Study on designing measurement system of thermal conductivity based on one-dimensional steady-state method

Abstract

Thermal conductivity has wide application in various fields such as in agricultural and food sectors. In a food industry, measuring the thermal conductivity is designed to optimize the thermal process such as drying, sterilization, and freezing. In this study, a system to measure thermal conductivity is designed according to one-dimensional steady state method through Fourier formula. The experiment uses samples consisting of rice-based product (rice grain, rice powder, rice flour, cooked rice) and whole milk powder. The analysis will be performed in the range of 15-30 minutes on its steady condition. The results are verified with the literature data and evaluated through degree equivalence calculation. As a result, the system can distinguish the samples which has different texture and composition. Furthermore, the system can figure the increasing trend of thermal conductivity with the raise of moisture content. However, in most case, thermal conductivities of the measured samples have higher value compared to the literature data (2-4 times higher). The disparity due to the variation of heating temperature, sample condition, measurement technique, and analysis. Several finding to gain more reliable system can be done by improving the insulation or evaluating the mathematical calculation into a two-dimension approximation. In general, the design of the system is plausible for measuring the thermal conductivity.