Physicothermal Properties of Aqueous Sodium Chloride Solutions

Abstract

Physicothermal properties of sodium chloride solutions as complementary information to the existent in literature were experimentally measured under different conditions of mass concentration (in the range of 0.040 kg NaCl/kg solution to 0.240 kg NaCl/kg solution) and temperature (between 4 and 52 °C). Density, dynamic viscosity, specific heat capacity and thermal conductivity were measured using a standard volumetric glass pycnometer, rheometer, differential scanning calorimeter and coaxial dual‐cylinder apparatus, respectively. Prandtl number was calculated with the measured properties. Statistical analyses were carried out to determine the effect of the salt concentration and temperature on the properties, and, subsequently, different correlations were proposed to estimate the experimental results with acceptable goodness of fit. Linear relationships were observed among tested properties and sodium chloride concentrations, whereas the temperature dependence was specific for each property.

Experimental data about binary solutions, such as sodium chloride solutions, are insufficient, and much specific information is still unknown. The knowledge of this information is necessary in the effective designing of food processing equipment such as evaporators, pumps, heat exchangers, filters and mixers, as well as in the food process control. Additionally, the calculation of Prandtl number from experimental data plays an important role for understanding the physical mechanism of the fluid flow and heat transfer.