Natural convection in nanofluids: Are the thermophoresis and Brownian motion effects significant in nanofluid heat transfer enhancement?

Haddad, Zoubida; Abu‐Nada, Eiyad; Öztop, Hakan F.; Mataoui, Amina

doi:10.1016/j.ijthermalsci.2012.01.016

Cited by 242 publications

(123 citation statements)

References 26 publications

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“…The increase was possibly related to the Brownian motion of nanoparticle [23,30]. It was reported that the Brownian motion effect of nanoparticles on thermal conductivity was more pronounced at low mass fraction of nanoparticles [31]. However, in this case, the increase in thermal conductivity was rather small compared to the one containing inorganic or oxide nanoparticles [21,32,33].…”

Section: Ftir Characterizations Of Dbsa-pani Nanoparticlesmentioning

confidence: 81%

Thermal Conductivity and Specific Heat Capacity of Dodecylbenzenesulfonic Acid-Doped Polyaniline Particles—Water Based Nanofluid

2015

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Nanofluid has attracted great attention due to its superior thermal properties. In this study, chemical oxidative polymerization of aniline was carried out in the presence of dodecylbenzenesulfonic acid (DBSA) as a dopant. Particles of DBSA-doped polyaniline (DBSA-doped PANI) with the size range of 15 to 50 nm were obtained, as indicated by transmission electron microscope (TEM). Results of ultra violet-visible (UV-Vis) absorption and Fourier transform infrared (FTIR) spectroscopies as well as thermogravimetric analysis showed that PANI nanoparticles were doped with DBSA molecules. The doping level found was 36.8%, as calculated from elemental analysis data. Thermal conductivity of water was enhanced by 5.4% when dispersed with 1.0 wt% of DBSA-PANI nanoparticles. Specific heat capacity of water-based nanofluids decreased with increasing amount of DBSA-PANI nanoparticles.

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Section: Ftir Characterizations Of Dbsa-pani Nanoparticlesmentioning

confidence: 81%

Thermal Conductivity and Specific Heat Capacity of Dodecylbenzenesulfonic Acid-Doped Polyaniline Particles—Water Based Nanofluid

2015

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“…This has implications in medical applications, power generation, micro-manufacturing, thermal therapy for cancer treatment, chemical and metallurgical sectors, microelectronics, aerospace and manufacturing. 12 Representative works on convective boundary layer flow and application of nanofluids were conducted by Buongiorno, 13 Das et al, 14 Kakaç and Pramuanjaroenkij, 15 Saidur et al 16 and Wen et al 17 Further studies have been communicated by Mahian et al, 18 Nield and Bejan, 19 Haddad et al, 20 Sheremet and Pop 21 and many others. There are two types of model for nanofluids which have been commonly used by the researchers, namely Buongiorno's model 13 and the Tiwari-Das model.…”

Section: Introductionmentioning

confidence: 99%

Nanofluid slip flow over a stretching cylinder with Schmidt and Péclet number effects

et al. 2016

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A mathematical model is presented for three-dimensional unsteady boundary layer slip flow of Newtonian nanofluids containing gyrotactic microorganisms over a stretching cylinder. Both hydrodynamic and thermal slips are included. By applying suitable similarity transformations, the governing equations are transformed into a set of nonlinear ordinary differential equations with appropriate boundary conditions. The transformed nonlinear ordinary differential boundary value problem is then solved using the Runge-Kutta-Fehlberg fourth-fifth order numerical method in Maple 18 symbolic software. The effects of the controlling parameters on the dimensionless velocity, temperature, nanoparticle volume fractions and microorganism motile density functions have been illustrated graphically. Comparisons of the present paper with the existing published results indicate good agreement and supports the validity and the accuracy of our numerical computations. Increasing bioconvection Schmidt number is observed to depress motile micro-organism density function. Increasing thermal slip parameter leads to a decrease in temperature. Thermal slip also exerts a strong influence on nano-particle concentration. The flow is accelerated with positive unsteadiness parameter (accelerating cylinder) and temperature and micro-organism density function are also increased. However nano-particle concentration is reduced with positive unsteadiness parameter. Increasing hydrodynamic slip is observed to boost temperatures and micro-organism density whereas it decelerates the flow and reduces nano-particle concentrations. The study is relevant to nano-biopolymer manufacturing processes.

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“…A linear analysis of the Rayleigh-Bénard instability for a nanofluid is performed by Yadav et al [11]. Haddad et al [12] reported that the thermophoresis and Brownian motion are significant in the thermal enhancement of the natural convection in a nanofluid layer. Recently, Gupta et al [13] investigated the thermosolutal convection in a horizontal nanofluid layer heated from below.…”

Section: Introductionmentioning

confidence: 99%

Effect of Internal Heat Source on the Onset of Double-Diffusive Convection in a Rotating Nanofluid Layer with Feedback Control Strategy

Khalid

Mokhtar

Hashim

et al. 2017

Advances in Mathematical Physics

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A linear stability analysis has been carried out to examine the effect of internal heat source on the onset of Rayleigh-Bénard convection in a rotating nanofluid layer with double diffusive coefficients, namely, Soret and Dufour, in the presence of feedback control. The system is heated from below and the model used for the nanofluid layer incorporates the effects of thermophoresis and Brownian motion. Three types of bounding systems of the model have been considered which are as follows: both the lower and upper bounding surfaces are free, the lower is rigid and the upper is free, and both of them are rigid. The eigenvalue equations of the perturbed state were obtained from a normal mode analysis and solved using the Galerkin method. It is found that the effect of internal heat source and Soret parameter destabilizes the nanofluid layer system while increasing the Coriolis force, feedback control, and Dufour parameter helps to postpone the onset of convection. Elevating the modified density ratio hastens the instability in the system and there is no significant effect of modified particle density in a nanofluid system.

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Natural convection in nanofluids: Are the thermophoresis and Brownian motion effects significant in nanofluid heat transfer enhancement?

Cited by 242 publications

References 26 publications

Thermal Conductivity and Specific Heat Capacity of Dodecylbenzenesulfonic Acid-Doped Polyaniline Particles—Water Based Nanofluid

Thermal Conductivity and Specific Heat Capacity of Dodecylbenzenesulfonic Acid-Doped Polyaniline Particles—Water Based Nanofluid

Nanofluid slip flow over a stretching cylinder with Schmidt and Péclet number effects

Effect of Internal Heat Source on the Onset of Double-Diffusive Convection in a Rotating Nanofluid Layer with Feedback Control Strategy

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