Channel voiding

In eontrast, the conventional size channel void fraction data conform to the Ar-mand correlation (1946). To our knowledge, no unusually low void fraction data have been reported for conventional size channels, so the two-phase flow in conven-... 

Thus, similar void fraction data can be obtained in micro-channels and conventional size channels, but the micro-channel void fraction can be sensitive to the inlet geometry and deviate significantly from the Armand correlation. 

A bifurcation cascade with micro channels feeds a wide fixed bed (channel void space for particle insertion), followed by a multitude of catalyst retainers, which act like frits, i.e. support the catalyst particles and prevent their loss [7, 77, 78]. Besides supporting the particles, these parts have a size-exclusion function to the lower size limit of about 35-40 pm. The retainers are followed by an array of elongated channels that serve to build up a uniform pressure drop along the wide retainer bed. Finally, the streams are collected in a bifurcation cascade of identical shape as the feeding cascade, but mirror-imaged in position. 

Liquid-Metal Channel Voiding and Expulsion Models 297... 

This equation shows that R is given by the ratio of particle displacement velocity V to average carrier velocity , or equivalently to the ratio of channel void volume V° to the retention volume V. Thus R is experimentally accessible because V is the measured volume required to displace a given particle size" through the channel. However, the equation also shows that R is related to X, which is related to d through the previous equation. Thus a linkage is formed between particle diameter d and experimental retention volume V. It has been estimated that particle diameters accurate to 1-3% can be obtained by using this approach (2). 

Fig. 6 Porphyrin zeolite analogue utilizing the MTCPP building bloeks. along with bipyridyl and external metal ion auxiliaries. The nearly 1 nm-wide channel voids propagate in the erystal in two perpendicular directions parallel to the porphyrin planes. (View this art in color-at www.dekker.com.)...

Porous stractures (Fig. 4.4b) typically consist of irregularly shaped voids with interconnecting channels (voids). The pore size, porosity (the fraction of void... 

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