Thermal gradients - evaluations for the receiver of a disc solar concentrator

The receiver of a disc solar concentrator is not only stressed by the high solar radiation concentrated in a limited volume; it must also cope with thermal fluctuations. The resulting thermal gradient has a catastrophic effect on the mechanical characteristics of the receiver. As the thermal gradient increases, the thermal stress on the selected materials increases. If the creep limit is exceeded, the material begins to deform plastically to the point of fracture. The outputs of the problem are the spatial trend of the temperature at the end of the transient and the temporal trend of the most stressed section, which turns out to be the output section. In addition, the thermal stress induced by the temperature gradient was evaluated at the end of the transient, which turns out to be the most extreme working condition. The following materials were studied: Alloy 625, Alloy 800H, Haynes 230, Inconel 740H, Alloy 316H. The best material is Inconel 740H, which has a high yield strength and the lowest ΔT of all the materials analyzed. It is also the only one that could withstand the induced thermal shock even under extreme working conditions.