Local heat transfer measurements in micro geometries using liquid crystal thermography

Roland S. Muwanga, Ibrahim Hassan

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

A technique is described on the use of un-encapsulated thermochromic liquid crystals (TLC's) to measure the local heat transfer coefficient in microchannel geometries. Microchannel heat transfer is at the heart of the microchannel heat sink, a recent technology aimed at managing the stringent thermal requirements of today's high-end electronics. The microencapsulated form of liquid crystals are well established for use in surface temperature mapping. Limited studies however are available on the use of the un-encapsulated form. This form is advantageous as it offers the potential for high spatial resolution which is necessary for micro geometries. The evaluation of this method and its associated difficulties is therefore the motivation for the experimental facility developed and described in the present work. Measurements are made in a closed loop facility combined with a microscopic imaging system and automated data acquisition. Results are presented for a circular tube made of stainless steel with an inner diameter of 1.0668mm. A localized TLC calibration is used to account for non-uniformities in the coating and variation of lighting conditions. Results for single-phase, thermally developing, laminar and turbulent flows using distilled water are presented. The results show that the correlations for conventional size channels are adequate for predicting the heat transfer characteristics of a nominally sized 1mm channel.

Original languageEnglish
Title of host publicationProceedings of the 3rd International Conference on Microchannels and Minichannels, 2005
Pages217-224
Number of pages8
VolumePART A
Publication statusPublished - 2005
Externally publishedYes
Event3rd International Conference on Microchannels and Minichannels, ICMM2005 - Toronto, ON, Canada
Duration: 13 Jun 200515 Jun 2005

Other

Other3rd International Conference on Microchannels and Minichannels, ICMM2005
CountryCanada
CityToronto, ON
Period13/6/0515/6/05

Fingerprint

Microchannels
Liquid crystals
Heat transfer
Geometry
Heat sinks
Laminar flow
Imaging systems
Heat transfer coefficients
Turbulent flow
Data acquisition
Electronic equipment
Stainless steel
Lighting
Calibration
Coatings
Water
Temperature

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Muwanga, R. S., & Hassan, I. (2005). Local heat transfer measurements in micro geometries using liquid crystal thermography. In Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005 (Vol. PART A, pp. 217-224). [ICMM2005-75019]

Local heat transfer measurements in micro geometries using liquid crystal thermography. / Muwanga, Roland S.; Hassan, Ibrahim.

Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005. Vol. PART A 2005. p. 217-224 ICMM2005-75019.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Muwanga, RS & Hassan, I 2005, Local heat transfer measurements in micro geometries using liquid crystal thermography. in Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005. vol. PART A, ICMM2005-75019, pp. 217-224, 3rd International Conference on Microchannels and Minichannels, ICMM2005, Toronto, ON, Canada, 13/6/05.
Muwanga RS, Hassan I. Local heat transfer measurements in micro geometries using liquid crystal thermography. In Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005. Vol. PART A. 2005. p. 217-224. ICMM2005-75019
Muwanga, Roland S. ; Hassan, Ibrahim. / Local heat transfer measurements in micro geometries using liquid crystal thermography. Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005. Vol. PART A 2005. pp. 217-224
@inproceedings{46bf27a608a74ded8bbfc0b913c0f5fb,
title = "Local heat transfer measurements in micro geometries using liquid crystal thermography",
abstract = "A technique is described on the use of un-encapsulated thermochromic liquid crystals (TLC's) to measure the local heat transfer coefficient in microchannel geometries. Microchannel heat transfer is at the heart of the microchannel heat sink, a recent technology aimed at managing the stringent thermal requirements of today's high-end electronics. The microencapsulated form of liquid crystals are well established for use in surface temperature mapping. Limited studies however are available on the use of the un-encapsulated form. This form is advantageous as it offers the potential for high spatial resolution which is necessary for micro geometries. The evaluation of this method and its associated difficulties is therefore the motivation for the experimental facility developed and described in the present work. Measurements are made in a closed loop facility combined with a microscopic imaging system and automated data acquisition. Results are presented for a circular tube made of stainless steel with an inner diameter of 1.0668mm. A localized TLC calibration is used to account for non-uniformities in the coating and variation of lighting conditions. Results for single-phase, thermally developing, laminar and turbulent flows using distilled water are presented. The results show that the correlations for conventional size channels are adequate for predicting the heat transfer characteristics of a nominally sized 1mm channel.",
author = "Muwanga, {Roland S.} and Ibrahim Hassan",
year = "2005",
language = "English",
isbn = "0791841855",
volume = "PART A",
pages = "217--224",
booktitle = "Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005",

}

TY - GEN

T1 - Local heat transfer measurements in micro geometries using liquid crystal thermography

AU - Muwanga, Roland S.

AU - Hassan, Ibrahim

PY - 2005

Y1 - 2005

N2 - A technique is described on the use of un-encapsulated thermochromic liquid crystals (TLC's) to measure the local heat transfer coefficient in microchannel geometries. Microchannel heat transfer is at the heart of the microchannel heat sink, a recent technology aimed at managing the stringent thermal requirements of today's high-end electronics. The microencapsulated form of liquid crystals are well established for use in surface temperature mapping. Limited studies however are available on the use of the un-encapsulated form. This form is advantageous as it offers the potential for high spatial resolution which is necessary for micro geometries. The evaluation of this method and its associated difficulties is therefore the motivation for the experimental facility developed and described in the present work. Measurements are made in a closed loop facility combined with a microscopic imaging system and automated data acquisition. Results are presented for a circular tube made of stainless steel with an inner diameter of 1.0668mm. A localized TLC calibration is used to account for non-uniformities in the coating and variation of lighting conditions. Results for single-phase, thermally developing, laminar and turbulent flows using distilled water are presented. The results show that the correlations for conventional size channels are adequate for predicting the heat transfer characteristics of a nominally sized 1mm channel.

AB - A technique is described on the use of un-encapsulated thermochromic liquid crystals (TLC's) to measure the local heat transfer coefficient in microchannel geometries. Microchannel heat transfer is at the heart of the microchannel heat sink, a recent technology aimed at managing the stringent thermal requirements of today's high-end electronics. The microencapsulated form of liquid crystals are well established for use in surface temperature mapping. Limited studies however are available on the use of the un-encapsulated form. This form is advantageous as it offers the potential for high spatial resolution which is necessary for micro geometries. The evaluation of this method and its associated difficulties is therefore the motivation for the experimental facility developed and described in the present work. Measurements are made in a closed loop facility combined with a microscopic imaging system and automated data acquisition. Results are presented for a circular tube made of stainless steel with an inner diameter of 1.0668mm. A localized TLC calibration is used to account for non-uniformities in the coating and variation of lighting conditions. Results for single-phase, thermally developing, laminar and turbulent flows using distilled water are presented. The results show that the correlations for conventional size channels are adequate for predicting the heat transfer characteristics of a nominally sized 1mm channel.

UR - http://www.scopus.com/inward/record.url?scp=27744575949&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=27744575949&partnerID=8YFLogxK

M3 - Conference contribution

SN - 0791841855

VL - PART A

SP - 217

EP - 224

BT - Proceedings of the 3rd International Conference on Microchannels and Minichannels, 2005

ER -