Abstract This study presents the performance analysis of solar air heater in which spring shaped fins introduced beneath the absorber plate are investigated. Effects of spring fin wire diameter ratio, spring diameter ratio and helicoidal pitch ratio on the thermal performance for varying flow rates are analyzed. The results for thermo-hydraulic enhancement factor are studied and it is found that the spring fin produces greater turbulence inside the absorber duct while causing lesser resistance to flow. For varying helicoidal pitch ratio of spring fin, the Thermo-hydraulic enhancement factor and Nusselt number are found to be optimally high for a helicoidal pitch ratio of 0.133 for the entire range of Reynolds numbers. The Nusselt number rises with increase in spring wire diameter ratio. However, the thermo-hydraulic enhancement factor rises with increase in spring wire diameter ratio up to 0.093 and then drops due to higher flow resistance. The Nusselt number drops with increase in helicoidal spring diameter ratio. The thermo-hydraulic enhancement factor is substantially higher at 1.268 for helicoidal spring diameter ratio of 0.06 at lower Reynolds numbers. Correlations are developed for the spring geometric parameters in terms of Nusselt number and friction factor with a deviation of ± 10 % in terms of parity.

中文翻译：

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使用螺旋弹簧形翅片增强热工水力性能的太阳能空气加热器分析-数值研究

摘要 本研究介绍了太阳能空气加热器的性能分析，其中研究了在吸收板下方引入的弹簧形翅片。分析了弹簧翅线径比、弹簧径比和螺距比对不同流量下热性能的影响。研究了热工水力增强因子的结果，发现弹簧翅片在吸收器管道内产生更大的湍流，同时导致更小的流动阻力。对于弹簧翅片的不同螺旋螺距比，发现对于整个雷诺数范围的螺旋螺距比为 0.133，热液压增强因子和努塞尔数最佳地高。努塞尔数随着弹簧线径比的增加而增加。然而，热工水力增强系数随着弹簧线径比的增加而上升，最高可达 0.093，然后由于流动阻力增加而下降。努塞尔数随着螺旋弹簧直径比的增加而下降。在较低雷诺数下，对于 0.06 的螺旋弹簧直径比，热液压增强因子显着更高，为 1.268。根据 Nusselt 数和摩擦系数开发弹簧几何参数的相关性，在奇偶校验方面的偏差为 ± 10 %。