Performance analysis and optimization of elliptic fins circumscribing a circular tube

In the present study, performance of a tube row with annular elliptical fin was compared to the circular type. It was shown that heat transfer coefficient and pressure drop are functions of ratio of horizontal diameter to vertical diameter. It means that not only the diameter ratio, but also ellipse orientation affects heat transfer and pressure drop. Interestingly, it was found out that the pressure drop may be as low as one half of a circular fin tube. Moreover, with the same incoming air velocity, heat transfer coefficient on vertical fin is higher than circular type. Because of the lower pressure drop, higher incoming velocity may be applied, and therefore, higher heat transfer can be achieved. Altogether, tube with annular elliptical fin may be a good candidate for circular type when there is space restriction or severe limitation on pressure drop.

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“…m = 2h k f t f (11) in which k f and t f are fin thermal conductivity and fin thickness, respectively, and d is tube outside diameter and also:…”

Section: Case Study and Data Reductionmentioning

confidence: 99%

“…Kundu and Das [11] proposed a semi-analytical method similar to sector method to approximate elliptical fin efficiency. However, this method ends to a tedious series of Bessel function families.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Flow Over Annular Elliptical Finned Tube Heat Exchangers

Nemati

Samivand

2016

Arab J Sci Eng

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“…(1). Kundu and Das [10] proposed to divided the fin boundary to finite number of segments and approximate each segment as a circular arc to satisfy Eq. (2d) for each segment.…”

Section: Formulation Of the Problemmentioning

confidence: 99%

“…Kunduand Das [10] proposed a semianalytical method similar to sector method to approximate elliptical fin efficiency. However, this method ends to a tedious series of Bessel function families.…”

Section: Introductionmentioning

confidence: 99%

Simple Correlation to Evaluate Efficiency of Annular Elliptical Fin Circumscribing Circular Tube

Nemati

Samivand

2014

Arab J Sci Eng

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Efficiency of annular elliptical fin has been studied numerically. Results show that constant temperature lines do not remain circular in lower aspect ratio fins. So, it is expected that some common methods such as equivalent fin area or sector method do not have enough accuracy. For this reason, at first, a new simple correlation has been proposed to approximate annular circular fin efficiency based on longitudinal fin efficiency and then, comparing to the numerical results, it has been shown that the proposed formula is still applicable if one uses arithmetic mean of elliptical fin lengths and geometric mean of elliptical fin radiuses. List of symbols hConvection heat transfer coefficient (W/m 2 K) I n First kind modified Bessel function of order n k Fin thermal conductivity (W/mK) K n Second kind modified Bessel function of order n L Fin length, r f − r b (m) L Arithmetic mean of major and minor fin lengths,Major and minor fin lengths, (r 2 − r b ) (m) m Thermo-geometry parameters, h kt (m −1 ) N Normal vector r Radial distance from tube center (m) r 1Fin major radios (m) r 2 Fin minor radius (m) r bTube radius (m) r f Circular fin radius (m) R f Normalized fin radius,r f /r b R f 1 Major normalized radiuses, r 1 /r b R f 2 Minor normalized radiuses, r 2 /r b R f

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“…The optimum procedure for a thermally asymmetric convective and radiating annular fin is presented [9]. Kundu and Das [10] develop a comprehensive scheme for optimization of elliptic fins.…”

Section: Introductionmentioning

confidence: 99%

Optimization of a rectangular profile annular fin based on fixed fin height

Kang

2009

J Mech Sci Technol

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The optimum performance and fin length of a rectangular profile annular fin are presented using a variations separation method. For fixed fin height, the optimum fin length and efficiency are arbitrarily defined as those for which the heat loss is in the range between 90% and 99% of the maximum heat loss. The maximum heat loss, the maximum effectiveness, the minimum fin resistance, the optimum fin length and the optimum efficiency are presented as a function of the inside fluid convection characteristic number, fin base thickness, fin height and ambient convection characteristic number. One of the results shows that the optimum fin length decreases almost linearly with the increase of the fin base thickness.

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Performance analysis and optimization of elliptic fins circumscribing a circular tube

Cited by 47 publications

References 12 publications

Numerical Study of Flow Over Annular Elliptical Finned Tube Heat Exchangers

Numerical Study of Flow Over Annular Elliptical Finned Tube Heat Exchangers

Simple Correlation to Evaluate Efficiency of Annular Elliptical Fin Circumscribing Circular Tube

Optimization of a rectangular profile annular fin based on fixed fin height

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