螺旋肋片形成非衰减性旋流的强化传热性能

HEAT TRANSFER ENHANCEMENT CHARACTERISTICS OF NON-DECAYING SWIRL FLOW DUE TO SPIRAL FIN

对于螺旋肋片形成非衰减性旋流的传热和阻力特性进行了实验研究 ,并比较分析了非衰减性旋流与多翅管和衰减性旋流在传热和阻力特性方面的差异 .研究结果表明 ,在传热系数上非衰减性旋流比多翅管和衰减性旋流分别提高 6 0 %～ 85 %和 4 9% ,但非衰减性旋流的阻力损失也明显高于多翅管和衰减性旋流 .综合热力性能的分析结果表明 ,在较低Reynolds数下非衰减性旋流的综合热力性能较好 ,当Reynolds数大于某一临界值 (本实验为 180 0 0 )

The heat transfer enhancement and flow resistance characteristics of non-decaying swirl flow formed by a spiral fin tube is investigated experimentally in this paper. The effects of non-decaying swirl flow, decaying swirl flow and non-swirl flow on heat transfer and resistance characteristics are also compared and analyzed. The experimental results indicate that heat transfer coefficient of non-decaying swirl flow increases by 60%～80% compared with non-swirl flow and by 49% compared with decaying swirl flow, but the pressure drop of non-decaying swirl flow is obviously higher than that of decaying swirl flow and non-swirl flow. The analysis results show that the comprehensive thermal property of non-decaying swirl flow is better than that of decaying swirl flow at a low Re, when Re is larger than a critical value (Re=1.8×10 4 in this experiment) the decaying swirl flow is better.