Study of boundaries equilibrium in a shallow solar pond

Abstract

Abstract. One-dimensional mass and heat transfer models have been provided to find salinity and temperature gradients in a gradient layer of a solar pond. Using finite difference method (FDM), heat and mass transfer differential equations were discretized by Crank - Nicolson scheme. The present study is based on the experimental data of a solar pond in Ferdowsi University of Mashhad, obtained in a period of 126 days from May to September 1999. Increase in concentration and temperature gradient, cause increase and decrease in stability, respectively. Time variations of concentration and temperature gradients are affect the dynamic stability and equilibrium of upper and lower boundaries of the solar pond. The equilibrium of the upper and lower boundaries has been compared using Neilson equilibrium boundary criterion. The numerical data of the lower boundary were far from dynamic instability. Those data had good agreement with the Neilson equilibrium boundary criterion. The dynamic stability of the upper boundary was maintained with time, but the numerical data of the upper boundary were not in keeping with the Neilson equilibrium boundary criterion. Therefore the lower boundary has with time, behaved with more equilibrium towards the upper boundary.