Heat transfer enhancement of Al2O3-H2O nanofluids flowing through a micro heat sink with complex structure

Zhai, Yuling; Xia, Guodong; Liu, Xianfei; Li, Y.F.

doi:10.1016/j.icheatmasstransfer.2015.05.025

Cited by 54 publications

(13 citation statements)

References 40 publications

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“…Experimental work reported that the thermal conductivity is enhanced by 30% for carbon nanotube nanofluids (2 vol.%) [5]; and heat transfer enhancement up to 40% has been obtained for Al2O3/water nanofluid and Al2O3/ethylene glycol nanofluid compared to the base fluid [6]. Zhai et al [7] carried out experiments to study heat transfer enhancement of Al2O3/water nanofluid through a micro heat sink with complex structure. Their results showed that higher volume fraction of nanofluids (0.1-1 vol.%) gives better comprehensive performance of heat transfer.…”

Section: Introductionmentioning

confidence: 99%

Three dimensional lattice Boltzmann simulation for mixed convection of nanofluids in the presence of magnetic field

Zhou

Yan

Xie

et al. 2017

International Communications in Heat and Mass Transfer

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In the present study, a three dimensional thermal lattice Boltzmann model was developed to investigate the flow dynamics and mixed convection heat transfer of Al2O3/water nanofluid in a cubic cavity in the presence of magnetic field. The model was first validated with previous numerical and experimental results. Satisfactory agreement was obtained. Then the effects of Rayleigh number, nanoparticle volume fraction, Hartmann number and Richardson number on nanofluid flow dynamics and heat transfer were examined. Numerical results indicate that adding nanoparticles to pure water leads to heat transfer enhancement for low Rayleigh numbers. However, this enhancement might be weakened and even reversed for high Rayleigh numbers. In addition, the results show the external applied magnetic field has an effect of suppressing the convective heat transfer in the cavity. Moreover, the results demonstrate that the Richardson number in mixed convection has significant influences on both streamlines and temperature field.

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Section: Introductionmentioning

confidence: 99%

Three dimensional lattice Boltzmann simulation for mixed convection of nanofluids in the presence of magnetic field

Zhou

Yan

Xie

et al. 2017

International Communications in Heat and Mass Transfer

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“…The performance of different geometry parameters of the microchannel with the simple and complex structure are simulated in our previous research (Zhai et al, 2015a(Zhai et al, , 2015bLiu et al, 2019). The purpose of this paper is to further explore the flow and thermal performances of serpentine microchannels with variable bend amplitudes.…”

Section: Model Descriptions 21 Computational and Geometric Configurationsmentioning

confidence: 99%

Numerical analysis of the flow and heat transfer characteristics in serpentine microchannel with variable bend amplitude

Zhang

Liu

2020

HFF

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Purpose This study aims to propose the increase of heat dissipation requirements of modern electronic equipment and the fast development of micro-scale manufacturing technologies. The heat transfer mechanism is studied in-depth, especially for its pattern of secondary flow caused by the repeated inversion of centrifugal force. Effects of η on the frictional pressure drop and average Nusselt number are studied and the performance of such microchannel heat sink with various bend amplitudes is comprehensively evaluated. These results can provide important insight into the optimal design of this novel design configuration for microelectronics cooling. Design/methodology/approach A three-dimensional model based on the finite volume approach and SIMPLEC algorithm is performed to test an innovative serpentine microchannel, which behaves differently from conventional serpentine microchannel due to the significant effect of centrifugal force inversion. Findings The effect of centrifugal force significantly influences the flow and thermal fields which are responsible for the enhancement in heat transfer coefficient. The number, size and intensity of vortices increase with increasing Re, and the vortices are reformed at every change of the geometry in a periodic fashion. The serpentine microchannel studies more effectively at larger bend amplitude. Pressure fluctuations and temperature variation are greater with increasing bend amplitude. Practical implications Several techniques have been developed to augment single-phase convective heat transfer in channels. One technique is to use a serpentine channel that enhances the heat transfer due to flow mixing and periodic interruption of thermal boundary layers. This technique has been applied to micro-heat exchangers, thermal regenerators and mini/microreactors. Social implications The optimal design of this novel design configuration for microelectronics cooling can be attained. It will become an effective cooling technology for solving the increasing of heat dissipation requirements of modern electronic equipment. Originality/value The flow and heat transfer characteristics are first presented for the circular serpentine microchannel made up of alternate U-bends without interposed straight segments. The present study first examines the effect of such centrifugal force inversion on velocity contour, pressure distribution and temperature distribution. The patterns of secondary flow along the flow passage caused by the repeated inversion of centrifugal force are further studied in depth. The effect of bend amplitude on the flow and heat transfer is explored and the performance of such microchannel heat sink has been comprehensively evaluated.

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“…For calculating the nanofluid characteristics, the density and specific heats are determined using the classical formulas derived for a two-phase mixture. 22 Basically, the density and specific heats of nanofluids are considered to change linearly with the volume fraction. That is …”

Section: Mathematical Model Of Heat Recovery Systemmentioning

confidence: 99%

“…Specifications of the existing heat recovery setup. Thermophysical properties of Al 2 O 3 nanoparticles at 20 C 22. …”

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confidence: 99%

Optimum waste heat recovery from diesel engines: Thermo-economic assessment of nanofluid-based systems using a robust evolutionary approach

Yousefi

Hooshyar

Kim

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part E:

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Nearly 30% of the input energy to a diesel engine is wasted through the exhaust gas; thus, considerable attention has been directed toward developing efficient heat recovery systems for these engines. Given the demonstrated ability of nanofluids to boost the heat transfer rate of heat exchangers, these heat transfer fluids merit consideration for use in diesel exhaust heat recovery systems. In this study, the effects of employing nanofluids on the optimum design of these systems are investigated. An existing heat diesel engine exhaust heat recovery system is modeled to work with Al 2 O 3 / water and a modified imperialist competitive algorithm is employed for the optimization. Seven variables consisting of five heat exchanger geometric characteristics together with nanoparticle volume fraction and coolant mass flow rate are considered as design variables. The heat exchanger cost and charging rate of the storage tank are optimization objectives, while the greenhouse gas savings of the heat recovery system are assessed for measuring the environmental impact of the energy recovery. The results indicate that the proposed approach can overcome the challenge of finding the near-optimal design of this complex system and using nanofluids enhances the performance of the heat recovery heat exchanger.

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Heat transfer enhancement of Al2O3-H2O nanofluids flowing through a micro heat sink with complex structure

Cited by 54 publications

References 40 publications

Three dimensional lattice Boltzmann simulation for mixed convection of nanofluids in the presence of magnetic field

Three dimensional lattice Boltzmann simulation for mixed convection of nanofluids in the presence of magnetic field

Numerical analysis of the flow and heat transfer characteristics in serpentine microchannel with variable bend amplitude

Optimum waste heat recovery from diesel engines: Thermo-economic assessment of nanofluid-based systems using a robust evolutionary approach

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