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Particle agglomeration and properties of nanofluids

  • Yijun Yang
  • Alparslan Oztekin
  • Sudhakar Neti
  • Satish Mohapatra
Research Paper

Abstract

The present study demonstrates the importance of actual agglomerated particle size in the nanofluid and its effect on the fluid properties. The current work deals with 5 to 100 nm nanoparticles dispersed in fluids that resulted in 200 to 800 nm agglomerates. Particle size distributions for a range of nanofluids are measured by dynamic light scattering (DLS). Wet scanning electron microscopy method is used to visualize agglomerated particles in the dispersed state and to confirm particle size measurements by DLS. Our results show that a combination of base fluid chemistry and nanoparticle type is very important to create stable nanofluids. Several nanofluids resulted in stable state without any stabilizers, but in the long term had agglomerations of 250 % over a 2 month period. The effects of agglomeration on the thermal and rheological properties are presented for several types of nanoparticle and base fluid chemistries. Despite using nanodiamond particles with high thermal conductivity and a very sensitive laser flash thermal conductivity measurement technique, no anomalous increases of thermal conductivity was measured. The thermal conductivity increases of nanofluid with the particle concentration are as those predicted by Maxwell and Bruggeman models. The level of agglomeration of nanoparticles hardly influenced the thermal conductivity of the nanofluid. The viscosity of nanofluids increased strongly as the concentration of particle is increased; it displays shear thinning and is a strong function of the level of agglomeration. The viscosity increase is significantly above of that predicted by the Einstein model even for very small concentration of nanoparticles.

Keywords

Nanofluids Thermal conductivity Viscosity Dispersion Particle size 

List of symbols

ke (W m−1 K−1)

Thermal conductivity of nanofluid

kf (W m−1 K−1)

Thermal conductivity of base fluid

kp (W m−1 K−1)

Thermal conductivity of nanoparticle

ϕ (%)

Volume percentage of nanoparticle

γ (s−1)

Shear rate

ρ (kg m−3)

Density of the fluid

μnf (Pa s)

Dynamic viscosity of nanofluid

μf (Pa s)

Dynamic viscosity of base fluid

References

  1. Abdulagatov IM, Azizov ND (2006) Experimental study of the effect of temperature, pressure and concentration on the viscosity of aqueous NaBr solutions. J Solut Chem 35:705–738. doi: 10.1021/je0604481 CrossRefGoogle Scholar
  2. Anoop KB, Kabelac S, Sundararajan T and Das SK (2009) Rheological and flow characteristics of nanofluids: influence of electroviscous effects and particle agglomeration. J Appl Phys 106. doi: 10.1063/1.3182807
  3. Bartnikos R (1994) Electrical insulating liquids, vol 3. ASTM publication 31-00209093-21Google Scholar
  4. Bruggeman DAG (1935) Berechnung verschiedener physikalischer konstanten von heterogenen substanzen, I-dielektrizitatskonstanten und leitfahigkeiten der mischkorper aus isotropen substanzen. Ann Phys (Leipzig) 24:636–679Google Scholar
  5. Buongiorno J et al (2009) A benchmark study on the thermal conductivity of nanofluids. J Appl Phys 106:094312. doi: 10.1063/1.3245330 CrossRefGoogle Scholar
  6. Chang C, Powell R (1994) Effect of particle size distribution on the rheological properties of concentrated bimodal suspensions. J Rheol 38:85–98. doi: 10.1122/1.550497 CrossRefGoogle Scholar
  7. Chen H, Ding Y, Tan C (2007a) Rheological behavior of nanofluids. New J Phys 9:367. doi: 10.1088/1367-2630/910/367 CrossRefGoogle Scholar
  8. Chen H, Ding Y, He Y, Tan C (2007b) Rheological behavior of ethylene glycol based Titania nanofluids. Chem Phys Lett 444:333–337. doi: 10.1016/j.cplett.2007.07.046 CrossRefGoogle Scholar
  9. Chen H, Yang W, Ding Y, Zhang L (2008) Heat transfer and flow behavior of aqueous suspensions of titanate nanotubes (nanofluids). Power Technol 183:63–72. doi: 10.1016/j.powtec.2007.11.014 CrossRefGoogle Scholar
  10. Choi SUS, Eastman JA (1995) Enhancing thermal conductivity of fluids with nanoparticles. ASME international mechanical engineering congress and exposition, San Francisco (Nov12–17)Google Scholar
  11. Clark R III, Taylor L (1975) Radiation heat loss in the flash method for thermal diffusivity. J Appl Phys 46:714–719. doi: 10.1063/1.321635 CrossRefGoogle Scholar
  12. Cowan R (1963) Pulse method of measuring thermal conductivity at high temperature. J Appl Phys 34:926–927. doi: 10.1063/1.1729564 CrossRefGoogle Scholar
  13. Das S, Putra N, Thiesen P, Roetzel W (2003) Temperature dependence of thermal conductivity enhancement for nanofluids. J Heat Transf 125:567–574. doi: 10.1115/1.1571080 CrossRefGoogle Scholar
  14. Das S, Choi SS, Yu W (2008) Nanofluids science and technology. Wiley, New YorkGoogle Scholar
  15. Ding Y, Chen H, Wang L, Yang CY, He Y, Yang W, Lee WP, Zhang L, Huo R (2007) Heat transfer intensification using nanofluids. KONA No. 25Google Scholar
  16. Eastman JA, Choi SUS, Li S, Yu W, Thompson LJ (2001) Anomalously increased effective thermal conductivities of ethylene glycol-based nanofluids containing copper nanoparticles. Appl Phys Lett 78:718–720. doi: 10.1063/1.1341218 CrossRefGoogle Scholar
  17. Einstein A (1911) Berichtigung zu meiner arbeit: eine neue bestimmung der molekul-dimension (correction of my work: a new determination of the molecular dimensions). Ann Phys 34:591–592CrossRefGoogle Scholar
  18. Heris SZ, Etemad SG, Esfanhany MN (2006) Experimental investigation of oxide nanofluids laminar flow convective heat transfer. Int Commun Heat Mass Transf 33:529–535. doi: 10.1016/j.icheatmasstransfer.2006.01.005 CrossRefGoogle Scholar
  19. Koski J (1981) Improved data reduction methods for laser pulse diffusivity determination with the use of minicomputer. International joint conference on thermophysical properties, GaithersburgGoogle Scholar
  20. Kwak K, Kim C (2005) Viscosity and thermal conductivity of copper oxide nanofluid dispersed in ethylene glycol. Korea Aust Rheol J 17(2):35–40Google Scholar
  21. Larson RG (2005) The rheology of dilute solutions of flexible polymers: progress and problems. J Rheol 49:1–70. doi: 10.1122/1.1835336 CrossRefGoogle Scholar
  22. Luckham PF, Ukeje MA (1999) Effect of particle size distribution on the rheology of dispersed system. J Colloid Interface Sci 220:247–356. doi: 10.1006/jcis.1999.6515 CrossRefGoogle Scholar
  23. Maxwell JC (1881) Treatise on electricity and magnetism, 2nd edn, vol 1. Clarendon Press, Oxford, p 435Google Scholar
  24. Olhero SM, Ferreira JFM (2004) Influence of particle size distribution on rheology and particle packing of silica based suspensions. Powder Technol 139:69–75. doi: 10.1016/j.powtec.2003.10.004 CrossRefGoogle Scholar
  25. Parker WJ, Jenkins RJ, Butler CP, Abbott GL (1961) A flash method of determining thermal diffusivity, heat capacity, and thermal conductivity. J Appl Phys 32:1679–1684. doi: 10.1063/1.1728417 CrossRefGoogle Scholar
  26. Prasher R, Song D, Wang J, Phelan P (2006) Measurements of nanofluid viscosity and its implication for thermal application. Appl Phys Lett 89:133108. doi: 10.1063/1.2356113 CrossRefGoogle Scholar
  27. Timofeeva EV, Roubort JL, Singh D (2009) Particle shape effect on thermophysical properties of alumina nanofluids. J Appl Phys 106:014304. doi: 10.1063/1.3155999 CrossRefGoogle Scholar
  28. Williams W, Buongiorno J, Hu L (2008) Experimental investigation of turbulent convective heat transfer and pressure loss of alumina/water and zirconia/water nanoparticle colloids (nanofluids) in horizontal tubes. J Heat Transf 130:042412-1. doi: 10.1115/1.2818775 CrossRefGoogle Scholar
  29. Xuan Y, Li Q (2000) Heat transfer enhancement of nanofluids. Int J Heat Fluid Flow 21:58–64. doi: 10.1016/S0142-727X(99)00067-3 CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2012

Authors and Affiliations

  • Yijun Yang
    • 1
  • Alparslan Oztekin
    • 1
  • Sudhakar Neti
    • 1
  • Satish Mohapatra
    • 2
  1. 1.Department of Mechanical Engineering and MechanicsLehigh UniversityBethlehemUSA
  2. 2.Dynalene Inc.WhitehallUSA

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