Numerical modeling of nanofluids

ByDr. *********************

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Introduction

base fluid +nano-sized particles (1–100 nm) nanofluid

ruling conditions of experiments {combination { base fluid

suspended particles { types¿concentration

geometry of the problem

flow regime { laminar flowturbulent flow

convectionmechanism {force convectionfree convectionmix convection

Hence we must use real conditions in our numerical simulations.

IntroductionProperties

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Governing equations

Lattice Boltzmann method Conclusions

Nanofluid properties in modelling

Essential properties  ¿ solve

governing conservation equations  {thermal conductivityviscositydensity

heat capacitance

IntroductionProperties

Governing equations

Lattice Boltzmann method Conclusions

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viscosity

Relation between nanofluid viscosity and basefluid viscosity

Viscosity models{BrinkmanNamburaMaiga

Arefmanesh and Mahmoodi 2011

Influence of Richardson number and concentration of particles

IntroductionProperties

Governing equations

Lattice Boltzmann method Conclusions

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Thermal conductivity

Relation between nanofluid thermal conductivity and particle volume fraction

Thermal conductivity models{classicmodels { MaxwelmodelHamilton∧crosser (HC )model

Brownianmotion dependent modelstemperature dependent models

IntroductionProperties

Governing equations

Lattice Boltzmann method Conclusions

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Density and heat capacity

Pak and Cho correlation:

IntroductionProperties

Governing equations

Lattice Boltzmann method Conclusions

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Governing equations

modelling of nanofluids { two − phasesingle − phase

Introduction Properties Governing equations

Lattice Boltzmann method Conclusions

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Single-phase modeling

Work of Ding and Wen 2005

Authors Year Geometry Explanation Observation

Lin and Violi

2010non-uniform

particle diameter

Enhancement in heat transfer with increase of

minimum diameter to maximum diameter ratio

Vajjha et al.

2010 Complex geometry

Augmentation in heat transfer and higher

pumping power relative to basefluid

Introduction Properties Governing equations

Lattice Boltzmann method Conclusions

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Two-phase modeling

The slip velocity between particles and the fluid might not be zero.

Assumptions { StrongcouplingSeparate behavior

Fluid followed by particles

Authors Year Geometry Explanation Observation

Behzadmehr et al.

2007 Forced convection of a nanofluid in a tube with

uniform heat flux

Mixture model

Kalte et al. 2011 Eulerian model

More accurate results compared with homogenous models

Lotfi et al. 2010 horizontal tube Comparison Mixture modelEulerian model

Single phase model

Introduction Properties Governing equations

Lattice Boltzmann method Conclusions

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Lattice Boltzmann method

Interface between microscopic and macroscopic point of view (Mesoscopic).Authors Year Geometry Explanation Observation

Kefayati et al. 2011

Lattice Boltzmann BGK method

Good agreement with previous works

Lai and Yang 2011Lattice Boltzmann BGK

methodIn high Reynolds

number we must useSmall size mesh to

stability

Nabavi et al. 2011 Multi relaxation time More stability

Introduction Properties Governing equations Lattice Boltzmann

method

Conclusions

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Conclusions

Nanofluid modeling { Single− phasemodelTwo− phase model

Unconventional methods (LBM )

Introduction PropertiesGoverning equations

Lattice Boltzmann method Conclusions

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New and future works about nano fluids

Non-Newtonian nanofluids

Hybrid nanofluids

Shafiee Neistanak university of Calgary

Suresh research group

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Thanks for your attention.

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