Civil and Environmental Engineering Publications
A novel thin-film temperature and heat-flux microsensor for heat transfer measurements in microchannels
Document Type
Article
Publication Date
2012
Journal
LAB ON A CHIP
Volume
12
Issue
3
First Page
652
URL with Digital Object Identifier
https://doi.org/10.1039/c2lc20919e
Last Page
658
Abstract
Temperature and heat-flux measurement at the microscale for convective heat-transfer studies requires highly precise, minimally intrusive sensors. For this purpose, a new generic temperature and heat-flux sensor was designed, calibrated and tested. The sensor allows measurement of temperature and heat flux distributions along the direction of flow. It is composed of forty gold thermoresistances, 85 nm thick, deposited on both sides of a borosilicate substrate. Their sensitivities are about 37.8 mu VK-1, close to those of a K-type wire thermocouple. Using a thermoelectrical model, temperature biases due to the Joule effect were calculated using the current crossing each thermoresistance and the heat-transfer coefficient. Finally, heat-transfer measurements were performed with deionized water flowing in a straight PDMS microchannel for various Reynolds numbers. The Nusselt number was obtained for microchannels of 50 to 10 mu m span. The results were found to be in good agreement with classical Nu-Re macroscopic correlations.