Experimental and Numerical Study of the Thermal Behavior of Clips in Concentrated Solar Tower Receivers

In this study, we investigated the thermal behaviour of a guiding support, referred to as a clip, for a tube resembling those used in solar central receivers. The focus is on the clip's heating process, which occurs when molten salt begins to flow inside the receiver tube. This work involves both experimental measurements and numerical simulations of the clip, which can be considered as a fin attached to the tube. Experimentally, we measured the temperature profile of the clip over time and observed that, despite the characteristic decaying exponential shape of the clip, the heat transfer can be approximated as one-dimensional. Moreover, numerical simulations were performed to gain a better understanding of the clip’s thermal response. By comparing the simulation results to the experimental data, we were able to determine the most suitable boundary condition for the clip end, which is attached to the receiver's supporting structure. Furthermore, the experimental data was compared to an analytical solution for the temperature evolution of a fin that took into account the cooling effect of natural convection and radiation, yielding a maximum error of 8%.