Heat Transfer Enhancement of TiO2/Water Nanofluids Flowing Inside a Square Minichannel with a Microfin Structure: A Numerical Investigation

Kristiawan, Budi; Wijayanta, Agung Tri; Enoki, Koji; Miyazaki, Takahiko; Aziz, Muhammad

doi:10.3390/en12163041

Cited by 35 publications

(19 citation statements)

References 54 publications

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“…The results show that adding 10% copper nanoparticles to the water/glycol mixture can enhance the heat transfer of the medium by about 30%. Kristiawan et al [32] studied two passively enhanced heat transfer technologies combining a microchannel structure and a nanofluid by measuring Nusselt number, friction coefficient and heat transfer performance. It has been proven that, compared with water flowing in a square microchannel, using nanofluids with a volume fraction of 0.01% can increase the heat transfer efficiency of the microchannel.…”

Section: Introductionmentioning

confidence: 99%

Performance and Exergy Transfer Analysis of Heat Exchangers with Graphene Nanofluids in Seawater Source Marine Heat Pump System

Wang

Han

et al. 2020

Energies

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A marine seawater source heat pump is based on the relatively stable temperature of seawater, and uses it as the system’s cold and heat source to provide the ship with the necessary cold and heat energy. This technology is one of the important solutions to reduce ship energy consumption. Therefore, in this paper, the heat exchanger in the CO2 heat pump system with graphene nano-fluid refrigerant is experimentally studied, and the influence of related factors on its heat transfer enhancement performance is analyzed. First, the paper describes the transformation of the heat pump system experimental bench, the preparation of six different mass concentrations (0~1 wt.%) of graphene nanofluid and its thermophysical properties. Secondly, this paper defines graphene nanofluids as beneficiary fluids, the heat exchanger gains cold fluid heat exergy increase, and the consumption of hot fluid heat is heat exergy decrease. Based on the heat transfer efficiency and exergy efficiency of the heat exchanger, an exergy transfer model was established for a seawater source of tube heat exchanger. Finally, the article carried out a test of enhanced heat transfer of heat exchangers with different concentrations of graphene nanofluid refrigerants under simulated seawater constant temperature conditions and analyzed the test results using energy and an exergy transfer model. The results show that the enhanced heat transfer effect brought by the low concentration (0~0.1 wt.%) of graphene nanofluid is greater than the effect of its viscosity on the performance and has a good exergy transfer effectiveness. When the concentration of graphene nanofluid is too high, the resistance caused by the increase in viscosity will exceed the enhanced heat transfer gain brought by the nanofluid, which results in a significant decrease in the exergy transfer effectiveness.

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Section: Introductionmentioning

confidence: 99%

Performance and Exergy Transfer Analysis of Heat Exchangers with Graphene Nanofluids in Seawater Source Marine Heat Pump System

Wang

Han

et al. 2020

Energies

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“…That is, there are the advantages that a flow can be created only by a magnetic force without direct contact with the fluid, and that control is possible with a relatively simple configuration. In addition, it was confirmed that nanofluids have superior thermal performance compared to general fluid, due to the properties of the particles [4,5].…”

Section: Introductionmentioning

confidence: 89%

Effect of Magnetic Nanofluids on the Performance of a Fin-Tube Heat Exchanger

Choi

Kim

2021

Applied Sciences

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As electrical devices become smaller, it is essential to maintain operating temperature for safety and durability. Therefore, there are efforts to improve heat transfer performance under various conditions, such as using extended surfaces and nanofluids. Among them, cooling methods using ferrofluid are drawing the attention of many researchers. This fluid can control the movement of the fluid in magnetic fields. In this study, the heat transfer performance of a fin-tube heat exchanger, using ferrofluid as a coolant, was analyzed when external magnetic fields were applied. Permanent magnets were placed outside the heat exchanger. When the magnetic fields were applied, a change in the thermal boundary layer was observed. It also formed vortexes, which affected the formation of flow patterns. The vortex causes energy exchanges in the flow field, activating thermal diffusion and improving heat transfer. A numerical analysis was used to observe the cooling performance of heat exchangers, as the strength and number of the external magnetic fields were varying. VGs (vortex generators) were also installed to create vortex fields. A convective heat transfer coefficient was calculated to determine the heat transfer rate. In addition, the comparative analysis was performed with graphical results using contours of temperature and velocity.

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“…Other research has also shown that the overall composition of nanoparticles in the base fluid improves the overall heat transfer coefficient [30][31][32][33].…”

Section: Introductionmentioning

confidence: 94%

Evaluation and Improvement of PCM Melting in Double Tube Heat Exchangers Using Different Combinations of Nanoparticles and PCM (The Case of Renewable Energy Systems)

2021

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In this work, the melting process of phase change material (PCM) in double tube heat exchangers was investigated and evaluated through the use of different combinations (1, 2, 3% Nano-Enhanced PCM and 1, 3, 5% Nano-HTF) of GQD, as well as SWCNT nanoparticles and PCM (RT82). In this study, the effect of three different methods, namely the dispersion of nanoparticles in PCM (nano-enhanced PCM), the dispersion of nanoparticles in HTF (nano-HTF), and the simultaneous dispersion of nanoparticles in PCM and HTF (nano-enhanced PCM, nano-HTF) concerning the nanoparticles participation in the thermal energy storage system in a double tube heat exchanger was evaluated. Other effective factors, such as the inlet fluid temperature, different Reynolds numbers, fin as well as new parameter of pipe, and fin thickness were also evaluated. The results showed that the highest effect of different parameters on the PCM melting process was related to the 1% nano-HTF and 3% nano-enhanced PCM nanoparticles of SWCNT, which decreased the PCM melting rate by about 39%. The evaluation of the effect of pipe and fan thickness also showed that the melting rate improved by 31% through reducing the thickness of the HTF fin and pipe. In general, the current study followed two purposes first, to examine three methods of the dispersion of nanoparticles in the thermal energy storage system; second, to reduce the thickness of the tube and fin. Findings of the study yielded positive results.

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Heat Transfer Enhancement of TiO2/Water Nanofluids Flowing Inside a Square Minichannel with a Microfin Structure: A Numerical Investigation

Cited by 35 publications

References 54 publications

Performance and Exergy Transfer Analysis of Heat Exchangers with Graphene Nanofluids in Seawater Source Marine Heat Pump System

Performance and Exergy Transfer Analysis of Heat Exchangers with Graphene Nanofluids in Seawater Source Marine Heat Pump System

Effect of Magnetic Nanofluids on the Performance of a Fin-Tube Heat Exchanger

Evaluation and Improvement of PCM Melting in Double Tube Heat Exchangers Using Different Combinations of Nanoparticles and PCM (The Case of Renewable Energy Systems)

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