Thermal performance of a solar volumetric receiver using the two-energy equation model and radiation boundary condition

Abstract

This work presents numerical results for the thermal performance of a Solar Volumetric Receiver (SVR). The Thermal Non-Equilibrium Model and Rosseland approximation were used. Radiation boundary condition was implemented at the absorber inlet. The numerical technique employed for discretizing the governing equations was the control volume method with a boundary-fitted non-orthogonal coordinate system. The SIMPLE algorithm was used to handle the pressure-velocity coupling. Effects of inlet velocity (uin), porosity (ϕ), medium permeability (K), and thermal conductivity ratio (ks/kf) on the solid and fluid temperatures were investigated. Reduction of temperatures as porosity increases or thermal conductivity decreases was observed, in addition to an increase in entry length for lower porosities or higher thermal conductivity ratios. Increase in inlet solid temperature as permeability increases was accompanied by a longer entry length and reduced final equilibrium temperature.