Research Paper

Microfluidics and Nanofluidics

, Volume 2, Issue 4, pp 291-300

First online:

Spatially resolved temperature measurement in microchannels

  • V.A. PatilAffiliated withDepartment of Mechanical Engineering, Oregon State University
  • , V. NarayananAffiliated withDepartment of Mechanical Engineering, Oregon State University Email author 

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Non-intrusive local temperature measurement in convective microchannel flows using infrared (IR) thermography is presented. This technique can be used to determine local temperatures of the visualized channel wall or liquid temperature near this wall in IR-transparent heat sinks. The technique is demonstrated on water flow through a silicon (Si) microchannel. A high value of a combined liquid emissivity and substrate overall transmittance coupled with a low uncertainty in estimating this factor is important for quantitative temperature measurement using IR thermography. The test section design, and experimental and data analysis procedures that provide increased sensitivity of the detected intensity to the desired temperature are discussed. Experiments are performed on a 13-mm long, 50 μm wide by 135 μm deep Si microchannel at a constant heat input to the heat sink surface for flow rates between 0.6 and 1.2 g min−1. Uncertainty in fluid temperature varies from a minimum of 0.60°C for a Reynolds number (Re) of 297 to a maximum of 1.33°C for a Re of 251.


Microchannels Microscale heat transfer Infrared thermography Spatially resolved Temperature measurement Single-phase flows