Falling film flow of ionic liquid-MEA solution on vertical cooling flat plate and channel

Abstract

Visualization experiments on heated Ionic liquid-MEA mixed solution falling film flowing on a uniformly cooled vertical plate and channel (plate with two sidewalls) by using an IR thermal camera were performed for the first time. The effects of the wall-liquid temperature difference and the liquid flow rate on the falling film flow pattern, film width and area were discussed. It is evidenced that the Marangoni effect exists in a channel and has brought quite different flow patterns of the falling film from the plate because of the corner effect. Instead of a string film along the central area of the plate on a flat plate, the falling film presented two wetted strips at the wall corner on a channel because of larger capillary force. A symmetrical and asymmetrical film expansions were presented on the plate and channel, respectively, with the increasing wall-liquid temperature difference. The widest film width and largest film area were reached at a wall-liquid temperature difference of 40 °C and liquid flow rate of 600 mL/min.