A simple quasi-2D numerical model of a thermogage furnace

Chahine, K; Ballico, M; Reizes, J; Madadnia, J

A simple quasi-2D numerical model of a thermogage furnace

Chahine, K Ballico, M Reizes, J Madadnia, J

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Publication Type:: Journal Article
Citation:: International Journal of Thermophysics, 2007, 28 (6), pp. 2118 - 2127
Issue Date:: 2007-12-01

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Field	Value	Language
dc.contributor.author	Chahine, K	en_US
dc.contributor.author	Ballico, M	en_US
dc.contributor.author	Reizes, J	en_US
dc.contributor.author	Madadnia, J	en_US
dc.date.issued	2007-12-01	en_US
dc.identifier.citation	International Journal of Thermophysics, 2007, 28 (6), pp. 2118 - 2127	en_US
dc.identifier.issn	0195-928X	en_US
dc.identifier.uri	http://hdl.handle.net/10453/3272
dc.description.abstract	A simple quasi-2D model for the temperature distribution in a graphite tube furnace is presented. The model is used to estimate the temperature gradients in the furnace at temperatures above which contact sensors can be used, and to assist in the redesign of the furnace heater element to improve the temperature gradients. The Thermogage graphite tube furnace is commonly used in many NMIs as a blackbody source for radiation thermometer calibration and as a spectral irradiance standard. Although the design is robust, easy to operate and can change temperature rapidly, it is limited by its effective emissivity of typically 99.5-99.8%. At NMIA, the temperature gradient along the tube is assessed using thermocouples up to about 1,500°C, and the blackbody emissivity is calculated from this. However, at higher operating temperatures (up to 2,900°C), it is impractical to measure the gradient, and we propose to numerically model the temperature distributions used to calculate emissivity. In another paper at this conference, the model is used to design an optimized heater tube with improved temperature gradients. In the model presented here, the 2-D temperature distribution is simplified to separate the axial and radial temperature distributions within the heater tube and the surrounding insulation. Literature data for the temperature dependence of the electrical and thermal conductivities of the graphite tube were coupled to models for the thermal conductivity of the felt insulation, particularly including the effects of allowing for a gas mixture in the insulation. Experimental measurements of the temperature profile up to 1,500°C and radial heat fluxes up to 2,200°C were compared to the theoretical predictions of the model and good agreement was obtained. © 2007 Springer Science+Business Media, LLC.	en_US
dc.relation.ispartof	International Journal of Thermophysics	en_US
dc.relation.isbasedon	10.1007/s10765-007-0281-0	en_US
dc.subject.classification	Chemical Engineering	en_US
dc.title	A simple quasi-2D numerical model of a thermogage furnace	en_US
dc.type	Journal Article
utslib.citation.volume	6	en_US
utslib.citation.volume	28	en_US
utslib.for	0203 Classical Physics	en_US
utslib.for	0306 Physical Chemistry (incl. Structural)	en_US
utslib.for	0904 Chemical Engineering	en_US
dc.location.activity	Alberta, CANADA
pubs.embargo.period	Not known	en_US
pubs.organisational-group	/University of Technology Sydney
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Electrical and Data Engineering
pubs.organisational-group	/University of Technology Sydney/Faculty of Engineering and Information Technology/School of Mechanical and Mechatronic Engineering
utslib.copyright.status	open_access
pubs.issue	6	en_US
pubs.publication-status	Published	en_US
pubs.volume	28	en_US

Abstract:

A simple quasi-2D model for the temperature distribution in a graphite tube furnace is presented. The model is used to estimate the temperature gradients in the furnace at temperatures above which contact sensors can be used, and to assist in the redesign of the furnace heater element to improve the temperature gradients. The Thermogage graphite tube furnace is commonly used in many NMIs as a blackbody source for radiation thermometer calibration and as a spectral irradiance standard. Although the design is robust, easy to operate and can change temperature rapidly, it is limited by its effective emissivity of typically 99.5-99.8%. At NMIA, the temperature gradient along the tube is assessed using thermocouples up to about 1,500°C, and the blackbody emissivity is calculated from this. However, at higher operating temperatures (up to 2,900°C), it is impractical to measure the gradient, and we propose to numerically model the temperature distributions used to calculate emissivity. In another paper at this conference, the model is used to design an optimized heater tube with improved temperature gradients. In the model presented here, the 2-D temperature distribution is simplified to separate the axial and radial temperature distributions within the heater tube and the surrounding insulation. Literature data for the temperature dependence of the electrical and thermal conductivities of the graphite tube were coupled to models for the thermal conductivity of the felt insulation, particularly including the effects of allowing for a gas mixture in the insulation. Experimental measurements of the temperature profile up to 1,500°C and radial heat fluxes up to 2,200°C were compared to the theoretical predictions of the model and good agreement was obtained. © 2007 Springer Science+Business Media, LLC.

Please use this identifier to cite or link to this item:

http://hdl.handle.net/10453/3272