Two-Phase Flow in Ceramic Monoliths

In a follow-up study, Koptyug et al. 115) reported images of both liquid and gas flow and mass transport phenomena in two different cylindrical monolith catalysts (one with triangular channels, the other with square channels) at various axial locations within the monolith. Heibel et al. 116,117) addressed two-phase flow in the film flow regime and reported investigations of liquid distributions in the plane perpendicular to the direction of superficial flow, in particular, addressing the accumulation of liquid in the corners of the square channels of the monolith. 

Two successive 2-D xz images of two-phase flow through the parallel channels of a ceramic monolith rated at 400 cpsi, for a gas flow rate of 200 cm min (a) 74ms after excitation, (b) 220 ms after r.f. excitation. In-plane image resolution is 393 pm (x) x 783 pm (z). Reprinted from reference (84) with permission of Springer Science and Business Media. 

we see that in a single image acquisition, the line excitation SEMI-RARE method allows an evaluation of the extent of flow heterogeneity (up- and downflow) within the monolith. Furthermore, velocities in completely liquid field channels can be measured. This was not possible when SEMI-RARE was used because velocities were measured by following a gas-liquid interface. However, a limitation of the line excitation SEMI-RARE technique is that there needs to be a significant amount of liquid present within the monolith, because the gas phase is not imaged only liquid captured in the initial line excitation can be followed. 

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Fig. 38. Line excitation SEMI-RARE images of two-phase flow in a ceramic monolith rated at 200 cpsi. The signal intensity shows how far the initially excited water molecules have traveled in the period between line excitation and the image acquisition. The gas flow rate was (a) 0, (b) 100, (c) 200, and (d) iOOcin inin. Images acquired 78ms after r.f. excitation are shown. A 5mm-high slice of spins was initially excited along the direction of flow. The fleld-of-view is 50 mm (x) x 25 mm (z).

J.J. Heras, A.J. Sederman, LF. Gladden, Ultrafast velocity imaging of single- and two-phase flows in a ceramic monolith. Magnetic Resonance Ima ng, 2005, 23, 387-389. 

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