scholarly journals Improved thermal conductivity and stability of Na2SO4⋅10H2O PCMs system by incorporation of Al/C hybrid nanoparticles

2021 ◽  
Vol 12 ◽  
pp. 982-988
Author(s):  
Xin Liu ◽  
Jian Tie ◽  
Zhenya Wang ◽  
Yuting Xia ◽  
Chang-An Wang ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Hybrid Nanoparticles

scholarly journals Experimental Investigation of Thermo-Physical Properties of Tri-Hybrid Nanoparticles in Water-Ethylene Glycol Mixture

2021 ◽  
Vol 18 (8) ◽  
Author(s):  
Anwar Ilmar RAMADHAN ◽  
Wan Hamzah AZMI ◽  
Rizalman MAMAT
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Physical Properties ◽  
Dynamic Viscosity ◽  
Volume Concentration ◽  
Hybrid Nanoparticles ◽  
Maximum Enhancement ◽  
Hybrid Nanofluids ◽  
Thermo Physical Properties

In recent years, research has focused on enhancing the thermo-physical properties of a single component nanofluid. Therefore, hybrid or composite nanofluids have been developed to improve heat transfer performance. The thermo-physical properties of the Al2O3-TiO2-SiO2 nanoparticles suspended in a base of water (W) and ethylene glycol (EG) at constant volume ratio of 60:40 and different volume concentrations were investigated. The experiment was conducted for the volume concentrations of 0.05, 0.1, 0.2, and 0.3% of Al2O3-TiO2-SiO2 nanofluids at different temperatures of 30, 40, 50, 60, and 70 °C. Thermal conductivity and dynamic viscosity measurements were carried out at temperatures ranging from 30 to 70 °C by using KD2 Pro Thermal Properties Analyzer and Brookfield LVDV III Ultra Rheometer, respectively. The highest thermal conductivity for tri-hybrid nanofluids was obtained at 0.3% volume concentration, and the maximum enhancement was increased up to 9% higher than the base fluid (EG/W). Tri-hybrid nanofluids with a volume concentration of 0.05% gave the lowest effective thermal conductivity of 4.8 % at 70 °C temperature. Meanwhile, the dynamic viscosity of the tri-hybrid nanofluids was influenced by volume concentration and temperature. Furthermore, tri-hybrid nanofluids behaved as a Newtonian fluid for volume concentrations from 0.05 to 3.0%. The properties enhancement ratio (PER) estimated that the tri-hybrid nanofluids will aid in heat transfer for all samples in the present. The new correlations for thermal conductivity and dynamic viscosity of tri-hybrid nanofluids were developed with minimum deviation. As a conclusion, the combination of the enhancement in thermal conductivity and dynamic viscosity for tri-hybrid at 0.3% volume concentration was found the optimum condition with more advantage for heat transfer than other concentrations.

scholarly journals Investigation of Counterflow Microchannel Heat Exchanger with Hybrid Nanoparticles and PCM Suspension as a Coolant

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Mushtaq I. Hasan ◽  
Mohammad J. Khafeef ◽  
Omid Mohammadi ◽  
Suvanjan Bhattacharyya ◽  
Alibek Issakhov
Keyword(s):  
Thermal Conductivity ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Pure Water ◽  
Thermal Characteristics ◽  
Hybrid Nanoparticles ◽  
Working Fluid ◽  
Microchannel Heat Exchanger ◽  
Noticeable Increase ◽  
Nanoparticles Concentration

The effect of the hybrid suspension on the intrinsic characteristics of microencapsulated phase change material (MEPCM) slurry used as a coolant in counterflow microchannel heat exchanger (CFMCHE) with different velocities is investigated numerically. The working fluid used in this paper is a hybrid suspension consisting of nanoparticles and MEPCM particles, in which the particles are suspended in pure water as a base fluid. Two types of hybrid suspension are used (Al2O3 + MEPCM and Cu + MEPCM), and the hydrodynamic and thermal characteristics of these suspensions flowing in a CFMCHE are numerically investigated. The results indicated that using hybrid suspension with high flow velocities improves the performance of the microchannel heat exchanger while resulting in a noticeable increase in pressure drop. Thereupon, it causes a decrease in the performance index. Moreover, it was found that the increment of the nanoparticles’ concentration can rise the low thermal conductivity of the MEPCM slurry, but it also leads to a noticeable increase in pressure drop. Furthermore, it was found that as the thermal conductivity of Cu is higher than that for Al2O3, the enhancement in heat transfer is higher in case of adding Cu particles compared with Al2O3 particles. Therefore, the effectiveness of these materials depends strongly on the application at which CFMCHE is employed.

scholarly journals Synthesis and Characterization of Novel Ternary Hybrid Nanoparticles as Thermal Additives in H2O

2021 ◽  
Author(s):  
Mohammed Zayan ◽  
Abdul Khaliq Rasheed ◽  
Akbar John ◽  
Shalini Muniandi ◽  
leo bay fen ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Graphene Oxide ◽  
Hybrid Nanoparticles ◽  
Heat Transfer Medium ◽  
Low Concentrations ◽  
Reduced Graphene ◽  
Thermophysical Characterization ◽  
Newtonian Behavior ◽  
Conductivity Models

The performance of water as a heat transfer medium in numerous applications is limited by its effective thermal conductivity. In order to improve the thermal conductivity of water, herein we report the development and thermophysical characterization of a novel metal-metaloxide-carbon based ternary hybrid nanoparticles (THNp), GO-TiO2-Ag and the rGO-TiO2-Ag. The results indicate that the graphene oxide and reduced graphene oxide based ternary hybrid nanoparticles dispersed in water enhance its thermal conductivity by 66% and 83%, respectively, even at very low concentrations. Mechanisms contributing to this significant enhancement are discussed. The experimental thermal conductivity is plotted against the existing empirical hybrid thermal conductivity correlations. We found that those correlations are not suitable for the metal-metaloxide-carbon combinations, calling for the developing a new thermal conductivity models. The rheological measurements of the nanofluids display non-Newtonian behavior, and the viscosity reduces with the increase in temperature. Such behavior is possibly due to the non-uniform shapes of the ternary hybrid nanoparticles.

The Effect of Ultrasonic Treatment and Gamma Radiation on the Thermal Conductivity of TPNR Hybrid Nanocomposites

2012 ◽  
Vol 626 ◽  
pp. 29-33
Author(s):  
Mou’ad A. Tarawneh ◽  
Sahrim Haji Ahmad
Keyword(s):  
Thermal Conductivity ◽  
Gamma Radiation ◽  
Ultrasonic Treatment ◽  
Treatment Time ◽  
Laser Flash ◽  
Hybrid Nanocomposites ◽  
Hybrid Nanoparticles ◽  
Hybrid Nanocomposite ◽  
Preparation Conditions ◽  
Multi Walled Carbon Nanotubes

This paper discusses the effect of Gamma radiation and ultrasonic treatment time on hybrid nanofillers nanoclay and multi-walled carbon nanotubes (MWCNTs) as reinforcing agents to improve the thermal conductivity of TPNR. The laser flash technique was also employed to determine the thermal conductivity of the hybrid nanocomposite. The thermal conductivity of hybrid nanocomposites that were sintered at 30 to 150 °C did not show a monotonous change with MWCNTs as the filler has a high thermal conductivity compared to nanoclay by using different dose of gamma radiation or with different time of ultrasonic treatment. TEM results showed a combination of intercalated-exfoliated structure of OMMT and the dispersion of MWCNTs in the TPNR composite. The probability that hybrid nanoparticles form a network depends on the interaction between the particles, on their shape (aspect ration), preparation conditions and on their inter-particle distance will control the thermal conductivity of the hybrid nanocomposite.

Nanofluids Containing Hybrid Sphere/Carbon Nanotube Particles

2007 ◽  
Author(s):  
Zenghu Han ◽  
Bao Yang ◽  
S. H. Kim ◽  
M. R. Zachariah
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotube ◽  
Room Temperature ◽  
Thermal Contact Resistance ◽  
Thermal Contact ◽  
Hybrid Nanoparticles ◽  
Particle Volume ◽  
Alpha Olefin ◽  
Wire Method ◽  
New Type

Previous studies on nanofluids have focused on spherical or long-fiber particles. In this work, a new type of complex nanoparticles—hybrid sphere/carbon nanotube (CNT) particle, consisting of numerous CNTs attached to an alumina/iron oxide sphere—is proposed for applications in nanofluids. In such hybrid nanoparticles, heat is expected to transport rapidly from one CNT to another through the center sphere and thus leading to less thermal-contact-resistance between CNTs when compared to simple CNTs dispersed in fluids. CNTs have an extremely high thermal conductivity, but thermal resistance between the CNTs and the fluid has limited their performance in the nanofluids. The proposed hybrid sphere/CNT particles are synthesized by a spray pyrolysis followed by catalytic growth of CNTs. The spheres are about 70 nm in diameter in average, and the attached CNTs have a length up to 2μm. These hybrid nanoparticles are dispersed to poly-alpha-olefin with sonication and a small amount of surfactants to form stable nanofluids. The thermal conductivity of the fluids has been measured by a 3ω-wire method over a temperature range 10–90°C. The results indicate that the effective thermal conductivity of the fluids is increased by about 21% at room temperature for particle volume fractions of 0.2%.

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