Theoretical analysis of novel device for measuring the thermal conductivity of liquids

This paper aims to propose a novel design of microdevice for measuring the thermal conductivity of a liquid drop with a few volumes. The microdevice consists of a thin film that covers a cavity of the substrate. The thin film has a circular centered heater and several temperature sensors that are located at different radial locations from the heater. Once a known voltage is applied to the heater, the thermal conductivity of liquid drop that spreads over the heater and the temperature sensors can be determined from the measured temperature responses at different radial locations. This study provides theoretical predictions of temperature responses that are obtained from the diffusion equation of a semi-infinite cylindrical model. With an uncertainty in temperature measurement of 0.1 K, the uncertainty in determining the nominal thermal conductivity of 0.3 W/m-K is less than 0.3%.