435 流下液膜式プレート型吸収熱交換器の開発 : 界面活性剤添加の影響(省エネルギー(III))(空気調和・冷凍技術)

概要

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Influences of a surfactant on performance of a novel plate type absorber have been investigated experimentally. Experiments were conducted on the vertical flat plate type absorber for absorption refrigerator/chiller, with changing surfactant's concentration. Surfactant(n-octanol) concentration was varied in the range of 0〜100ppm. Temperatures of LiBr aqueous solution, cooling water and heat transfer surface were measured minutely. Furthermore, flow conditions of LiBr aqueous solution were continuously observed optically by using a high-speed video camera. Refrigerating capacities were calculated from those measurement results. Results showed that absorber performances were significantly enhanced with increase of surfactant concentration. In case of surfactant concentration is 100ppm, absorber performance became about double than that case of no surfactant. Also, many protuberant "ropey" flows of LiBr aqueous solution were observed at upper region in the plate. These ropey flows swung side to side horizontally with a frequency of about 10 hertz. Consequently, it has been confirmed that those improvement were caused by the occurrence of Marangoni convection in the solution flow when the surfactant was added.
2001-07-09