title: A novel thin-film temperature and heat-flux microsensor for heat transfer measurements in microchannels.
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 μV K(-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 μm span. The results were found to be in good agreement with classical Nu-Re macroscopic correlations.
authors.affiliation: Laboratoire de Thermocinétique, UMR CNRS 6607, Ecole Polytechnique, Nantes University, BP 50609, 44306 Nantes, France.
authors.forename: David
authors.initials: D
authors.lastname: Hamadi
authors.forename: Bertrand
authors.initials: B
authors.lastname: Garnier
authors.forename: Herve
authors.initials: H
authors.lastname: Willaime
authors.forename: Fabrice
authors.initials: F
authors.lastname: Monti
authors.forename: Hassan
authors.initials: H
authors.lastname: Peerhossaini