Experimental correlations for Nusselt number and friction factor in a flat solar air collector equipped with triangular-rectangular ribs

IF 2.6 3区工程技术 Q2 ENGINEERING, MECHANICAL

International Journal of Heat and Fluid Flow Pub Date : 2025-04-28 DOI:10.1016/j.ijheatfluidflow.2025.109860

Nacer Chouchane , Hammam Chouchane

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引用次数: 0

Abstract

This study investigates the impact of rib configuration on heat transfer and pressure losses in flat air collectors. Various rib shapes, including rectangular-triangular configurations arranged in inline and staggered patterns, were tested by varying geometric parameters such as rib inclination (30°, 60°, 150°, 120°), spacing between rib rows (5 cm, 7 cm, 10 cm), rib length (5 cm, 10 cm), pitch between rib peaks (12.5 cm, 14.166 cm), pitch between holes (11.7 cm, 12.1 cm, 13.366 cm), hole diameter (0.4 cm, 0.8 cm), and spacing between adjacent ribs (2.5 cm, 9.166 cm).

Experiments were conducted for Reynolds numbers ranging from 1000 to 12,000 for dynamic studies and from 3000 to 20,000 for thermal studies. The results demonstrated that staggered rib configurations significantly enhanced thermal performance, with Nusselt numbers increasing by up to 95 % at Reynolds numbers of 19,500. Smaller rib row spacings (e.g., 5 cm) improved thermal efficiency by up to 45 %, though this also led to an increase in pressure losses from 5 Pa to 45 Pa, depending on rib angle and spacing.

Numerical models were developed using the Vaschy-Buckingham π theorem, allowing the derivation of empirical correlations to aid in selecting optimal rib configurations for various thermal systems. These findings provide a deeper understanding of the influence of rib geometry on heat transfer and pressure loss and offer practical guidelines for optimizing the performance of solar thermal collectors.

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带三角-矩形肋的平板太阳能空气集热器中努塞尔数与摩擦因数的实验相关性

本文研究了肋形结构对板式空气集热器传热和压力损失的影响。通过不同的几何参数，如肋倾角（30°、60°、150°、120°）、肋排间距（5 cm、7 cm、10 cm）、肋长（5 cm、10 cm）、肋峰间距（12.5 cm、14.166 cm）、孔间距（11.7 cm、12.1 cm、13.366 cm）、孔直径（0.4 cm、0.8 cm）和相邻肋间距（2.5 cm、9.166 cm），测试了不同的肋形，包括以直线和交错方式排列的矩形-三角形构型。动力学研究的雷诺数范围从1000到12000，热研究的雷诺数范围从3000到20000。结果表明，交错肋结构显著提高了热学性能，当雷诺数为19,500时，努塞尔数增加了95%。较小的肋排间距（例如5厘米）可将热效率提高45%，但这也会导致压力损失从5 Pa增加到45 Pa，具体取决于肋排角度和间距。利用Vaschy-Buckingham π定理建立了数值模型，允许推导经验相关性，以帮助选择各种热系统的最佳肋结构。这些发现提供了对肋形几何对传热和压力损失的影响的更深入的理解，并为优化太阳能集热器的性能提供了实用指南。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Heat and Fluid Flow 工程技术-工程：机械

CiteScore

5.00

自引率

7.70%

发文量

131

审稿时长

33 days

期刊介绍： The International Journal of Heat and Fluid Flow welcomes high-quality original contributions on experimental, computational, and physical aspects of convective heat transfer and fluid dynamics relevant to engineering or the environment, including multiphase and microscale flows. Papers reporting the application of these disciplines to design and development, with emphasis on new technological fields, are also welcomed. Some of these new fields include microscale electronic and mechanical systems; medical and biological systems; and thermal and flow control in both the internal and external environment.