Abstract:

Numerical simulation on slit finned elliptical tube heat exchangers with different transverse tube pitch S₁, longitudinal tube pitch S₂ and the ratio a/b of major and minor axis of the elliptical tube, was verified by model experiment. The effect of tube bundle structure on the heat transfer and resistance characteristics of slit finned elliptical tube heat exchangers was analyzed. The results indicate that as S₁ decreases from 70.55 mm to 60.55 mm, Nu and Eu at air-side increase, with optimized comprehensive flow and heat transfer performance of the heat exchangers when S₁ equals to 60.55 mm. As S₂ decreases from 75 mm to 65 mm, Nu at air-side increases, but Eu at air-side has no significant changes, with optimized comprehensive flow and heat transfer performance of the heat exchangers when S₂ equals to 65 mm. The heat transfer and resistance characteristics of slit finned elliptical tube heat exchangers are significantly influenced by the transverse tube pitch. When the elliptical tube circumference is equal and a/b is between 1.5 and 2.5, the optimized comprehensive flow and heat transfer performance of the heat exchangers was the best when a/b was 1.8. The findings of this paper provide proofs of the application and further optimization of such heat exchangers in engineering practice.

Key words: slit finned elliptical tube heat exchangers, numerical simulation, modeling experiment, heat transfer, optimization

摘要：

在模化试验验证的基础上，对不同横向管间距S₁、纵向管间距S₂和椭圆管长短轴比a/b的开缝翅片椭圆管换热器进行了数值模拟，分析了管束结构的差异对开缝翅片椭圆管换热器性能的影响。结果表明：横向管间距在60.55～70.55 mm范围内，空气侧Nu和Eu均随S₁减小而增大，S₁为60.55 mm时换热器综合流动传热性能最好；纵向管间距在65～75 mm范围内，空气侧Nu随S₂减小而增大，Eu变化不明显，S₂为65 mm时换热器综合流动传热性能最好；横向管间距对开缝翅片椭圆管换热器传热、流动性能的影响较纵向管间距更为明显；在等周长条件下，椭圆管长短轴比a/b在1.5～2.5范围内，a/b为1.8时换热器综合流动传热性能最好。研究成果可为此类换热器在工程实际中的应用与进一步优化提供依据。

关键词: 开缝翅片椭圆管换热器, 数值模拟, 模化试验, 传热, 优化