Local heat transfer measurements on a curved microsurface using liquid crystal thermography

R. Muwanga, Ibrahim Hassan

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

In this paper, local heat transfer measurements in circular mini- and microchannels are presented through the use of unencapsulated thermochromic liquid crystals for local wall temperature measurement Microchannel heat transfer is fundamental to the design of a number of novel technologies in development for thermal control. Measurements are carried out in three different stainless steel tubes with nominal inner diameters of 1.07,0.51, and 0.25 mm. The working fluids are distilled water and FC-72. A unique localized calibration of the thermochromic liquid crystal material is employed to minimize the effects of lighting nonuniformity and the effect of variable coating thickness. Local heat transfer and frictional pressure drop measurements are presented for the laminar, transitional, and turbulent flow regimes. The results are compared with correlations for both macro- and microchannels in the turbulent regime and show that, considering experimental uncertainty, both correlations are adequate for the experimental range investigated. Overall, the methods developed in this work demonstrate that the unencapsulated forms of thermochromic liquid crystals are a viable approach for temperature measurement in microheat transfer experiments.

Original languageEnglish
Pages (from-to)884-894
Number of pages11
JournalJournal of Thermophysics and Heat Transfer
Volume20
Issue number4
DOIs
Publication statusPublished - Oct 2006
Externally publishedYes

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microchannels
heat transfer
liquid crystals
temperature measurement
working fluids
wall temperature
pressure drop
laminar flow
nonuniformity
turbulent flow
illuminating
stainless steels
tubes
coatings
water

ASJC Scopus subject areas

  • Condensed Matter Physics

Cite this

Local heat transfer measurements on a curved microsurface using liquid crystal thermography. / Muwanga, R.; Hassan, Ibrahim.

In: Journal of Thermophysics and Heat Transfer, Vol. 20, No. 4, 10.2006, p. 884-894.

Research output: Contribution to journalArticle

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