Infrared Thermography- An Optical Method In Heat Transfer And Flow Visualisation.pdf

ARTICLE IN PRESS
Optics and Lasers in Engineering 44 (2006) 261–281
Infrared thermography: An optical method in
heat transfer and fluid flow visualisation
T. AstaritaÃ, G. Cardone, . Carlomagno
Universita` degli studi di Napoli ‘‘Federico II’’, Dipartimento di Energetica Termofluidodinamica Applicata
e Condizionamenti Ambientali, DETEC, hio 80, 80125 Napoli, Italy
Available online 23 May 2005
Abstract
This paper deals with the evolution of infrared thermography into a powerful optical
method to measure wall convective heat fluxes as well as to investigate the surface flow field
behaviour plex geometries. The mon heat-flux sensors, which are normally
used for the measurements of convective heat transfer coefficients, are critically reviewed.
Since the infrared scanning radiometer leads to the detection of numerous surface
temperatures, its use allows taking into account the effects due to tangential conduction
along the sensor; different operating methods together with their implementations are
discussed. Finally, the capability of infrared thermography to deal with plex fluid
flow configurations is analysed.
r 2005 Elsevier Ltd. All rights reserved.
Keywords: Heat-flux sensors; Convective heat transfer; Surface flow visualisation; Infrared thermography
1. Introduction
Usually, measuring convective heat fluxes requires both a sensor (with its
corresponding thermal model) and some temperature measurements. In the ordinary
techniques [1–6], where temperature is measured by thermocouples, resistance
ÃCorresponding author. Tel.: +39 081 768 3389; fax: +39 081 239 0364.
E-mail address: ******@ (T. Astarita).
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262 T. Astarita et al. / Optics and Lasers in Engineering 44 (2006) 261–281
temperature detectors or pyrometers, each transducer yields either the heat flux at a
single point, or the space-averaged on