Change search
ReferencesLink to record
Permanent link

Direct link
Heat Transfer Augmentation: Radiative-Convective Heat Transfer in a Tube With Fiber Array Inserts
KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.ORCID iD: 0000-0002-3661-7016
2010 (English)In: Journal of heat transfer, ISSN 0022-1481, Vol. 132, no 2Article in journal (Refereed) Published
Abstract [en]

Gas-phase heat transfer plays a critical role in many high temperature applications, such as preheaters, combustors, and other thermal equipment. In such cases common heat transfer augmentation methods rely on the convective component alone to achieve improved internal performance. Radiatively assisted heat transfer augmentation has been suggested as a way to overcome limitations in convective-only enhancement. One example of such a technique is the fiber array insert; thermal radiation emitted by tube walls is captured by a large number of slender fibers, which in turn convect heat to the flowing fluid. Previous numerical studies have indicated that this technique represents a promising enhancement method warranting further investigation. This paper presents results from an experimentally based feasibility study of fiber array inserts for heat transfer augmentation in an externally heated duct. Fibers composed of 140 mu m silicon carbide and 150 mu m stainless steel were assembled in arrays with porosities around 0.98, and were tested for empty-tube Reynolds numbers ranging from 17,500 to 112,500 and wall temperatures from ambient up to 750 degrees C. The arrays cause a significant pressure drop-roughly two orders of magnitude higher than the empty-tube case-but tube-side heat transfer coefficients were improved by up to 100% over the convective-only case in the low flow rate regime. The stainless steel fiber array exhibited similar heat transfer performance as the silicon carbide case, although pressure drop characteristics differed owing to variations in fluid-structure flow phenomena. Pressure drop data were roughly within the range of d'Arcy law predictions for both arrays, and deviations could be explained by inhomogeneities in fiber-to-fiber spacing. Heat transfer was found to depend nonlinearly on wall temperature and flow rate, in contrast to previously reported numerical data.

Place, publisher, year, edition, pages
2010. Vol. 132, no 2
Keyword [en]
convection, porosity, silicon compounds, stainless steel, turbulence, enhancement, flow
National Category
Mechanical Engineering
URN: urn:nbn:se:kth:diva-19037DOI: 10.1115/1.4000189ISI: 000272613600020ScopusID: 2-s2.0-77955283157OAI: diva2:337084
QC 20100525Available from: 2010-08-05 Created: 2010-08-05 Last updated: 2011-01-21Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopus

Search in DiVA

By author/editor
Martin, Andrew R.
By organisation
Heat and Power Technology
In the same journal
Journal of heat transfer
Mechanical Engineering

Search outside of DiVA

GoogleGoogle Scholar
The number of downloads is the sum of all downloads of full texts. It may include eg previous versions that are now no longer available

Altmetric score

Total: 41 hits
ReferencesLink to record
Permanent link

Direct link