Design and development of a test method for the measurement of thermo-physical properties of different materials

Abstract

The guarded hot plate method is widely used to measure the thermal conductivity and thermal resistance of materials having low thermal conductivity. An experimental set-up was designed and fabricated in-house to measure these properties. The set-up was built in accordance with ASTM D5470 standards. A novel insulating material waste tire rubber/polypropylene has been developed from the solid blend of waste tire rubber powder (425–300 µm) mixed with virgin polypropylene granules in a 2.5:1 ratio. The thermal conductivity of the newly developed insulating material in cylindrical solid form has been estimated. Further, thermal conductivity of a conducting material i.e., H-13 tool steel has been found out by using the present experimental set-up. In addition, the thermal contact conductance of a well-known thermal paste i.e., silicon grease has also been estimated for a range of temperatures and pressure using the present set-up. In the present study, the procedure for measuring thermal conductivity has been demonstrated along with the strengths and weaknesses of the experimental set-up and the suitability of the method for different materials. The experimental results reveal that the test method is equally suitable for the analysis of thermal interface material, and for measuring the thermal conductivity of solid specimens giving reliable results.