水平四葉伝熱管内凝縮熱伝達に関する研究

抄録

This study deals with condensing heat transfer in a quadrilobed tube. HFC-134a was used as the working fluid. The effect of the tube configuration on the heat transfer coefficient was evaluated in horizontal flow. Superheated vapor or wet vapor was supplied to the condenser, and heated in water. A straight and twisted quadrilobed tubes were used. The local heat transfer coefficient at the center in the length was evaluated from the wall temperature measured by mounted thermocouples. As the result, for low refrigerant mass flux in the straight tube, deterioration in local heat transfer coefficient under low quality condition was suppressed, because condensate might be accumulated along the center by surface tension. For the twisted tube, on the other hand, heat transfer coefficient was lower than the straight one. In this experiment, since the twist tube improved the water heat transfer, the twist tube produced higher heat transfer rate than the straight one.