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Experimental and numerical heat transfer investigation in a tubular heat exchanger with delta-wing tape inserts.
- Source :
-
Chemical Engineering & Processing . Nov2016, Vol. 109, p164-177. 14p. - Publication Year :
- 2016
-
Abstract
- Effects of insertion of a straight tape with double-sided delta wing pairs (called “delta-wing tape”, DWT) used as a longitudinal vortex generator (LVG) on forced convective heat transfer and flow friction characteristics in a uniform heat-flux heat exchanger tube are investigated experimentally and numerically in the present work. The experiment is conducted for turbulent airflow with the Reynolds number ( Re ) from 4200 to 25,500. The delta wings are in a forward-wing arrangement with three wing inclination angles (α = 30°, 45° and 60°) and with five ratios of wing-pitch to tube-diameter ( P / D = PR = 0.5, 1.0, 1.5, 2.0 and 2.5). Influences of the DWT insert on heat transfer in terms of Nusselt number (Nu) and pressure drop in the form of friction factor ( f ) are examined. The results indicate that the DWT provides the increases in Nu and f up to 505% and 69 times above the plain tube, respectively and the maximum thermal enhancement factor (TEF) is at 1.49. The 60° DWT with PR = 0.5 yields the highest Nu and f but the 30° one with PR = 1.0 gives the best TEF. To understand the flow structure and heat transfer mechanism, a three dimensional CFD simulation of the inserted tube is also performed. The simulated results are validated and are in good agreement with the current measurements. A simulated heat transfer and fluid flow structure is also reported. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 02552701
- Volume :
- 109
- Database :
- Academic Search Index
- Journal :
- Chemical Engineering & Processing
- Publication Type :
- Academic Journal
- Accession number :
- 118696681
- Full Text :
- https://doi.org/10.1016/j.cep.2016.09.005