Experimentation and modeling of convective heat transfer coefficient for evaporation of liquid foods in a pilot plant double effect

Abstract

Abstract Even though the evaporation is a common process in the food industry, there is scarce information about the convective coefficient evaluation as an important parameter for equipment and process design. A research on evaporation of sugar solution in a double effect was carried out. The experimental results obtained in this equipment, from the heat transfer and concentration processes are presented, a range of 2658–6091 W of heat flow was quantified implying computed values of 1431–3763 W/m2K for the convective coefficients and 1020–1815 W/m2K for the overall coefficient. The quantification of the convective coefficient, the fitting methodology and modeling were developed in order, to obtain the correspondent correlations. Then, from a set of several equations, two general relationships are proposed. Both correlations were applied to experimental and supposed data, finding a difference lower than 30% between the experimental and predicted values of the Nusselt number, that was considered as satisfactory.