Infrared thermography: An optical method in heat transfer and fluid flow visualisation

Astarita, Tommaso; Cardone, Gennaro; Carlomagno, Giovanni Maria

doi:10.1016/j.optlaseng.2005.04.006

Cited by 70 publications

(33 citation statements)

References 20 publications

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“…A detailed analysis of the heat flux sensors that can be used with IR thermography can be found in Carlomagno and de Luca (1989) and Astarita et al (2006).…”

Section: Heat Flux Sensorsmentioning

confidence: 99%

Infrared thermography for convective heat transfer measurements

2010

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This paper deals with the evolution of infrared (IR) thermography into a powerful optical tool that can be used in complex fluid flows to either evaluate wall convective heat fluxes or investigate the surface flow field behavior. Measurement of convective heat fluxes must be performed by means of a thermal sensor, where temperatures have to be measured with proper transducers. By correctly choosing the thermal sensor, IR thermography can be successfully exploited to resolve convective heat flux distributions with both steady and transient techniques. When comparing it to standard transducers, the IR camera appears very valuable because it is non-intrusive, it has a high sensitivity (down to 20 mK), it has a low response time (down to 20 ls), it is fully two dimensional (from 80 k up to 1 M pixels, at 50 Hz) and, therefore, it allows for better evaluation of errors due to tangential conduction within the sensor. This paper analyses the capability of IR thermography to perform convective heat transfer measurements and surface visualizations in complex fluid flows. In particular, it includes the following: the necessary radiation theory background, a review of the main IR camera features, a description of the pertinent heat flux sensors, an analysis of the IR image processing methods and a report on some applications to complex fluid flows, ranging from natural convection to hypersonic regime.

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“…A detailed analysis of the heat flux sensors that can be used with IR thermography can be found in Carlomagno and de Luca (1989) and Astarita et al (2006).…”

Section: Heat Flux Sensorsmentioning

confidence: 99%

Infrared thermography for convective heat transfer measurements

2010

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“…In the second half of the turn, along the front wall it is possible to see a decrease in the convective heat transfer coefficient (L-2, Fig. 5) that was already observed by Astarita et al (2006). Indeed, the two counterrotating vortices, visualized in the first half of the turn, tend to promote the birth of another couple of counter-rotating vortices, known in literature as Dean vortices (y/D = 1.2 and 1.37, Fig.…”

Section: Static Casementioning

confidence: 52%

“…In order to evaluate the convective heat transfer coefficient h, the heated thin foil heat flux sensor (Astarita et al 2006) coupled with the scanning of the surface temperature by an infrared camera has been used. In particular, for each pixel of the digitized thermal image, h is calculated by means of…”

Section: Heat Transfer Measurementsmentioning

confidence: 99%

Thermo-fluid-dynamic analysis of the flow in a rotating channel with a sharp “U” turn

2012

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Infrared thermography has been employed to carry out a detailed convective heat transfer measurements at Re = 20,000 in a two-pass square channel both for the static case (absence of channel rotation) and for the rotating case (Ro = 0.3). At the same time, the main and secondary flow fields have been measured by means of particle image velocimetry with the aim to investigate how the flow behavior affects the local distributions of the convective heat transfer coefficient for the two cases. The normal-towall velocity component (w) and the turbulent kinetic energy, both measured close to the heat exchanging wall, have been used to formulate an empirical heat transfer correlation within an attempt to identify the role performed by these two quantities on the convective heat transfer coefficient distributions. The latter ones have been reported in terms of normalized Nusselt number (Nu/Nu*) maps, where Nu* is the Nusselt number evaluated with the classical Dittus-Bölter correlation.

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“…The relatively high frequency response of the printed circuit board suffices to follow the temporal evolution of the local convective heat transfer coefficient hf , measured by using the heated thin foil sensor [12], i.e. by using the relation: (2) where qj is the Joule heat flux input, qr the radiative heat flux to ambient, Tw is the wall temperature and Taw is the adiabatic wall temperature that coincides with the initial average temperature of the working fluid in the box.…”

Section: Heat Transfer Measurementmentioning

confidence: 99%

An experimental analysis in horizontal convection with IR thermography

Ceglia¹,

Discetti²

2012

Proceedings of the 2012 International Conference on Quantitative InfraRed Thermography

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The aim of this work is to investigate by means of infrared thermography the features of the boundary layer developing on the bottom base of a water-filled volume where a differential heating input is provided. The circulation induced by piecewise thermal conditions on a horizontal boundary is commonly referred as horizontal convection. In the present study, a uniform temperature is imposed on one half of the bottom base of a Plexiglass® box filled with degassed water, while on the other half a uniform heat flux input is provided; on the other box boundaries, the condition of adiabatic wall is reproduced. The range of tested RaL numbers (referred to the heat flux input and box depth) is 5.54x10 9 ÷7.63x10 10 . The transition of the boundary layer and the development of the time evolution of the coherent structures motion are observed on the half base where the uniform heat flux input is provided. At the same location, the onset of longitudinal streamwise rolls and, subsequently, the rise of a strong vertical plume are followed for all the tested operating conditions.

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Infrared thermography: An optical method in heat transfer and fluid flow visualisation

Cited by 70 publications

References 20 publications

Infrared thermography for convective heat transfer measurements

Infrared thermography for convective heat transfer measurements

Thermo-fluid-dynamic analysis of the flow in a rotating channel with a sharp “U” turn

An experimental analysis in horizontal convection with IR thermography

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