Abstract
A finite element approach is used to investigate the two-dimensional performance of convecting-radiating fins of rectangular, trapezoidal, triangular, and concave parabolic shapes. The heat transfer rate depends on fin size parameter α, Biot numberBi, radiation-conduction parameterN r , and environment temperatures θ∞ and θ r . Numerical results for the heat transfer rate and the error due to one-dimensional assumption are presented and discussed for each geometry. The highest heat dissipation is achieved with the concave parabolic shape and the lowest with the rectangular shape with the trapezoidal and triangular shapes falling in between. The maximum error of +144 percent is noted for a short and thick rectangular fin (α=1) and −47 percent for a long thin triangular fin (α=20).
Zusammenfassung
Mit Hilfe der Methode der Finiten Elemente wird das zweidimensionale Übertragungsverhalten bezüglich Konvektion und Strahlung von Rippen mit rechteckigem, trapezförmigem, dreieckförmigem und konkav-parabolischem Querschnitt untersucht. Der übertragbare Wärmestrom hängt von dem Rippenparameter 2L/W, der BiotzahlBi, dem StrahlungskonvektionsparameterN r und von den Umgebungstemperaturen θ W und θ r ab. Für jede Geometrieform werden der übertragene Wärmestrom und der bei eindimensionaler Behandlung auftretende Fehler angegeben und diskutiert. Der höchste Wärmeübergang wird mit dem Parabelprofil, der niedrigste mit dem Rechteckprofil erzielt. Trapez- und Dreiecksform liegen dazwischen. Für eine kurze und dicke Rechtecksrippe (2L/W=1) erhält man einen Maximalfehler von +144% und für eine lange dünne Dreiecksrippe (2L/W=20) von −47%.
Similar content being viewed by others
Abbreviations
- Bi :
-
=h w/2k, Biot number
- F :
-
load vector
- h :
-
convective heat transfer coefficient
- J :
-
Jacobian
- k :
-
thermal conductivity of fin
- L :
-
fin length
- m :
-
iteration number
- N :
-
set of basis functions
- N r :
-
=ε σ w T 3 b /2k, radiation-conduction parameter
- q :
-
heat transfer rate per unit fin depth
- Q :
-
=q/k T b , dimensionless heat transfer rate
- T :
-
temperature
- w :
-
fin base thickness
- x :
-
axial coordinate
- X :
-
=α x/L
- y :
-
transverse coordinate
- Y :
-
=y/(w/2)
- α :
-
=L/(w/2)
- ε :
-
emissivity of fin surface
- θ :
-
=T/T b , dimensionless temperature
- σ :
-
Stefan-Boltzmann constant
- Ω :
-
domain of fin
- Γ :
-
perimeter of fin
- 1:
-
one-dimensional conduction
- 2:
-
two-dimensional conduction
- ∞:
-
convective environment
- b :
-
fin base
- r :
-
radiative environment
References
Kraus, A. D.: Sixty-five years of extended surface technology. Appl. Mech. Rev. 41 (1988) 321–364
Irey, R. K.: Errors in the one-dimensional fin solution. Trans. ASME J. Heat Transfer 90 (1968) 175–176
Levitsky, M. J.: The criterion for validity of the fin approximation. Int. J. Heat Mass Transfer 15 (1972) 1960–1963
Lau, W.; Tan, C. W.: Errors in one-dimensional heat transfer analysis in straight and annular fins. Trans. ASME J. Heat Transfer 95 (1973) 549–551
Sfeir, A. A.: The heat balance integral in steady-state conduction. Trans. ASME J. Heat Transfer 98 (1976) 466–470
Suryanarayana, N. V.: Two-dimensional effects on heat transfer rates from an array of straight fins. Trans. ASME J. Heat Transfer 99 (1977) 129–132
Burmeister, L. C.: Triangular fin performance by the heat balance integral method. Trans. ASME J. Heat Transfer 101 (1979) 562–564
Heggs, P. J.; Stone, P. R.: The effects of dimensions on the heat flowrate through extended surfaces. Trans. ASME J. Heat Transfer 102 (1980) 180–182
Look, D. C., Jr.: Two-dimensional fin with non-constant root temperature. Int. J. Heat Mass Transfer 32 (1989) 977–980
Aparecido, J. B.; Cotta, R. M.: Improved one-dimensional fin solutions. Heat Transfer Engineering 11 (1990) 49–59
Aziz, A.; Nguyen, H.: Two-dimensional effects in a triangular convecting fin. J. thermophysics and heat transfer 6, No. 1 (1992) pp. 165–167
Manzoor, M.; Ingham, D. B.; Heggs, P. J.: Improved formulations for the analysis of convecting and radiating finned surfaces. AIAA J. 21 (1983) 120–126
Nguyen, H.; Aziz, A.: Heat transfer from convecting-radiating fins of different profile shapes. Wärme-Stoffübertrag. 27, No. 1 (1992) 67–72
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Aziz, A., Nguyen, H. Two-dimensional performance of convecting-radiating fins of different profile shapes. Wärme - und Stoffübertragung 28, 481–487 (1993). https://doi.org/10.1007/BF01539679
Received:
Issue Date:
DOI: https://doi.org/10.1007/BF01539679