Title: Application of Tnfrared Thermography for Temperature Measurement in Microscale Internal and External Flows. Abstract Approved:

Infrared (IR) thermography is applied to estimate heat transfer rates in external and internal microscale convective flows. The technique and analysis are developed in the context of external jet impingement flow and internal single-phase liquid flows. A heated-thin-foil thermography technique is applied to perform surface temperature visualization on a submerged 125-.tm circular microscale jet impingement. Microscale jets flows are associated with low exit Reynolds number (Re) due to the small characteristic length of the nozzle, but correspondingly high exit velocities, and hence, a high subsonic Mach number. Detailed distributions of heated and adiabatic wall temperature, and local and average Nusselt number (Nu) variations are presented for a single 1 25-km diameter air jet impingement for five laminar exit Re in the range of 690 to 1770 at three nozzle-to-surface spacing of 2, 4, and 6 times Redacted for Privacy the nozzle diameter. The corresponding jet exit Mach numbers vary between 0.26 and 0.63. Lateral heat conduction along the impingement surface is significant and warrants inclusion in the calculation of heat transfer coefficient. Results indicate tha