Asymmetrical non-uniform heat flux distributions for laminar flow heat transfer with mixed convection in a horizontal circular tube

Show simple item record Okafor, Izuchukwu F. Dirker, Jaco Meyer, Josua P. 2018-02-06T04:46:09Z 2019
dc.description.abstract Non-symmetric heat flux distributions in terms of gravity in solar collector tubes influence buoyancy-driven secondary flow which has an impact on the associated heat transfer and pressure drop performance. In this study the influence of the asymmetry angle (0°, 20°, 30° and 40°) with regard to gravity for non-uniform heat flux boundaries in a horizontal circular tube was investigated numerically. A stainless steel tube with an inner diameter of 62.68 mm, a wall thickness of 5.16 mm, and a length of 10 m was considered for water inlet temperatures ranging from 290 K to 360 K and inlet Reynolds numbers ranging from 130 to 2000. Conjugate heat transfer was modelled for different sinusoidal type outer surface heat flux distributions with a base-level incident heat flux intensity of 7.1 kW/m2. It was found that average internal heat transfer coefficients increased with the circumferential span of the heat flux distribution. Average internal and axial local heat transfer coefficients and overall friction factors were at their highest for symmetrical heat flux cases (gravity at 0º) and lower for asymmetric cases. The internal heat transfer coefficients also increased with the inlet fluid temperature and decreased with an increase in the external heat loss transfer coefficient. Friction factors decreased with an increase in fluid inlet temperature or an increase in the external heat loss transfer coefficients of the tube model. en_ZA
dc.description.department Mechanical and Aeronautical Engineering en_ZA
dc.description.embargo 2019-01-16
dc.description.librarian hj2018 en_ZA
dc.description.uri en_ZA
dc.identifier.citation Izuchukwu F. Okafor, Jaco Dirker & Josua P. Meyer (2019) AsymmetricalNon-Uniform Heat Flux Distributions For Laminar Flow Heat Transfer With MixedConvection In a Horizontal Circular Tube, Heat Transfer Engineering, 40:1-2, 109-127, DOI:10.1080/01457632.2017.1421055. en_ZA
dc.identifier.issn 0145-7632 (print)
dc.identifier.issn 1521-0537 (online)
dc.identifier.other 10.1080/01457632.2017.1421055
dc.language.iso en en_ZA
dc.publisher Taylor and Francis en_ZA
dc.rights © 2018 Taylor & Francis Group, LLC. This is an electronic version of an article published in Heat Transfer Engineering, vol. 40, no. 1-2, pp. 109-127, 2019, doi : 10.1080/01457632.2017.1421055. Heat Transfer Engineering is available online at : http://www.tandfonline.comloi/uhte20. en_ZA
dc.subject Heat flux en_ZA
dc.subject Transfer coefficient en_ZA
dc.subject Non-uniform heat fluxes en_ZA
dc.subject Local heat transfer coefficient en_ZA
dc.subject Heat flux distributions en_ZA
dc.subject Fluid inlet temperature en_ZA
dc.subject Conjugate heat transfer en_ZA
dc.subject Tubular steel structures en_ZA
dc.subject Tubes (components) en_ZA
dc.subject Stainless steel en_ZA
dc.subject Reynolds number en_ZA
dc.subject Laminar flow en_ZA
dc.subject Heat transfer coefficients en_ZA
dc.subject Heat transfer en_ZA
dc.subject Heat losses en_ZA
dc.subject Friction en_ZA
dc.subject Pressure drop en_ZA
dc.subject Internal heat transfer en_ZA
dc.title Asymmetrical non-uniform heat flux distributions for laminar flow heat transfer with mixed convection in a horizontal circular tube en_ZA
dc.type Postprint Article en_ZA

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