Pressure drop in monolith reactors

A theoretical model for the computation of pressure drop in bubble-train fl ow inside capillaries of square cross-section was developed. The model is b ased on three contributions: hydrostatics, viscous pressure drop, and capil lary pressure drop. Capillary pressure drop is related to the shape of the fronts and ends of the bubbles. The model does not include entrance or exit effects, has no adjustable parameters, and agrees very well with available experimental data. For a given set of flow parameters, bubble velocity and liquid slug average velocity are computed as a function of gas and liquid superficial velociti es. The length of the unit cell determines the number of bubbles inside the capillary for a given flow situation. The model requires experimental info rmation of average bubble lengths to compute the length of a unit cell cons isting of a bubble and a liquid slug. The three pressure contributions for a unit capillary length are linear fun ctions of the number of bubbles inside the capillary. The length of the bub bles in bubble-train flows is a critical parameter in the computation of pr essure drop. (C) 2001 Elsevier Science B.V. All rights reserved.