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Numerical Study of Flow and Heat Transfer with ZnO-Water Nanofluid in Flattened Tubes

  • Mark Wing Tsan Lee and Kumar Perumal ORCID logo EMAIL logo
Published/Copyright: October 31, 2019
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Abstract

The usage of nanofluids and modification of tube geometry are the two most prominent heat transfer enhancement methods employed to improve the performance of thermal devices. In this work, the combined effect of these methods has been studied by CFD modelling of developing and Graetz laminar flow in flattened tubes with ZnO – water nanofluid. For the purpose of comparison, simulation with water and circular tube has also been carried out. Performance evaluation has been done using PEC, PER and entropy generation. Results reveal that tube flattening has more pronounced effect on both heat transfer and flow compared to that of nanofluid. An optimum tube flattening in terms of aspect ratio and nanofluid concentration has also been identified for this kind of flow. Flattened tube with aspect ratio 6 with 1 % ZnO-water nanofluid has been found to yield the highest entropy generation reduction of 13.24 %

Nomenclature

Greek Symbols
Α

Thermal diffusivity (m2/s)

β

Fraction of liquid volume travelling with a particle

γ

Ratio of nanolayer thermal conductivity to particle conductivity

δ

Distance between nanoparticles (m)

Є

Aspect ratio of geometry cross-sectional height to width

μ

Dynamic viscosity (Pa.s)

ρ

Density (kg/m3)

ϕ

Volume fraction

χ

Ratio of the nanolayer thickness to the particle radius

ψ

Particle sphericity

τ

Dimensionless wall and fluid temperature difference

λ

Dimensionless length of circular tube

φ

Total dimensionless entropy

Latin Symbols
A

Area (m2)

AR

Aspect ratio

c

Correction factor

C

Specific heat capacity (J/ kg K)

C1

Constant

Cf

Skin friction coefficient

d

Diameter

Ec

Eckart number

f

Darcy’s friction factor

fr

Friction coefficient

h

Convective heat transfer coefficient (W/m2K)

k

Thermal conductivity (W/mK)

K

Boltzmann constant, 1.381 × 10−23 J/K

kpe

Equivalent thermal conductivity (W/mK)

L

Length of channel (m)

m

Mass flow rate (kg/s)

n

Empirical shape factor

Nu

Nusselt number

OS

Occupied space (m2)

P

Perimeter

PEC

performance evaluation criterion

PER

performance enhancement ratio

ΔP

Pressure drop (Pa)

Pr

Prandtl number

Q

Heat transfer (W)

q

Heat flux (W/m2)

Re

Reynolds number

Sgen

Entropy generation

T

Temperature (K)

To

Reference temperature, 273 K

u

Fluid velocity (m/s)

V

Volume (m3)

Volumetric flow rate (m3)

W

Pumping power (W)

Subscripts
b

Bulk

bf

Base fluid

c

Cross-sectional

f

Fluid

h

Hydraulic

in

Inlet

LMTD

Logarithmic Mean Temperature Difference

max

Maximum value

nf

Nanofluid

out

Outlet

p

Nanoparticle

s

Surface

w

water

References

[1] Kakac S, Liu H. 1998. Heat exchangers: Selection, rating, and thermal design. CRC-Press. Retrieved from: https://books.google.com.my/books?id=wW-7QgAACAAJ.Search in Google Scholar

[2] Andrzejczyk R, Muszynski T, Kozak P. 2018. Experimental investigation on straight and u-bend double tube heat exchanger with active and passive enhancement methods. MATEC Web of Conferences. Les Ulis: EDP Sciences.10.1051/matecconf/201824002001Search in Google Scholar

[3] Sajadi AR, Kowsary F, Bijarchi MA, Sorkhabi YDS. Experimental and numerical study on heat transfer, flow resistance, and compactness of alternating flattened tubes. Appl Thermal Eng. 2016;108:740–50.10.1016/j.applthermaleng.2016.07.033Search in Google Scholar

[4] Pradeep T. Textbook of nanoscience and nanotechnology/by T. Pradeep. New York, N.Y: McGraw-Hill Education LLC, 2012.Search in Google Scholar

[5] Singh DK, Pandey DK, Yadav RR, Singh D. 2013. A study of ZnO nanoparticles and ZnO-EG nanofluid. J Exp Nanosci. 8;731–41. Taylor & Francis. Retrieved from : https://doi.org/10.1080/17458080.2011.602369.Search in Google Scholar

[6] Gangwar J, Gupta B, Srivastava A. Prospects of emerging engineered oxide nanomaterials and their applications. Def Sci J. 2016;66:323–40.10.14429/dsj.66.10206Search in Google Scholar

[7] Huminic G, Huminic A. Application of nanofluids in heat exchangers: A review. Appl Nanofluids Heat Exch A Rev. 2012;16:5625–38.10.1016/j.rser.2012.05.023Search in Google Scholar

[8] Zhao N, Yang J, Li H, Zhang Z, Li S. Numerical investigations of laminar heat transfer and flow performance of Al2O3–water nanofluids in a flat tube. Int J Heat Mass Transf. 2016;92:268–82.10.1016/j.ijheatmasstransfer.2015.08.098Search in Google Scholar

[9] Bahiraei M, Rahmani R, Yaghoobi A, Khodabandeh E, Mashayekhi R, Amani M. Recent research contributions concerning use of nanofluids in heat exchangers: A critical review. Appl Thermal Eng. 2018;133:137–59.10.1016/j.applthermaleng.2018.01.041Search in Google Scholar

[10] Tibiriçá CB, Ribatski G, Thome JR. Saturated flow boiling heat transfer and critical heat flux in small horizontal flattened tubes. Int J Heat Mass Transf. 2012;55:7873–83.10.1016/j.ijheatmasstransfer.2012.08.017Search in Google Scholar

[11] Razi P, Akhavan-Behabadi MA, Saeedinia M. Pressure drop and thermal characteristics of CuO–base oil nanofluid laminar flow in flattened tubes under constant heat flux. Int Commun Heat Mass Transfer. 2011;38:964–71.10.1016/j.icheatmasstransfer.2011.04.010Search in Google Scholar

[12] Akhavan-Behabadi MA, Sadoughi MK, Darzi M, Fakoor-Pakdaman M, Abbasi A. Simultaneous effects of flattening tube and adding nanoparticles on boiling heat transfer. J Thermophys Heat Transfer. 2017;31:78–85.10.2514/1.T4612Search in Google Scholar

[13] Safikhani H, Abbassi A. Effects of tube flattening on the fluid dynamic and heat transfer performance of nanofluids. Adv Powder Technol. 2014;25:3.10.1016/j.apt.2014.02.018Search in Google Scholar

[14] Delavari V, Hashemabadi SH. CFD simulation of heat transfer enhancement of Al2O3/water and Al2O3/ethylene glycol nanofluids in a car radiator. Appl Thermal Eng. 2014;73:380–90.10.1016/j.applthermaleng.2014.07.061Search in Google Scholar

[15] Haghshenas F, Talaie M, Nasr S. Numerical and experimental investigation of heat transfer of ZnO/Water nanofluid in the concentric tube and plate heat exchangers. Thermal Sci. 2011;15:183–94.10.2298/TSCI091103048H.10.2298/TSCI091103048HSearch in Google Scholar

[16] Sharma K, Sarm P, Azmi W, Mamat R, Kadirgama K. Correlations to predict friction and forced convection heat transfer coefficients of water based nanofluids for turbulent flow in a tube. Int J Microscale Nanoscale Thermal Fluid Transp Phenom. 2012;3:283–307. Hauppauge.Search in Google Scholar

[17] Sieder EN, Tate GE. Heat transfer and pressure drop of liquids in tubes. Ind Eng Chem. 1936;28:1429–35.10.1021/ie50324a027Search in Google Scholar

[18] Incropera FP. Fundamentals of heat and mass transfer/Frank P. Incropera … [et al.]. 6th ed. Hoboken, NJ: John Wiley, 2007.Search in Google Scholar

[19] Muzychka Y, Yovanovich M. Laminar forced convection heat transfer in the combined entry region of non-circular ducts. (Y. Muzychka, Ed. J Heat Transfer (Trans ASME). 2004;126:54–61.10.1115/1.1643752Search in Google Scholar

[20] Mills AF. Heat transfer/A.F. Mills. 2nd ed. Upper Saddle River, N.J: Prentice Hall, 1999.Search in Google Scholar

[21] Ferrouillat S, Bontemps A, Ribeiro J-P, Gruss J-A, Soriano O. Hydraulic and heat transfer study of SiO 2/water nanofluids in horizontal tubes with imposed wall temperature boundary conditions. Int J Heat Fluid Flow. 2011;32:424–39.10.1016/j.ijheatfluidflow.2011.01.003Search in Google Scholar

[22] Leong KY, Saidur R, Mahlia TMI, Yau YH. Entropy generation analysis of nanofluid flow in a circular tube subjected to constant wall temperature. Int Commun Heat Mass Transfer. 2012;39:1169–75.10.1016/j.icheatmasstransfer.2012.06.009Search in Google Scholar

[23] Huminic G, Huminic A. The heat transfer performances and entropy generation analysis of hybrid nanofluids in a flattened tube. Int J Heat Mass Transf. 2018;119:813. Oxford.10.1016/j.ijheatmasstransfer.2017.11.155Search in Google Scholar

[24] Sciacovelli A, Verda V, Sciubba E. Entropy generation analysisasa design tool—A review. Renew Sustain Energy Rev. 2015;43:1167–81.10.1016/j.rser.2014.11.104Search in Google Scholar

[25] Sajadi A, Sadati S, Nourimotlagh M, Pakbaz O, Ashtiani D, Kowsari F. Experimental study on turbulent convective heat transfer, pressure drop, and thermal performance characterization of ZnO/water nanofluid flow in a circular tube. (A. Sajadi, Ed.). Thermal Sci. 2014;18:1315–26.10.2298/TSCI131114022SSearch in Google Scholar

[26] Ali HM, Ali H, Liaquat H, Bin Maqsood HT, Nadir MA. Experimental investigation of convective heat transfer augmentation for car radiator using ZnO–water nanofluids. Energy. 2015;84:317–24.10.1016/j.energy.2015.02.103Search in Google Scholar

Received: 2019-07-03
Revised: 2019-09-16
Accepted: 2019-10-05
Published Online: 2019-10-31

© 2019 Walter de Gruyter GmbH, Berlin/Boston

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