0
Research Papers: Heat Exchangers

# Analysis of the Fin Performance of Offset Strip Fins Used in Plate-Fin Heat Exchangers

[+] Author and Article Information
Yujie Yang

State Key Laboratory of Power Engineering and
Multiphase Flow,
Department of Refrigeration and
Cryogenic Engineering,
School of Energy and Power Engineering,
Xi'an Jiaotong University,
Xi'an 710049, China
e-mail: yyj_898@stu.xjtu.edu.cn

Yanzhong Li

State Key Laboratory of Power Engineering and
Multiphase Flow,
Department of Refrigeration and
Cryogenic Engineering,
School of Energy and Power Engineering,
Xi'an Jiaotong University,
Xi'an 710049, China
e-mail: yzli-epe@mail.xjtu.edu.cn

Biao Si

Department of Refrigeration and
Cryogenic Engineering,
School of Energy and Power Engineering,
Xi'an Jiaotong University,
Xi'an 710049, China
e-mail: si.biao@stu.xjtu.edu.cn

Jieyu Zheng

Department of Refrigeration and
Cryogenic Engineering,
School of Energy and Power Engineering,
Xi'an Jiaotong University,
Xi'an 710049, China
e-mail: zjy.521331@stu.xjtu.edu.cn

Rui Kang

Department of Refrigeration and
Cryogenic Engineering,
School of Energy and Power Engineering,
Xi'an Jiaotong University,
Xi'an 710049, China
e-mail: kangrui996996@stu.xjtu.edu.cn

1Corresponding author.

Contributed by the Heat Transfer Division of ASME for publication in the JOURNAL OF HEAT TRANSFER. Manuscript received August 11, 2015; final manuscript received May 5, 2016; published online June 7, 2016. Assoc. Editor: Danesh / D. K. Tafti.

J. Heat Transfer 138(10), 101801 (Jun 07, 2016) (9 pages) Paper No: HT-15-1540; doi: 10.1115/1.4033615 History: Received August 11, 2015; Revised May 05, 2016

## Abstract

As an important consideration in the design of plate-fin heat exchangers, the selection of plate-fin surfaces is associated with the estimation of the fin performance in many cases. The fin performance of offset strip fin (OSF) and plain fin is numerically investigated with well-validated 3D models in the present study. The comparative analysis shows that the conventional fin efficiency and fin effectiveness concepts provide an incomplete assessment of the fin performance of the fins, and lead to impractical suggestions of using OSF fin. Further investigation indicates that the idealization of uniform heat transfer coefficient over all the surfaces in fin channel, which runs through the conventional concepts, is untenable, and strongly restricts the fin performance analysis. An actual fin effectiveness is then proposed to measure the fin performance. It physically represents the ratio of the heat flux over the fin surfaces and that over the primary surfaces in the fin channel. With this method, the effects of the geometrical parameters of the OSF are discussed carefully. The results show that there exists a specific fin thickness-to-height ratio α and fin density γ, which contribute to the highest fin performance for a given mass flux, and the optimal γ (or α) increases (or decreases) as mass flux increases. The OSF fins with relatively large fin thickness-to-length ratio δ perform better in low Re region and the optimum δ decreases with the increasing Re number.

<>

## References

Webb, R. L. , 1981, “ Performance Evaluation Criteria for Use of Enhanced Heat Transfer Surfaces in Heat Exchanger Design,” Int. J. Heat Mass Transfer, 24(4), pp. 715–726.
Gardner, K. A. , 1945, “ Efficiency of Extended Surface,” Trans. ASME, 67, pp. 621–631.
Schmidt, T. E. , 1949, “ Heat Transfer Calculations for Extended Surfaces,” Refrig. Eng., 57, pp. 351–357.
Hashizume, K. , Sato, T. , Matsue, T. , and Koyama, T. , 2004, “ Fin Efficiency of Serrated Fins Part 4. Correction Factor for Inline Arrangement,” Heat Transfer—Asian Res., 33(4), pp. 258–269.
Hashizume, K. , Morikawa, R. , Koyama, T. , and Matsue, T. , 2002, “ Fin Efficiency of Serrated Fins,” Heat Transfer Eng., 23(2), pp. 6–14.
Hashizume, K. , and Matsue, T. , 1999, “ Fin Efficiency of Serrated Fins: Part 1. Analysis of Theoretical Fin Efficiency and Experimental Results,” Heat Transfer—Asian Res., 28(6), pp. 528–540.
Wang, C. C. , Lee, C. J. , Chang, C. T. , and Lin, S. P. , 1999, “ Heat Transfer and Friction Correlation for Compact Louvered Fin-and-Tube Heat Exchangers,” Int. J. Heat Mass Transfer, 42(11), pp. 1945–1956.
Tao, Y. B. , He, Y. L. , Huang, J. , Wu, Z. G. , and Tao, W. Q. , 2007, “ Numerical Study of Local Heat Transfer Coefficient and Fin Efficiency of Wavy Fin-and-Tube Heat Exchangers,” Int. J. Therm. Sci., 46(8), pp. 768–778.
Cortés, C. , Díez, L. I. , and Campo, A. , 2008, “ Efficiency of Composite Fins of Variable Thickness,” Int. J. Heat Mass Transfer, 51(9–10), pp. 2153–2166.
Song, K. W. , Wang, Y. , Zhang, Q. , Wang, L. B. , and Liu, Y. J. , 2011, “ Numerical Study of the Fin Efficiency and a Modified Fin Efficiency Formula for Flat Tube Bank Fin Heat Exchanger,” Int. J. Heat Mass Transfer, 54(11–12), pp. 2661–2672.
Prasad, B. S. V. , 1996, “ Fin Efficiency and Mechanisms of Heat Exchange Through Fins in Multi-Stream Plate-Fin Heat Exchangers: Formulation,” Int. J. Heat Mass Transfer, 39(2), pp. 419–428.
Manglik, R. M. , Huzayyin, O. A. , and Jog, M. A. , 2011, “ Fin Effects in Flow Channels of Plate-Fin Compact Heat Exchanger Cores,” ASME J. Therm. Sci. Eng. Appl., 3(4), p. 041004.
Huang, L. J. , and Shah, R. K. , 1992, “ Assessment of Calculation Methods for Efficiency of Straight Fins of Rectangular Profile,” Int. J. Heat Fluid Flow, 13(3), pp. 282–293.
Aziz, A. , and Beers-Green, A. B. , 2009, “ Performance and Optimum Design of Convective–Radiative Rectangular Fin With Convective Base Heating, Wall Conduction Resistance, and Contact Resistance Between the Wall and the Fin Base,” Energy Convers. Manage., 50(10), pp. 2622–2631.
Braga, C. V. M. , and Saboya, F. E. M. , 1999, “ Turbulent Heat Transfer, Pressure Drop and Fin Efficiency in Annular Regions With Continuous Longitudinal Rectangular Fins,” Exp. Therm. Fluid Sci., 20(2), pp. 55–65.
Mokheimer, E. M. A. , 2002, “ Performance of Annular Fins With Different Profiles Subject to Variable Heat Transfer Coefficient,” Int. J. Heat Mass Transfer, 45(17), pp. 3631–3642.
Agwu-Nnanna, A. G. , Haji-Sheikh, A. , and Agonafer, D. , 2003, “ Effect of Variable Heat Transfer Coefficient, Fin Geometry, and Curvature on the Thermal Performance of Extended Surfaces,” ASME J. Electron. Packag., 125(3), pp. 456–460.
Singla, R. K. , and Das, R. , 2015, “ Adomian Decomposition Method for a Stepped Fin With All Temperature-Dependent Modes of Heat Transfer,” Int. J. Heat Mass Transfer, 82, pp. 447–459.
Arslanturk, C. , 2005, “ A Decomposition Method for Fin Efficiency of Convective Straight Fins With Temperature-Dependent Thermal Conductivity,” Int. Commun. Heat Mass Transfer, 32(6), pp. 831–841.
Torabi, M. , and Yaghoobi, H. , 2014, “ Two Dominant Analytical Methods for Thermal Analysis of Convective Step Fin With Variable Thermal Conductivity,” Therm. Sci., 18(2), pp. 431–442.
Joneidi, A. A. , Ganji, D. D. , and Babaelahi, M. , 2009, “ Differential Transformation Method to Determine Fin Efficiency of Convective Straight Fins With Temperature Dependent Thermal Conductivity,” Int. Commun. Heat Mass Transfer, 36(7), pp. 757–762.
Fouladi, F. , Hosseinzadeh, E. , Barari, A. , and Domairry, G. , 2010, “ Highly Nonlinear Temperature-Dependent Fin Analysis by Variational Iteration Method,” Heat Transfer Res., 41(2), pp. 155–165.
Coşkun, S. B. , and Atay, M. T. , 2008, “ Fin Efficiency Analysis of Convective Straight Fins With Temperature Dependent Thermal Conductivity Using Variational Iteration Method,” Appl. Therm. Eng., 28(17–18), pp. 2345–2352.
Ganji, D. D. , Rahimi, M. , and Rahgoshay, M. , 2012, “ Determining the Fin Efficiency of Convective Straight Fins With Temperature Dependent Thermal Conductivity by Using Homotopy Perturbation Method,” Int. J. Numer. Methods Heat Fluid Flow, 22(2), pp. 263–272.
Inc, M. , 2008, “ Application of Homotopy Analysis Method for Fin Efficiency of Convective Straight Fins With Temperature-Dependent Thermal Conductivity,” Math. Comput. Simul., 79(2), pp. 189–200.
Rajabi, A. , 2007, “ Homotopy Perturbation Method for Fin Efficiency of Convective Straight Fins With Temperature-Dependent Thermal Conductivity,” Phys. Lett. A, 364(1), pp. 33–37.
Duan, J. S. , Wang, Z. , Fu, S. Z. , and Chaolu, T. , 2013, “ Parameterized Temperature Distribution and Efficiency of Convective Straight Fin With Temperature-Dependent Thermal Conductivity by a New Modified Decomposition Method,” Int. J. Heat Mass Transfer, 59, pp. 137–143.
Peng, H.-S. , and Chen, C.-L. , 2011, “ Hybrid Differential Transformation and Finite Difference Method to Annular Fin With Temperature-Dependent Thermal Conductivity,” Int. J. Heat Mass Transfer, 54(11–12), pp. 2427–2433.
Kulkarni, D. B. , and Joglekar, M. M. , 2009, “ Residue Minimization Technique to Analyze the Efficiency of Convective Straight Fins Having Temperature-Dependent Thermal Conductivity,” Appl. Math. Comput., 215(6), pp. 2184–2191.
Wang, Y. , Wang, L.-C. , Lin, Z.-M. , Yao, Y.-H. , and Wang, L.-B. , 2012, “ The Condition Requiring Conjugate Numerical Method in Study of Heat Transfer Characteristics of Tube Bank Fin Heat Exchanger,” Int. J. Heat Mass Transfer, 55(9–10), pp. 2353–2364.
Ameel, B. , Huisseune, H. , Degroote, J. , T'Joen, C. , Jaeger, P. D. , Vierendeels, J. , and Paepe, M. D. , 2013, “ On Fin Efficiency in Interrupted Fin and Tube Heat Exchangers,” Int. J. Heat Mass Transfer, 60, pp. 557–566.
Bergman, T. L. , Lavine, A. S. , Incropera, F. P. , and Dewitt, D. P. , 2011, Fundamentals of Heat and Mass Transfer, 7th ed., Wiley, Hoboken, NJ.
Kundu, B. , and Das, P. K. , 2009, “ Performance and Optimum Design Analysis of Convective Fin Arrays Attached to Flat and Curved Primary Surfaces,” Int. J. Refrig., 32(3), pp. 430–443.
Kays, W. M. , and London, A. L. , 1984, Compact Heat Exchangers, 3rd ed., McGraw-Hill, New York.
Manglik, R. M. , and Bergles, A. E. , 1995, “ Heat Transfer and Pressure Drop Correlations for the Rectangular OSF Fin Compact Heat Exchanger,” Exp. Therm. Fluid Sci., 10(2), pp. 171–180.
Dong, J. Q. , Chen, J. P. , Chen, Z. J. , and Zhou, Y. M. , 2007, “ Air-Side Thermal Hydraulic Performance of OSF Fin Aluminum Heat Exchangers,” Appl. Therm. Eng., 27(2–3), pp. 306–313.
Yang, Y. J. , and Li, Y. Z. , 2014, “ General Prediction of the Thermal Hydraulic Performance for Plate-Fin Heat Exchanger With Offset Strip Fins,” Int. J. Heat Mass Transfer, 78, pp. 860–870.

## Figures

Fig. 1

The geometries of OSF fin and plain fin (a) offset strip fin and (b) plain fin

Fig. 2

The computational domains for OSF fin and plain fin

Fig. 3

Mesh generation in the computational domain (partial region)

Fig. 4

Comparison of the numerical results and the experimental data for the plain fins

Fig. 5

Comparison of the numerical results and the experimental data for the OSF fins

Fig. 6

Behavior of the defined fin efficiency in terms of Re number for the plate fins

Fig. 7

Behavior of the ideal fin efficiency in terms of Re number for the plate fins

Fig. 8

The positions of the surfaces in the analysis of local data

Fig. 9

Local dimensionless temperature difference on the secondary fin surface

Fig. 10

Local heat transfer coefficient on the secondary fin surface

Fig. 11

Behavior of conventional fin effectiveness in terms of Re number for the plate fins

Fig. 12

Local dimensionless temperature difference over the heat transfer surfaces of OSF fin

Fig. 13

Local dimensionless temperature difference over the heat transfer surfaces of plain fin

Fig. 14

Local heat transfer coefficient over the heat transfer surfaces of OSF fin

Fig. 15

Local heat transfer coefficient over the heat transfer surfaces of plain fin

Fig. 16

Behavior of the actual fin effectiveness in terms of Reynolds number

Fig. 17

The front-fin-end area Affe of OSF fins

Fig. 18

εf,act versus γ with Affe/t2 as a parameter for OSF fins

Fig. 19

εf,act versus γ with mass flux G as a parameter for OSF fins

Fig. 20

Actual fin effectiveness of OSF fin in terms of fin thickness-to-length ratio

## Errata

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 Proceedings Articles
Related eBook Content
Topic Collections