Abstract Solar air heater (SAH) is a device used to convert sun radiations into heating applications. To improve its performance, the heat absorbing side of SAH is modified with the ribs called roughness. The flow characteristics and augmentation of heat due to square shaped ribs in SAH having triangular cross-sectional passage has been simulated using computational fluid dynamic (CFD) technique. The CFD simulations consisted of design and modeling of SAH. Two different roughness parameters has been considered in the analysis i.e. relative roughness pitch (P/e) and relative roughness height (e/D) and their value ranges from 5 to 13 (in four sets) and 0.013 to 0.05 (in four sets), respectively for Reynolds number varies from 3900 to 17900. Better augmentation of heat has been seen in SAH by providing ribs on the absorber plate. The highest improvement in heat transfer is seen of the order of 97% in P/e value of 10 and e/D value of 0.05 at Re of 17900. The thermohydraulic performance parameter (TPP) is also calculated and have highest value of 1.97 for P/e value of 10 and e/D value of 0.05 at Re of 17900. Correlation has been developed for both friction factor and Nusselt number based on observed results.

中文翻译：

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基于计算流体动力学的肋状三角风道太阳能空气加热器性能改进与摩擦系数与传热相关性的发展

摘要 太阳能空气加热器 (SAH) 是一种用于将太阳辐射转化为加热应用的装置。为了提高其性能，SAH 的吸热面采用称为粗糙度的肋条进行了改进。已经使用计算流体动力学 (CFD) 技术模拟了由于具有三角形横截面通道的 SAH 中的方形肋条引起的流动特性和热量增加。CFD 模拟包括 SAH 的设计和建模。分析中考虑了两个不同的粗糙度参数，即相对粗糙度节距（P/e）和相对粗糙度高度（e/D），它们的值范围为5至13（四组）和0.013至0.05（四组） ，雷诺数分别从 3900 到 17900 不等。通过在吸收板上提供肋，在 SAH 中可以看到更好的热量增加。