ABSTRACT

In this experimental thermal performance investigation, we present a solar air heater design exhibiting a wavy channel embedded with porous media to illustrate the enhanced fluid mixing and heat transfer area, and consequently high thermal performance. In this design, two wavy plates form the air flow channel and wiremesh as a porous media of high porosity is inserted in the wavy channel to maintain the channel porosity. Results of the investigation revealed promising scope for thermal performance enhancement. Thermal and thermohydraulic efficiency of 38–93% and 38–89%, respectively, is obtained for the investigated range of Reynolds number $\left(2000\le Re\le 11000\right)$ and channel porosity ($97\mathrm{\%}\le \varphi \le 100\mathrm{\%})$. Moreover, the obtained result of thermal and thermohydraulic efficiency for 97% channel porosity is 27% and 24%, respectively, high compared to 100% channel porosity. As a part of this work, we also presented the developed correlations for Nusselt number and friction factor to predict the thermal performance of wavy absorber plate embedded with porous media and the effect of Darcy number on the thermal performance.

摘要

在本实验热性能研究中，我们展示了一种太阳能空气加热器设计，该设计展示了嵌入多孔介质的波浪形通道，以说明增强的流体混合和传热面积，以及由此产生的高热性能。在这种设计中，两个波浪形板形成气流通道，丝网作为高孔隙率的多孔介质插入波浪形通道中以保持通道孔隙率。调查结果揭示了热性能增强的前景。对于雷诺数的研究范围，分别获得了 38-93% 和 38-89% 的热效率和热工水力效率$\left(\mathrm{2000年}\le \mathrm{电阻}\mathrm{电子}\le 11000\right)$ 和通道孔隙率（$97\mathrm{\%}\le \phi \le 100\mathrm{\%})$. 此外，与 100% 的通道孔隙率相比，97% 通道孔隙率的热效率和热工水力效率的结果分别为 27% 和 24%。作为这项工作的一部分，我们还提出了 Nusselt 数和摩擦系数的相关关系，以预测嵌入多孔介质的波浪形吸收板的热性能以及达西数对热性能的影响。