静電植毛したクロスフィンチューブ熱交換器におけるフィン上液膜の観察および蒸発熱伝達特性

<p>To improve and maintain the refrigerant wettability of the evaporative heat transfer surface and improve the evaporative heat transfer performance from the thin liquid film, we focused on the fiber flocked heat transfer surface where rayon fibers were electrostatically flocked onto the surface of a cross-fin type heat exchanger. In this study, to clarify the shape of the liquid film formed on the flocked surface and the evaporative heat transfer characteristics, this heat exchanger was immersed in water refrigerant and the liquid film on the fin was observed. It was confirmed that two types of liquid films were formed, a bridge liquid film extending between the fins and an inter-fiber liquid film on the fin surface. Then, a method for estimating the thickness of both liquid films was proposed, and its validity was confirmed. Next, comparative experiments on non-flocked surfaces confirmed that the flocked surface did not inhibit heat transfer. Furthermore, it was found that when the fin surface was covered with the inter-fiber liquid film, the thermal resistance was reduced to about half that of the non-flocked surface. Finally, we proposed a model for predicting the thermal resistance of the inter-fiber liquid film and confirmed its application range.</p>