Numerical investigation of thermal and flow characteristics in a novel converging cone-frustum porous solar receiver, part A: CFD analysis

• Novel converging cone-frustum volumetric receiver is developed for CST plants. • Constructal design optimizes receiver geometry for higher heat transfer efficiency. • Conical shape improves fluid outlet temperature and porous area utilization. • Optimized geometry achieves high thermal efficiency with minimal pressure drop. A solar harvesting system with a porous volumetric receiver offers encouraging results for a better and sustainable energy solution when looking for an alternate source of clean and renewable energy. The present study focuses on the hydrodynamic behavior, effective size, and thermal performance of porous structures utilized as solar volumetric receivers. The evaluation of these essential parameters is performed numerically utilizing the k-ε/Standard turbulence model and the discrete ordinates (DO) radiation model, which is completely integrated with conduction and convection heat transfer. The temperature distributions for both fluid and solid phases are calculated using the Local Thermal Non-Equilibrium Model with volume-averaged governing equations. Effect of input condition on heat removal is also included in this analysis. A novel converging cone frustum shape for the volumetric receiver is developed to optimize its design performance. Different configurations of porous cone frustum-shaped channels are examined, and a comparison is conducted among these configurations by altering design factors such as the cone angle of the frustum, the ratio of inlet diameter to outlet diameter, and heat recovery rate (mass-flow rate). A notable thermal improvement is evident when compared to the prior volumetric receiver under identical volume and intake conditions. Significant enhancement in exit temperature and effective size is attained for the proposed configurations compared to the previously examined design, while maintaining almost same pressure loss.