蒸発器管内冷媒の流動特性と熱輸送を考慮した 冷蔵庫除霜運転の効率向上に関する研究

－第1 報：単列モデルによる冷媒の基本流動特性の評価－

抄録

In a household refrigerator, defrosting of a frosted evaporator is effective to improve performance of the refrigerator. Many studies on defrosting have been made for air-side heat transfer. On the other hand, there are few researches on heat transfer inside the evaporator tube, that is, the effect of heat transport with refrigerant flow on defrosting. In the present study, refrigerant vapor-liquid two-phase flow inside single-row test sections of aluminum tube, visualization tube and aluminum fin-tube model simulating the refrigerator evaporator was examined under heating condition. During heating, refrigerant liquid in the bottom part was pushed up to upper part of the test section by vapor generated in the lower part. But some liquid returned, so liquid continued remaining in the bottom part. As time passed, dryout came out from top to bottom of the test section in sequence. Such refrigerant flow characteristics were discussed with measured changes of refrigerant pressure and temperature and tube wall temperature.