aT ar -Ar-= a,(T, -T ) ( Y = R, z > 0) werden zwei Parameter fur die Beschreibung des radialen Energietransportes verwendet, die radiale Warmeleitfahigkeit der durchstromten Schuttung, A und ein Wandwarmeubergangskoeffizient, a,, der den experimentell beobachteten ,,Sprung" der radialen Temperaturprofile an der Wand beschreiben sol1 ( l / a , ist ein Kontaktwiderstand zwischen Schuttung und Wand). Der EinfluB der axialen Leitung -der Term mit A, in GI. (1)

Gas density affects the gas holdup in bubble columns. Even at atmospheric pressure, different gases produce varying gas holdups. This contribution explores the causes for variations in gas holdups occurring for different gases. Differences in the bubble size distribution resulting from varying rates of bubble breakup and coalescence as well as dissimilar bubble rise velocities are the most likely causes of differences. Correlations that include a term for gas density are able to qualitatively predict the effect of changing gas density, but no correlation can consistently predict the gas holdup for multiple systems.

A pair of Superconducting Septum Magnets are required to permit Hypernuclear Physics Experiments at JLAB's Hall A at angles to the incident beam as small as 6 degrees. A Cold Iron Superconducting " C " magnet design has been selected. This magnet has a central field of 4.23 Tesla at a current density of 25,000 Ampicm2, the stored energy is 0.22 Megajoules and the inductance is 1.0 Henries. The magnet has an effective field length of 0.67 meters, an average gap of 0.25 meters and an average pole width of 0.15 meters. The magnet is currently being fabricated by BWXT Inc. under contract to INFN.Index Terms-Detector magnets, septum magnets, cold iron magnets.

Detailed measurements and computational fluid dynamics (CFD) investigation of the hydrodynamics in a bubble column containing internal features causing flow disturbances are presented for both air and helium gases. An optical needle probe has been used to measure profiles of bubble size, bubble velocity, and gas holdup at different locations across the cross section of the column. An approach combining CFD with population balances is able to represent observed multiphase flow phenomena such as the effect of the pipes to remix and redistribute the gas as well as the tendency of the gas to channel through a slit in the pipes rather than go around the pipes. The comparison of CFD simulation to experimental measurements reveal that the overall decrease in gas holdup observed when switching from air to helium gas can be explained by swarm effects, whereas the steeper decrease in the gas holdup profile across the column is due to coalescence effects. © 2018 American Institute of Chemical Engineers AIChE J, 64: 3764–3774, 2018

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