The Development of a Microfabricated Transient Planar Source (TPS) Sensor for Measuring Thermal Conductivity of Nanofluids

Abstract

A re-design of the sensor for measuring thermal conductivity of nanofluids is developed. The Transient Planar Source (TPS) method is used to measure the thermal conductivity of a nanofluid. This TPS sensing element consists of a heat source and a temperature sensor, where the temperature coefficient of resistance is derived from a calibration of the sensor, in a measurement of the resistance across the leads of the sensor. The TPS system (Hot Disk) consists of a 10-mm-diameter sensor head fixed into a nanofluid measurement chamber, This sensor is used to measure the thermal conductivity of Cu-H2O nanofluids with the effect of pH surfactant included. These nanofluids were prepared by a two-step method, which results in an average 100-nm particle size distribution. To improve the dispersion behavior, a surfactant at pH 9.2 is also used. The method shows good utility for measuring a thermal conductivity at a wide range of temperatures.

Keywords: Nanofluids, TPS, Thermal conductivity, Sensor