Abstract
Hydrodynamic and thermal characteristics of the fully developed laminar flow and heat transfer in an arbitrarily shaped triangular duct are evaluated using a finite difference technique. The hydrodynamic information encompasses the friction factor, the length from the tube entrance necessary for complete hydrodynamic development, and the incremental pressure drop due to flow development in the entrance section. The Nusselt numbers in the case of an allover isothermal ductNu T , as well as for a duct heated by an axial uniform heat flux while its transverse local periphery is at a constant temperatureNu H , are presented. Comparison of the isosceles results with those from the work of Shah [1], Sparrow and Haji-Sheikh [2], and Schmidt and Newell [3] revealed a maximum difference of about −0.2% in theNu Hi data, less than ±0.5% in theNu T ,about +0.3% in the friction factor, a −0.47% in the incremental pressure drop, and around −1% in the developing entrance length. The deviations from the results of other authors become smaller as the triangular geometry approaches the equilateral.
Zusammenfassung
Mittels einer finiten Differenzenmethode wurde das hydrodynamische und thermische Verhalten einer vollständig ausgebildeten laminaren Strömung und der Wärmeübergang in einem willkürlich geformten dreieckigen Kanal untersucht. Hydrodynamische Erkenntnisse wurden über den Reibungskoeffizienten, die Einlauflänge bis zur vollständig ausgebildeten Strömung und den differentiellen Druckverlust im Einlaufgebiet gewonnen. Weiterhin wird sowohl die Nusselt-Zahl eines überall isothermen Kanals vorgestellt (Nu T ), als auch die im Falle konstanter HeizflächenbelastungNu Hi Ein Vergleich der eigenen Ergebnisse mit denen von Shah [1], Sparrow und Haji-Sheikh [2] sowie Schmidt und Newell [3] zeigt eine maximale Abweichung bei den Werten vonNu Hi von ungefähr −0,2%, weniger als ±0,5% fürNu T , ungefähr +0,3% beim Reibungskoeffizient, −0,47% beim differentiellen Druckverlust und etwa −1% bei der hydraulischen Einströmlänge. Die Abweichungen der Ergebnisse von anderen Autoren werden kleiner, wenn sich die Dreiecksgeometrie der Rechtecksgeometrie annähert.
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Abbreviations
- D h :
-
Equivalent Diameter=4A/p
- f :
-
Friction Factor
- K ∞ :
-
Incremental Pressure Drop
- L e :
-
Entrance Length
- Nu Hi :
-
Nusselt Number — Constant Axial Heat Flux, Isothermal Local Periphery
- Nu T :
-
Nusselt Number — Isothermal Duct
- Re :
-
Reynolds Number
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Abdel-Wahed, R.M., Attia, A.E. Fully developed laminar flow and heat transfer in an arbitrarily shaped triangular duct. Warme- und Stoffübertragung 18, 83–88 (1984). https://doi.org/10.1007/BF01006603
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DOI: https://doi.org/10.1007/BF01006603