| 摘要 |
PROBLEM TO BE SOLVED: To provide a heat transfer pipe with a grooved inner face using R32-R125 mixed refrigerant (R410A, e.g.) as refrigerant for improving heat transfer performance while avoiding excessive pressure loss of the mixed refrigerant even when the heat transfer pipe with the grooved inner face is longer. SOLUTION: The heat transfer pipe with the grooved inner face having an outer diameter D of 6-10 mm uses the hydrofluorocarbon mixed refrigerant. It comprises spiral grooves and a plurality of fins formed between spiral grooves on the inner face of the pipe . Herein, a groove lead angleθis over 30°but 55°or smaller, a groove depth h is 0.10-0.35 mm and a fin peak angleδis 5-30°. A coefficientαcalculated fromα=S×cosθusing a cross section S of one groove and the groove lead angleθis 0.05-0.10, and a coefficientβcalculated fromβ=L×cosθusing a wetted perimeter L of all periphery and the groove lead angleθis 27-40. COPYRIGHT: (C)2005,JPO&NCIPI
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