突起を有する平板上を流下する液膜の数値計算

摘要

化学装置においては液膜内に気体を吸収させること がよくある．吸収冷凍機の吸収器もその一つであり， 吸収器においては吸収液を冷却した伝熱面上に流下さ せ，液膜中に蒸発器から流れてくる冷媒蒸気を吸収さ せている．%Vertical plates or vertical tubes are used as absorber surface in certain type of absorption chiller. Regularly spaced protrusions would be necessary on their surface to cause mixing within the liquid film flowing over them to promote absorption. To determine the most suitable form of the protrusions experimentally takes much time due to so many possible combinations of parameters. It is convenient from the point of designing to replace them by computer simulations. So numerical calculations are tried using CIP method for the most part and Level set method for the treatment of film surface. Parameters concerning rectangular protrusions such as height h, width ω and interval s are varied to study their effect on the flow patterns. Flow rates are also varied between 1 000 and 2 000 in film Reynolds number. It was found that for s/h ＝ 3 a single circulation vortex is formed between fins and for s/h = 6 two completely separate vortex is formed for all Reynolds numbers studied.