Thermo-mechanical analysis of a porous volumetric solar receiver subjected to concentrated solar radiation

The damage caused by high working and non-uniform temperature distributions is one of the major obstacles to the development of receivers exposed to concentrated solar radiation. The thermal and mechanical performance of a typical porous Silicon Carbide volumetric receiver with foam structure is investigated in the present study with a coupled thermo-mechanical model. The developed model includes coupling of fluid flow, thermal and mechanical models to determine flow field, temperature and stress distributions. The main objective is to investigate the effects of various geometric, structural and design parameters on the absorber's thermal and mechanical performance and to identify the failure-prone regions when the absorber works under steady-state conditions. The effects of porosity, pore size, inlet velocity, absorber's geometrical dimensions, and incident solar flux distribution on the receiver's performance are investigated in detail. It is observed that higher po-rosities, pore sizes and inlet velocities result in lesser thermal stresses in the porous absorber. The uniformity of the incident radiation flux also reduces thermal stresses and improves the absorber's performance. The near-wall region at the inlet is found to be most prone to mechanical failure. The results of the study provide important conclusions to help in the selection of the proper set of parameters that ensure the efficient, safe and reliable working of the receiver.