Heat transfer enhancement using Al 2 O 3 -EG/W(60/40 vol%) in multiple-pipe heat exchanger

Rahimi, Alireza; Amiri, Ali; Kasaeipoor, Abbas; Malekshah, Emad Hasani

doi:10.1016/j.molliq.2018.04.008

Cited by 28 publications

(17 citation statements)

References 45 publications

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“…As it was mentioned at the beginning of the article in the introduction section, there are a large number of heat transfer systems based on the concept of free movement and fluid motion based on temperature gradient [1]. Which by applying nanofluids, the problems of low heat transfer coefficient of conventional fluids were largely solved [3]. However, it should be noted that temperature gradient is not the only parameter that induces motion, or alters fluid motion, and changes in heat and mass transfer patterns, but also other influential parameters, including concentration gradient, and applying a magnetic field can be mentioned [14,17,19,27].In this article, it has been tried to deal with the interaction of temperature gradient, the concentration, size of the magnetic field, and the type of nanofluid.…”

Section: Resultsmentioning

confidence: 99%

“…The problem with conventional convective systems is the low thermal conductivity of the working fluids [2]. An advanced technique to improve heat transfer efficiency is by using dispersed solid nanoparticles (smaller than 100 nm) in a working fluid which is known as nanofluid [3]. The implementation of this technique has been reported extensively over the past years to enhance heat transfer rate in industrial applications such as double pipe heat exchangers and channels, and the results have shown success in achieving this goal [4,5].…”

Section: Introductionmentioning

confidence: 99%

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Lattice Boltzmann simulation of magneto-hydrodynamic double-diffusive natural convection in an enclosure with internal heat and solute source using nanofluids

2020

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Magneto-hydrodynamic double-diffusive natural convection in a cavity is numerically investigated in the present work. Al 2 O 3 , Cu, and Ag based nanofluids in a square cavity with a thermal and solute source in the center, and uniform magnetic field are considered. The Patel model is employed to estimate the thermal conductivity of applied nanofluids, and the numerical calculation is based on the implementation of the lattice Boltzmann method and utilizing the standard D 2 Q 9 model to study the heat transfer, and also species concentration. A parametric study is carried out to observe the influence of the type, the volume fraction of nanoparticle ( = 0 − 5% ), Rayleigh ( Ra = 10 4 − 10 5 − 10 6 ) , Lewis (0.1 − 2 − 10) , and Hartmann number (10 − 20 − 100) on average Nusselt and Sherwood numbers, flow fields, temperature, and concentration distribution. The results show that an augment in nanoparticle volume fraction and Rayleigh number increased the average Nusselt and Sherwood numbers. Lewis number showed a significant impact on mass transfer rate. However, it did not affect the heat transfer rate remarkably. Applying a magnetic field caused a reduction in flow circulation which resulted in a decline in heat and mass transfer. A comparison of the simulation outcome with the available data shows that the generated code perfectly captures the fluid flow behavior and heat transfer process as a function of the affecting parameters. KeywordsMHD double-diffusive natural convection • Square enclosure • Nanofluids • Lattice Boltzmann method List of symbols Ar Aspect ratio B The magnitude of the magnetic field, T c Lattice speed, m∕s c i Discrete particle speed, m∕s c s Sound velocity, m∕s C Concentration C p Specific heat, Jkg −1 K D Mass diffusivity, m 2 ∕s f , g, h Discrete distribution function F External force

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Lattice Boltzmann simulation of magneto-hydrodynamic double-diffusive natural convection in an enclosure with internal heat and solute source using nanofluids

2020

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“…Heat transfer efficiency, geometry miniaturization, optimization, and hydraulic improvement are some of the hot-debated topics considered by researchers aiming at improving the overall performance of the heat exchanger units, mainly when nanofluids are utilized as the working fluid [25]. For example, Rahimi et al [26] numerically examined Al 2 O 3 /water-EG nanofluid turbulent flow within a D-shaped heat exchanger. Nanofluid with 1 vol.% concentration showed the highest performance and the most significant heat transfer coefficient and friction factor.…”

Section: Introductionmentioning

confidence: 99%

Combination Effect of Baffle Arrangement and Hybrid Nanofluid on Thermal Performance of a Shell and Tube Heat Exchanger Using 3-D Homogeneous Mixture Model

Alazwari

Safaei

2021

Mathematics

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In this study, thermal performance and flow characteristics of a shell and tube heat exchanger equipped with various baffle angles were studied. The heat exchanger was operated with distilled water, and a hybrid nanofluid at three concentrations of 0.04% and 0.10% of GNP-Ag/water within Reynolds numbers ranged between 10,000 and 20,000. The thermophysical properties of nanofluid varied with temperature and nanoparticles’ concentration. The baffle angles were set at 45°, 90°, 135°, and 180°. Results showed that the calculated Nusselt number (Nu) could be improved by adding nanoparticles to the distilled water or increasing the fluid’s Reynolds number. At a low Re number, the Nu corresponding to baffle angle of 135° was very close to that recorded for the angle of 180°. At Re = 20,000, the Nu number was the highest (by 35% compared to the reference case), belonging to a baffle angle of 135°. Additionally, results related to friction factor and pressure drop showed that more locations with fluid blocking were observed by increasing the baffle angle, resulting in increased pressure drop value and friction. Finally, the temperature streamlines counter showed that the best baffle angle could be 135° in which maximum heat removal and the best thermal performance can be observed.

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“…Nusselt number correlations for Al 2 O 3 nanofluids flowing through an inclined copper tube were postulated (5 × 10 5 < Ra < 9.6 × 10 5 , 350 < Re < 900, and 0 <φ < 4.0%). Rahimi et al 27 studied Al 2 O 3 + EG (60%)/W (40%) fluids in multiple-pipe-heat-exchanger with respect to the HTP. They found that Rayleigh number improves the average Nusselt number.…”

Section: Introductionmentioning

confidence: 99%

Performance evaluation of Al₂O₃nanofluid as an enhanced heat transfer fluid

Kong

Lee

2020

Advances in Mechanical Engineering

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Thermal performance of Al2O3 nanoparticles dispersed in water was evaluated experimentally in a fully instrumented circular tube under turbulent flow conditions. Thermophysical properties of Al2O3 nanofluids at three different volumetric concentrations (0.38%, 0.81%, and 1.30%) were determined as a function of temperature. Pressure drop and heat transfer experiments were carried out at different volumetric concentrations and inlet fluid temperatures (10°C–30°C). The overall performance of the Al2O3 nanofluids was evaluated by considering both their hydraulic and heat transfer characteristics. The experimental results showed that the use of Al2O3 nanofluids increases the pressure drop by up to about 13% due to the greater viscosity. In addition, the heat transfer coefficient of nanofluids increased with the volumetric concentration by up to approximately 19% induced by the enhanced thermal conductivity. Furthermore, the experimental results indicated that the nanofluid with a volume fraction of 0.81% at the highest inlet fluid temperature increases the overall performance by up to around 8% and performs better than the other volume fractions. Enhancement in the overall performance increases with increasing inlet fluid temperature because of both the enhanced effective thermal conductivity and the decreased viscosity, which increases the energy exchange and decreases the pressure loss, respectively.

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Heat transfer enhancement using Al 2 O 3 -EG/W(60/40 vol%) in multiple-pipe heat exchanger

Cited by 28 publications

References 45 publications

Lattice Boltzmann simulation of magneto-hydrodynamic double-diffusive natural convection in an enclosure with internal heat and solute source using nanofluids

Lattice Boltzmann simulation of magneto-hydrodynamic double-diffusive natural convection in an enclosure with internal heat and solute source using nanofluids

Combination Effect of Baffle Arrangement and Hybrid Nanofluid on Thermal Performance of a Shell and Tube Heat Exchanger Using 3-D Homogeneous Mixture Model

Performance evaluation of Al₂O₃nanofluid as an enhanced heat transfer fluid

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Heat transfer enhancement using Al 2 O 3 -EG/W(60/40 vol%) in multiple-pipe heat exchanger

Cited by 28 publications

References 45 publications

Lattice Boltzmann simulation of magneto-hydrodynamic double-diffusive natural convection in an enclosure with internal heat and solute source using nanofluids

Lattice Boltzmann simulation of magneto-hydrodynamic double-diffusive natural convection in an enclosure with internal heat and solute source using nanofluids

Combination Effect of Baffle Arrangement and Hybrid Nanofluid on Thermal Performance of a Shell and Tube Heat Exchanger Using 3-D Homogeneous Mixture Model

Performance evaluation of Al2O3nanofluid as an enhanced heat transfer fluid

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Performance evaluation of Al₂O₃nanofluid as an enhanced heat transfer fluid