Does mathematics contribute to the nanofluid debate?

Myers, T.G.; Ribera, Helena; Cregan, Vincent

doi:10.1016/j.ijheatmasstransfer.2017.03.118

Cited by 83 publications

(37 citation statements)

References 59 publications

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“…When they did this, they found that the nanofluid performance was actually worse than water. The errors caused by comparison using non-dimensional parameters is discussed in greater detail in Myers et al [23]: as stated above it does not make sense to compare Reynolds numbers which are scaled with concentration dependent properties, neither Nusselt numbers which are scaled with thermal conductivity. The authors continue with a critique of mathematical studies highlighting common errors, such as incorrect governing equations and parameter values that lead to the enhancements predicted by these theoretical studies.…”

Section: Introductionmentioning

confidence: 99%

A practical evaluation of the performance of Al2O3-water, TiO2-water and CuO-water nanofluids for convective cooling

Alkasmoul

Al-Asadi

Myers

et al. 2018

International Journal of Heat and Mass Transfer

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The convective heat transfer, pressure drop and required pumping power for the turbulent flow of Al2O3water, TiO2-water and CuO-water nanofluids in a heated, horizontal tube with a constant heat flux are investigated experimentally. Results show that presenting nanofluid performance by the popular approach of plotting Nusselt number versus Reynolds number is misleading and can create the impression that nanofluids enhance heat transfer efficiency. This approach is shown to be problematic since both Nusselt number and Reynolds number are functions of nanofluid concentration. When results are presented in terms of actual heat transfer coefficient or tube temperature versus flow rate or pressure drop, adding nanoparticles to the water is shown to degrade heat transfer for all the nanofluids and under all conditions considered. Replacing water with nanofluid at the same flow rate reduces the convective heat transfer rate by reducing the operating Reynolds number of the system. Achieving a target temperature under a given heat load is shown to require significantly higher flow rates and pumping power when using nanofluids compared to water, and hence none of the nanofluids are found to offer any practical benefits. Declarations of interest: noneNomenclature A Inside surface area of the test section tube (m 2 ) Cp Specific heat (J/kg.K) Pr Prandtl number V Average fluid velocity (m/s) Greek letters  Volume fraction of nanofluids Ratio between the nanolayer thickness surrounding the nanoparticle and the nanoparticle radius Kinematic viscosity (m 2 /s) Density (kg/m 3 ) µ Dynamic viscosity (Pa s)

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Section: Introductionmentioning

confidence: 99%

A practical evaluation of the performance of Al2O3-water, TiO2-water and CuO-water nanofluids for convective cooling

Alkasmoul

Al-Asadi

Myers

et al. 2018

International Journal of Heat and Mass Transfer

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“…9 , Sheikholeslami and Ganji 10 , Myers et al . 11 , as well as in the research articles by Mehryan et al . 12 , Mohebbi et al .…”

Section: Introductionmentioning

confidence: 83%

A novel hybridity model for TiO2-CuO/water hybrid nanofluid flow over a static/moving wedge or corner

Dinarvand

Rostami

Pop

2019

Sci Rep

103

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In this study, we are going to investigate semi-analytically the steady laminar incompressible two-dimensional boundary layer flow of a TiO2-CuO/water hybrid nanofluid over a static/moving wedge or corner that is called Falkner-Skan problem. A novel mass-based approach to one-phase hybrid nanofluid model that suggests both first and second nanoparticles as well as base fluid masses as the vital inputs to obtain the effective thermophysical properties of our hybrid nanofluid, has been presented. Other governing parameters are moving wedge/corner parameter (λ), Falkner-Skan power law parameter (m), shape factor parameter (n) and Prandtl number (Pr). The governing partial differential equations become dimensionless with help of similarity transformation method, so that we can solve them numerically using bvp4c built-in function by MATLAB. It is worthwhile to notice that, validation results exhibit an excellent agreement with already existing reports. Besides, it is shown that both hydrodynamic and thermal boundary layer thicknesses decrease with the second nanoparticle mass as well as Falkner-Skan power law parameter. Further, we understand our hybrid nanofluid has better thermal performance relative to its mono-nanofluid and base fluid, respectively. Moreover, a comparison between various values of nanoparticle shape factor and their effect on local heat transfer rate is presented. It is proven that the platelet shape of both particles (n1 = n2 = 5.7) leads to higher local Nusselt number in comparison with other shapes including sphere, brick and cylinder. Consequently, this algorithm can be applied to analyze the thermal performance of hybrid nanofluids in other different researches.

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“…The study of the impacts of non-uniform wall temperature variations in trapeziums has found various practical applications in solar collectors, heat exchangers, heat pipes, and so on. Many useful references concerning nanofluids can be found in interesting books and papers [23][24][25][26][27][28][29][30][31][32][33][34][35].…”

Section: Introductionmentioning

confidence: 99%

Impacts of Non-Uniform Border Temperature Variations on Time-Dependent Nanofluid Free Convection within a Trapezium: Buongiorno’s Nanofluid Model

Revnic¹,

Ghalambaz

Groşan

et al. 2019

Energies

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The present study develops the influence of inclined border temperature variations on the isotherms, streamlines, and isoconcentrations for unsteady free convection in a trapezoidal region filled with the water-based nanofluid. The considered mathematical nanofluid approach was formulated based on the Buongiorno’s model. The set of governing partial differential equations formulated using non-dimensional primitive variables such as velocity, pressure, temperature, and nanoparticles concentration volume fraction was solved numerically using the finite element method for various magnitudes of control characteristics. It was revealed that control characteristics affected the liquid circulation and energy transport coefficients. The Nusselt number is a growing function of wave number, amplitude, and the Rayleigh number.

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Does mathematics contribute to the nanofluid debate?

Cited by 83 publications

References 59 publications

A practical evaluation of the performance of Al2O3-water, TiO2-water and CuO-water nanofluids for convective cooling

A practical evaluation of the performance of Al2O3-water, TiO2-water and CuO-water nanofluids for convective cooling

A novel hybridity model for TiO2-CuO/water hybrid nanofluid flow over a static/moving wedge or corner

Impacts of Non-Uniform Border Temperature Variations on Time-Dependent Nanofluid Free Convection within a Trapezium: Buongiorno’s Nanofluid Model

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