Effects of Concentration on Free Convective Heat Transfer in Glycerol

Abstract

In a gravitational field, density differences can drive fluid motion in a process knownas freeconvection. Free convection and changing concentration of glycerol are related throughtheconcept of density-driven flow. The effects of concentration on free convective heat transfer isstudied for glycerol for the range of Rayleigh numbers 10 ^-6 ≤ Ra ≤ 10⁹ and Prandtl numbers 6.66≤Pr ≤ 11630. Various  appropriate correlations due to Churchill and Chu, Raithby and Holland, Kuehn and Goldstein, Fand et al and Jaluria are used to evaluate  the free convective Nusselt number in glycerol as a function of Rayleigh number with fixed concentrations of 0%, 20%, 40%, 60%, 80% and  100%. Additionally, the Rayleigh number is kept fixed at three regimes of 10^-6 , 100and 10⁹ and the free Nusselt number is  evaluated as a function of concentration of glycerol. Amaximum of 42% increase in Nusselt number with concentration is observed  fromthe Fandet al correlation