Experimental Study on Thermal Conductivity of Orange Juice Using Probe System

Abstract

An improved thermal conductivity probe system consisting of a probe heater, control circuits and data test system was developed and described. It has the merits of the short duration of the experiments, simplicity, high accuracy, and relatively small sample requirement. The measurement time is about 20 s. The effective volume of sample is 50 ml. Calibration of the probe with glycerin and ethanol in this work exhibits an accuracy of 1.4% and 1.9%, respectively. The probe system was used to measure the thermal conductivity of orange juice. The measured thermal conductivity values were linearly dependent on the concentration and temperature of the orange juice. A decrease in the concentration of orange juice and an increase in the temperature resulted in an increase in the values of thermal conductivity. However, the influence of concentration on the thermal conductivity of orange juice was stronger than that of temperature. An empirical model for the thermal conductivity of orange juice as a function of concentration and temperature was obtained.