0
Research Papers

Combined Energy and Exergy Analysis of a Nonisothermal Fin Array With Non-Boussinésq Variable Property Fluid

[+] Author and Article Information
Biplab Das

Department of Mechanical Engineering,
National Institute of Technology, Silchar,
Silchar, Assam 788010, India
e-mail: biplab.2kmech@gmail.com

Asis Giri

Department of Mechanical Engineering,
North Eastern Regional Institute of Science
and Technology,
Nirjuli, Arunachal Pradesh 791109, India

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF THERMAL SCIENCE AND ENGINEERING APPLICATIONS. Manuscript received November 5, 2015; final manuscript received February 19, 2016; published online April 26, 2016. Assoc. Editor: Hongbin Ma.

J. Thermal Sci. Eng. Appl 8(3), 031010 (Apr 26, 2016) (12 pages) Paper No: TSEA-15-1316; doi: 10.1115/1.4033012 History: Received November 05, 2015; Revised February 19, 2016

To transport the energy efficiently without much dissipation, first and second law analyses of mixed convection heat transport from an array of nonisothermal rectangular vertical plate-finned heat sink are made using purely computational fluid dynamics (CFD) analysis on the governing equations. Report provides the dependence of Nusselt number, entropy production, pumping power ratio (PPR), and flow bypass factor (BF) on the inlet velocity, fin conductance parameter, thermal Grashof number (Gr), dimensionless clearance (C*), and dimensionless fin spacing (S*). Total nondimensional entropy production is found to decrease continuously with clearances for all fin spacings, except at the lowest fin spacing involving lowest Gr (= 1.8 × 105). On the other hand, at higher inlet velocities, Nusselt number indicates an optimum value with clearances. Optimum Nusselt number is found to observe in a range of S*= 0.2–0.3 for all Gr. For smaller fin spacing, PPR is noticeably higher, but at the optimum value of fin spacing, PPR reduces roughly by an order of magnitude. Interestingly, flow bypass is remarkably lower at the optimum clearance. Finally, correlation of friction factor, PPR, and entropy generation is presented.

FIGURES IN THIS ARTICLE
<>
Copyright © 2016 by ASME
Your Session has timed out. Please sign back in to continue.

References

Figures

Grahic Jump Location
Fig. 1

(a) Schematic of mixed convection heat transfer from the vertical plate-finned heat sink and (b) computational domain

Grahic Jump Location
Fig. 2

Local Nusselt number (Nuyz) variation over the fin surface, kfin = 75 W/m K, Gr = 4.3 × 105, Win.mix = 1707, and C*= 0.1: (a) S*= 0.1, (b) S*= 0.2, and (c) S*= 0.3

Grahic Jump Location
Fig. 3

Local Nusselt number (Nuyz) variation over the fin surface, kfin = 150 W/m K, Gr = 4.3 × 105, Win.mix = 1707, and C*= 0.1: (a) S*= 0.1, (b) S*= 0.2, and (c) S*= 0.3

Grahic Jump Location
Fig. 4

Local Nusselt number (Nuyz) variation over the fin surface kfin = 75 W/m K, Gr = 8.4 × 105, Win.mix = 2133, and C*= 0.1: (a) S*= 0.1, (b) S*= 0.2, and (c) S*= 0.3

Grahic Jump Location
Fig. 5

Local Nusselt number (Nuyz) variation along the fin height: (a) S*= 0.1, Z = 1.225 and (b) S*= 0.2 and S*= 0.3, Z = 0.98

Grahic Jump Location
Fig. 6

Development of volumetric rate of local dimensionless entropy generation at different axial locations for kfin = 75 W/m K, Gr = 8.4 × 105, Win,mix = 2400, and T0*  = 3.66. (a) S*= 0.1, Z = 0.029, and C*= 0.05; (b) S*= 0.1, Z = 0.91, and C*= 0.05; (c) S*= 0.1, Z = 4.08, and C*= 0.05; (d) S*= 0.1, Z = 11.36, and C*= 0.05; (e) S*= 0.3, C*= 0.075, and Z = 0.029; (f) S*= 0.3, C*= 0.075, and Z = 0.91; (g) S*= 0.3, C*= 0.075, and Z = 4.08; and (h) S*= 0.3, C*= 0.075, and Z = 11.36.

Grahic Jump Location
Fig. 7

Variation of total dimensionless entropy generation and overall Nusselt number at different inlet mixed convection velocities for T0*  = 3.66 with kfin = 75 W/m K. (a) S*= 0.1, Gr = 1.8 × 105; (b) S*= 0.1, Gr = 8.4 × 105; (c) S*= 0.3, Gr = 1.8 × 105; (d) S*= 0.3, Gr = 8.4 × 105; (e) S*= 0.5, Gr = 1.8 × 105; and (f) S*= 0.5, Gr = 8.4 × 105.

Grahic Jump Location
Fig. 8

Variation of total dimensionless entropy generation and overall Nusselt number at different inlet mixed convection velocities for T0*  = 3.66: (a) kfin = 75 W/m K, Gr = 1.8 × 105, and C*= 0.075 and (b) kfin = 75 W/m K, Gr = 8.4 × 105, and C*= 0.15

Grahic Jump Location
Fig. 9

Correlation of total dimensionless entropy generation with the governing parameters

Grahic Jump Location
Fig. 10

Variation of PPR with clearances for nonisothermal fin, kfin = 75 W/m K, T0*  = 3.66: (a) S*= 0.1, (b) S*= 0.2, (c) S*= 0.3, and (d) S*= 0.5

Grahic Jump Location
Fig. 11

(a) Correlation of PPR with the governing parameters and (b) correlation of friction factor with the governing parameters

Grahic Jump Location
Fig. 12

Axial variation of flow BF, T0*  = 3.66, kfin = 75 W/m K. (a) S*= 0.1, Gr = 8.4 × 105; (b) S*= 0.2, Gr = 8.4 × 105; (c) S*= 0.3, Gr = 8.4 × 105; (d) S*= 0.5, Gr = 8.4 × 105, (e) S*= 0.1, Gr = 4.3 × 105; (f) S*= 0.2, Gr = 4.3 × 105; (g) S*= 0.3, Gr = 4.3 × 105; and (h) S*= 0.5, Gr = 4.3 × 105.

Tables

Errata

Discussions

Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In