Noninvasive temperature measurements of RLIF and nPIT in DI water flow microchannels

Experiments were performed herein to examine the near-wall water flow/thermal characteristics and bulk flow behavior in a 20 mm long microchannel with a height of 45 μm (thermal) and a width of 200 μm, through the noninvasive optical measuring techniques of nPIT and RLIF. The corresponding streamwise wall temperature distribution (45 μm channel) was measured. It was found that at Re = 2, the flow can be fully developed thermally. In addition, both the local heat transfer coefficient and the corresponding Nusselt number were obtained via the RLIF and traditional thermocouple measurements. When compared to the results of previous studies our results are in good agreement.