Using Infrared Thermography to Study Thermal Development in the Entrance Region of a Rectangular Microchannel

Microchannel heat sink with its high heat transfer area density and potentially high heat transfer coefficient has been proposed for applications with high heat fluxes. The objective of this study is to investigate single-phase convection in the thermally developing region of a rectangular microchannel. An infrared thermography provides an effective approach for nonintrusive and spatio-temporal measurement of temperature. The entrance region, where the heat transfer coefficient is higher than that of the fully developed region, is of particular interest for microchannel cooling applications. The present study establishes an innovative benchmark experimental measurement uaing an infrared thermography. The experiments are conducted on a rectangular cross-section microchannel made of aluminum alloy 6061 with dimensions 22mm×1.5mm×0.3mm and covered on the top with a 5mm thick infrared transmitting germanium glass window. Consequently, the temperature distribution in the channel can be observed via the window directly. In order to measure the temperature correctly, all of the aluminum channel surface substrate was anodized such that emissivity can be increased to 0.95. The results show that the temperature distribution can be measured correctly using infrared thermography. And local heat transfer coefficient can be acquired successfully.