properties and shear stress on
the membrane surface in air-sparging cross-flow
microfiltration are studied. The flow pattern plays an
important role on the filtration performance. The shear
stress on the membrane surface can efficiently reduce the
cake mass and enhance filtration rates under bubble flow;
however, the specific filtration resistance of cake will
markedly increase, which results in a lower filtration rate
than non-sparging gas condition, under a slug flow. It is
because the rapid increase in the shear stress on the
membrane surface leads the stability of larger particles to
decrease in a slug flow and also leads more small particles
to pack in the void in cake. The cake layer is compressed
more seriously due to the gas-flow, this make the specific
filtration resistance of cake to be significantly increased.
According to the force analysis, the probability of particle
deposition on the membrane surface can be understood.
Therefore, the cake mass, the particle size distribution in
cake can be also estimated.
關聯:
2008年輸送現象及其應用研討會論文摘要集 ( 2008 Symposium of transport phenomena and applications abstract book)
