Numerical simulation of convective heat transfer coefficient in wire mesh absorbers with fixed porosity

Abstract

Convective heat transfer is one of the main thermal mechanisms in volumetric absorbers technology. There is a lack of literature on the behaviour of convective heat transfer in dense wire meshes. In this research, numerical simulations are used to determine the influence of geometrical parameters of dense wire meshes, such as wire diameter and mesh count, in obtaining the local volumetric Nusselt coefficient. In order to achieve that aim, a sensitivity study of the inlet air velocity (0.5–5 m/s) and wire temperature (700 K, 1100 K and 1500 K) has been performed with different staggered stacked wire mesh configurations. The fixed single screen and staggered porosity of the studied configurations are 80% and 64% respectively, however the wire diameters in each configuration range from 0.1 mm to 0.7 mm. As a result of this study, the effect of the convection heat transfer is more emphasized in larger wire diameters than in smaller ones. In summary, the flow and heat transfer can be modified without changing the porosity.

Keywords

• Volumetric absorbers
• Volumetric receivers
• CFD simulations
• Heat transfer coefficient
• Central receiver system