Heat transfer enhancement of nanofluid flow at the entry region of microtubes

Ma, Hao; He, Boshu; Su, Liangbin; He, Di

doi:10.1016/j.ijthermalsci.2022.107944

Cited by 30 publications

(4 citation statements)

References 75 publications

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“…The papers reported above [14][15][16][17][18][19][20] show that the application of nanofluids for increasing heat transfer is widely investigated in different heat exchanger applications, and nanofluid has allowed for the construction of smaller heat exchangers, because lower mass flow rates are required, as mentioned above.…”

Section: Introductionmentioning

confidence: 97%

“…It has been demonstrated that introducing oil as a base fluid enhances the thermal performance of the components. Ma et al [15] carried out a numerical study on laminar flow and convection at the entry region of microchannels with heat flux and temperature boundary conditions. The results showed the dependence of the apparent friction factor from the Reynolds number and the influence of the axial heat transfer on the Nusselt number, taking into account the entry region.…”

Section: Introductionmentioning

confidence: 99%

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Preliminary Results of Heat Transfer and Pressure Drop Measurements on Al2O3/H2O Nanofluids through a Lattice Channel

2023

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A nanofluid is composed of a base fluid with a suspension of nanoparticles that improve the base fluid’s thermophysical properties. In this work, the authors have conducted experimental tests on an alumina-based nanofluid (Al2O3/H2O) moving inside a 3D-printed lattice channel. The unit cell’s lattice shape can be considered a double X or a double pyramidal truss with a common vertex. The test channel is 80 mm long and has a cross-sectional area, without an internal lattice with that has the dimensions H × W, with H = 5 mm and W = 15 mm. A nanofluid and a lattice duct can represent a good compound technique for enhancing heat transfer. The channel is heated by an electrical resistance wound onto its outer surface. The heat transfer rate absorbed by the nanofluid, the convective heat transfer coefficients, and the pressure drops are evaluated. The experimental tests are carried out at various volumetric contents of nanoparticles (φ = 1.00%, φ = 1.50% and φ = 2.05%) and at various volumetric flow rates (from 0.2 L/min to 2 L/min). The preliminary results show that in the range between 0.5 L/min ÷ 2.0 L/min, the values of convective heat transfer coefficients are greater than those of pure water (φ = 0) for all concentrations of Al2O3; thus, the nanofluid absorbed a higher thermal power than the water, with an average increase of 6%, 9%, and 14% for 1.00%, 1.50% and 2.05% volume concentrations, respectively. The pressure drops are not very different from those of water; therefore, the use of nanofluids also increased the cooling efficiency of the system.

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Section: Introductionmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Preliminary Results of Heat Transfer and Pressure Drop Measurements on Al2O3/H2O Nanofluids through a Lattice Channel

2023

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“…In the last century, the enhancement of heat transfer has become the most requested and interesting topic for engineers and scientists in many areas. Rapid technological advancement proves that using nanofluids is one of the methods to enhance heat transfer due to their specific characteristics and properties compared to pure fluids [1][2][3]. Abed et al [4] investigated heat transfer within a trapezoidal enclosure containing Ag-water nanofluid by using the finite element technique.…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of natural convection heat transfer using TiO₂/Al₂O₃-water nanofluids

Oulahou,

Elguennouni,

Hssikou

et al. 2024

FME Transactions

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Recently, nanofluids have been used as an alternative in several industries to improve the heat transfer process. This paper focuses on the numerical modeling of the performance of the natural convection process through TiO₂/Al₂O₃-water nanofluids in a square cavity containing a heated block. The lattice Boltzmann method is used in this study to present the nanofluid heat transfer enhancement. Results are presented in terms of streamlines, isothermal contours, and Nusselt number profiles. The findings demonstrate that by raising the Rayleigh number and solid nanoparticle concentration, the average Nusselt number increases, and they reveal that the heated block enormously affects the flow structure and heat transfer. It is also demonstrated that the type of nanoparticles significantly impacts the natural convection heat transfer.

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“…The passive technique is generally preferred because this method does not need any external energy to enhance heat transfer. The objective can be achieved by inserting twinned coil/twisted tape into the tube [2][3][4][5][6], adding nanoparticles to the base fluid [7][8][9][10][11], and modifying the tube structure of the heat exchanger, such as with a corrugated tube [12][13][14], a micro-fin tube [15][16], a flattened tube [17][18], a twisted flattened tube [19], or a twisted oval tube [20][21]. These reports concluded that modifying the tube shape to enhance the heat transfer of the internal flow was an attractive approach.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study on Convective Heat Transfer and Pressure Drop Characteristics of an Alternating Cross-Section Flattened Tube with Different Twist Angle

Warnropru¹,

Kaew-On²,

Chimres³

2023

ASEAN Sci Tech Rept

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In this research, the heat transfer coefficient (HTC) and pressure drop of alternating cross-section flattened (ACF) tubes were investigated experimentally and compared with the same parameters of a circular tube. Three different ACF tubes were fabricated from circular copper tubing with an internal diameter of 4.5 mm, a thickness of 1 mm, and a length of 400 mm. The twist angles were 30, 45, and 90°. The experimental ranges covered a mass flux of 729–1,434 kg/m2s and a heat flux of 12–30 kW/m2. The results showed that the HTC and pressure drop increased with mass flux. The HTC decreased with increments of heat flux, but the pressure drop did not change. The HTC and pressure drop of the ACF tubes were higher than those of the circular tube. The ACF tube with 90° twist angles produced the highest HTC, and the thermal performance of that tube was about 27% better than the thermal performance of the circular tube.

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Heat transfer enhancement of nanofluid flow at the entry region of microtubes

Cited by 30 publications

References 75 publications

Preliminary Results of Heat Transfer and Pressure Drop Measurements on Al2O3/H2O Nanofluids through a Lattice Channel

Preliminary Results of Heat Transfer and Pressure Drop Measurements on Al2O3/H2O Nanofluids through a Lattice Channel

Numerical investigation of natural convection heat transfer using TiO₂/Al₂O₃-water nanofluids

Experimental Study on Convective Heat Transfer and Pressure Drop Characteristics of an Alternating Cross-Section Flattened Tube with Different Twist Angle

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