Heat transfer analysis of micromachined thermal conductivity sensors

Due to unique features, micromachined thermal sensors are an interesting alternative to classical macroscopic apparatuses for the determination of thermal conductivities. A typical drawback of sophisticated miniaturized sensing elements is the fact that for most devices no analytical solution of the heat conduction equation can be obtained and thus a numerical model has to be implemented to determine the thermal parameter(s) of interest. In this contribution, an analytical model of a micromachined sensor for measuring the thermal conductivity and diffusivity of different liquids is presented. The model not only accounts for the unique sensor geometry but also for additional spurious effects associated with the devices membrane