This paper proposes T-shaped ribs as obstacles attached to the heat absorber plate in a rectangular solar air heater to promote heat transfer. The thermal and aerodynamic performance of the solar heater was numerically evaluated using three-dimensional Reynolds-averaged Navier–Stokes equations with the shear stress transport turbulence model. A parameter study was performed using the ratios of rib height to channel height, rib width to channel width, and rib width to rib height. The area-averaged Nusselt number and friction factor were selected as the performance parameters of the solar air heater to evaluate the heat transfer and friction loss, respectively. In addition, the performance factor was defined as the ratio of the area-averaged Nusselt number to the friction factor. The maximum area-averaged Nusselt number was found at h/e = 0.83 for a fixed rib area. Compared with triangular ribs, the T-shaped ribs showed up to a 65 % higher area-averaged Nusselt number and up to a 49.7% higher performance factor.

中文翻译：

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太阳能空气加热器中T形障碍物的热性能

本文提出将T形肋作为障碍物附着在矩形太阳能空气加热器的吸热板上，以促进热传递。使用三维雷诺平均Navier-Stokes方程和剪切应力传输湍流模型对太阳能热水器的热和空气动力学性能进行了数值评估。使用肋骨高度与通道高度的比率，肋骨宽度与通道宽度的比率以及肋骨宽度与肋骨高度的比率进行参数研究。选择面积平均努塞尔数和摩擦系数作为太阳能热水器的性能参数，分别评估传热和摩擦损失。另外，性能因子定义为面积平均努塞尔数与摩擦因子之比。发现最大面积平均努塞尔数为h / e = 0。固定肋骨面积为83。与三角形肋骨相比，T形肋骨的面积平均Nusselt数高出65％，性能因子高出49.7％。