CFD analysis of mixing and buoyancy effects of a diffuser jet in stratified region of a solar pond

Solar pond is a stratified region capable of storing thermal energy obtained through solar radiations up to 95°C. This energy is extremely useful in various industrial applications ranging from electricity generation and desalination to refrigeration and hot water consumption. The ability of a pond to collect and store thermal energy in storage zone is dependent on effective stratification to suppress natural thermal convection. This stratified region is formed as a result of injection of a solution of varying salinity densities into a saline region. Once formed, maintenance of this stratified region is of utmost importance to trap maximum heat in the pond. This is carried out through injection of saline water through diffuser in specific regions to overcome the effects of dissociation. Diffuser design remained an area of utmost interest in the evolution of solar pond and detailed research has been carried out to overcome the effect of buoyancy in the stratified region and extend the range of plume emanated from the diffuser. Diffusers of varying designs and shapes including diffusers with round and rectangular outlets have been employed in solar ponds over the past few decades. Although researchers have concluded that semi-circular diffusers with rectangular slots are more efficient, yet limited research has been carried out to validate these results using Computational Fluid Dynamics. In research focus has been laid on diffuser designs and comparison of these designs followed by computational analysis of their effect on the emanating flow. Various CFD modeling approaches from the family of Reynolds-Averaged Navier Stokes (RANS) have been discussed in this research including the semi empirical k-E model based upon the dissipation rate and turbulent kinetic energy. Based upon these results optimum diffuser design for stratification in a salinity gradient solar pond has been established using CFD technique which has previously been studied on a limited scale. This has enabled in design of optimized gradient formation and maintenance mechanism.