为降低多孔介质吸热器辐射散热损失，设计了一种石英玻璃套管与多孔介质吸收系数阶梯增加双层吸热器，该吸热器通过石英玻璃套管回收部分红外热辐射损失，同时均化非均匀聚集太阳能热流密度降低吸热峰值温度，提高吸热效率和吸热安全。采用耦合传热数值计算与实验验证相结合手段，对双层吸热器聚集太阳光热转换特性进行研究。结果表明：与单层多孔介质吸收器相比，在流体质量流量3~10g/s范围内双层吸热器热效率较单层提高约5.8%~11.2%；非均匀等比型速度入口与高斯聚集太阳光匹配性更好，热效率较均匀速度入口增加约3.1%。此外，增加玻璃套管长度、减小其壁厚，和减小孔隙直径等结构调整，均有益于吸热器热效率的提高。

A porous solar receiver consisting of glass multi-tubes and a porous absorber was proposed to reduce re-radiation loss. The thermal conversion performance was assessed through combined numerical heat transfer analysis and experimental measurements. Results indicate that the thermal efficiency of the double-layer solar absorber is approximately 5.8% to 11.2% higher than that of the monolayer absorber when the mass flow rate varies from 3.0 g/s to 10 g/s. Since the double-layer design is more suitable for Gaussian-shaped concentrated solar flux, the thermal efficiency with a non-uniform velocity inlet is about 3.1% higher than with a uniform velocity inlet. Additionally, the thermal efficiency increases with longer quartz glass multi-tubes but decreases with thicker tube walls and larger pore diameters. These findings provide valuable support for the development of a porous solar receiver.

TK513.5

国家自然科学基金(52176181)