## THERMAL SCIENCE

International Scientific Journal

### Thermal Science - Online First

online first only
### Heat transfer enhancement using non-equally structure in a plate-fin heat exchanger with offset fins

**ABSTRACT**

In this study, a cross flow plate-fin heat exchanger with offset fins is optimized by considering the effects of flow maldistribution for air side. For this purpose, the study is focused on an increase in the rate of heat transfer, which can be achieved by using non-equally fin structure. Numerical simulations have been carried out to investigate the thermodynamic characteristics of the non-equally full-size PFHE by using the porous media approach. Based on the numerical model, flow distribution, total heat rate and pressure drop of the PFHE are studied. A asymmetric structure with heat transfer enhancement is presented in this study. After comparing numerical predictions of the total heat transfer rate and the pressure drop under various Reynolds number. It is observed that, the percentages of increase in effectiveness for the final non-equally structure are in the range of 2.5%-6.2% and the pressure drop remains almost constant in the cases of air inlet velocity fixed at 9.5627 m/s. The increasing asymmetric structure is numerically verified to improve the flow distribution of the PFHE.

**KEYWORDS**

PAPER SUBMITTED: 2021-12-27

PAPER REVISED: 2022-01-29

PAPER ACCEPTED: 2022-02-28

PUBLISHED ONLINE: 2022-03-05

- A.Lemouedda, et al.,Optimizaton of the angle of attack of delta-winglet vortex generators in a plate-fin-and-tube heat exchanger, Int.J.Heat Mass Tran.. 53(2010), pp. 5386-5399.
- Ke Wel Song, et al. The optimal arrangement of vortex generators for best heat transfer enhancement in flat-tube-fin heat exchanger, Int.J.Therm.Sci. 132 (2018), pp. 132:355-367.
- L.O.Salviano, et al.,Thermal-hydraulic performance optimization of inline and staggered fin-tube compact heat exchangers applying longitudinal vortex generators. Appl.Therm.eng. 95(2016), pp. 311-329.
- Muhammad Awais, et al., Enhancement of thermal and hydraulic performance of compact finned-tube heat exchanger using vortex generators(VGs): a parametric study. Int.J.Therm.Sci.140(2019), pp. 154-166.
- Hemant Naik, et al., Thermal performance analysis of fin-tube heat exchanger with staggered tube arrangement in presence of rectangular winglet pairs, Int. J. Heat and Mass Tran. 2021,16106723
- Hemant Naik, et al. Effect of rectangular winglet pair in common flow down configuration on heat transfer from an isothermal heated plate, Heat Tran.eng. 39(2018),pp.1774-1789.
- Anupam Sinha, Himadri Chattopadhyay, Ashwin Kannan Iyengar,et al. Enhancement of heat transfer in a fin-tube heat exchanger using rectangular winglet type vortex generators.Int. J. Heat and Mass Tran.,101(2016), pp. 667-681.
- Patankar,S.V., Spalding,D.B. Heat exchanger design theory source book New York: McGraw-Hill Book Company.
- SEPIDEH ESMAEILI RAD, HOSSEIN AFSHIN, BIJAN FARHANIEH, Heat Transfer Enhancement in Shell and Tube Heat Exchangers Using Porous Media. Heat Tran. Eng. 36(2015),3, pp. 262-277.
- Sandeep Koundinya, Vigneshkumar N, et.al., Computational and experimental study of fluid flow and heat flow characteristics in porous media, Materials Sci. and Eng. 2016,1(149):012222.
- Buyruk, E., Karabulut, K. Numerical Investigation into Heat Transfer for Three-Dimensional Plate Fin Heat Exchangers with Fins Placed Perpendicular to Flow. Transactions of FAMENA,,37(2013), 2, pp. 87-102.
- Buyruk, E., Karabulut, K, Karabulut, Ö.O. Three-Dimensional Numerical Investigation of Heat Transfer for Plate Fin Heat Exchangers. Heat Mass Trans. 49(2013),6, pp. 817-826.
- Qinguo Zhang,Sicheng Qin, et.al., Simulation and experimental investigation of the wavy fin-and-tube intercooler. Case Studies in Thermal Engineering. 8(2016), pp.32-40.
- Weiping Wang, et.al., Numerical study on hydrodynamic characteristics of plate-fin heat exchanger using porous media approach, Comp. and Chemical Eng. 61(2014), pp.30-37.
- Marilena Musto, Nicola Bianco, et.al. A simplified methodology to simulate a heat exchanger in an aircraft's oil cooler by means of a Porous Media model. Appl. Therm. Eng. 2016, 94:836-845.
- Zhen-zhong Li,Yu-dong Ding,et.al. An approach based on the porous media model for numerical simulation of 3D finned-tubes heat exchanger. Int. J. Heat Mass Tran. 173(2021),121226.
- SahinB,Yakut K, Kotcioglu I, et.al. Optimum design parameters of a heat exchanger. Appl. Energy. 82(2005), pp. 90-106.
- Muhammad Mahmood Aslam Bhutta, et.al. CFD applications in various heat exchangers design: A review. Appl. Therm. Eng.32(2012), pp. 1-12.
- Zhe Zhang ,Sunil Mehendale, et.al. Experimental invsetigation of distributor configuration on flow maldistribution in plate-fin heat exchangers. Applied Thermal Engineering. 25(2015),85, pp.111-23.
- Manglik R M,Bergles A E. The thermal-hydraulic design of the rectangular offset-strip-fin compact heat exchanger.R.K.shahet al., Eds.Hemisphere,New York, 1990:123-149.
- Wahiba Yaici, Mohamed Ghorab,Evgueniy Entchev. 3D study of the effect of inlet air flow maldistribution on plate-fin-tube heat exchanger design and thermal-hydraulic performance. Int. J. Heat and Mass Trans. 2016, 101:527-541.
- Buyruk, E., Karabulut, K. Research of Heat Transfer Augmentation in Plate Fin Heat Exchangers Having Different Fin Types, Journal of Engineering Thermophysics, 29(2020), 2, pp. 316-330.
- Muller-Menzel,T., H echt, T. Plate-fin heat exchanger performance reduction in special two-phase flow conditions,Cryogenics,35(1995),pp.297-301.
- Hassan Hajabdollahi, Sajjad Seifoori. Effect of flow maldistribution in the optimal design of a cross flow heat exchanger. Int.J. Therm. Sci. 109(2016), pp.242-252.
- Blecich, Paolo. Experimental investigation of the effects of airflow nonuniformity on performance of a fin-and-tube heat exchanger. International Journal of Refrigeration. 59(2015),pp.65-74.
- Ranganayakulu,C., Seetharamu,K.N. The combined effects of wall longitudinal heat conduction and inlet fluid flow maldistribution in crossflow plate-fin heat exchangers. Heat Mass Trans. 36(2000),30, pp. 247-256.
- Juan Du, Zuo-Qin Qian, Zhong-Yuan Dai. Experimental study and numerical simulation of flow and heat transfer performance on an offset plate-fin heat exchanger. Heat and Mass Transfer.52(2015),pp. 1791-1806.
- Du Juan, Yang Man-Ni,Yang Shi-Feng. Correlations and optimization of a heat exchanger with offset fins by genetic algorithm combining orthogonal design. Appl.Therm.eng.107(2016), pp.1091-1103.