Stability and thermal conductivity of tri-hybrid nanofluids for high concentration in water-ethylene glycol (60:40)

2020 ◽  
Vol 10 ◽  
Author(s):  
Anwar Ilmar Ramadhan ◽  
Wan Hamzah Azmi ◽  
Rizalman Mamat
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Ethylene Glycol ◽  
Volume Ratio ◽  
Hybrid Nanofluid ◽  
High Concentration ◽  
Maximum Increase ◽  
Basic Fluid ◽  
Hybrid Nanofluids ◽  
Nanofluid Stability

Background: Research has been focused on improving the thermal properties of single nanofluid components for recent of years. Therefore, hybrid nanofluids or composites have been developed to improve heat transfer performance. Stability and thermal conductivity of the Al2O3-TiO2-SiO2 nanoparticles suspended in the fluid base of water (W) and ethylene glycol (EG) mixture with volume ratio of 60:40. Methods: Experiments were tri-hybrid nanofluid stability was investigated for volume concentration of 0.5 ~ 3.0%, and temperature conditions from 30 to 70 °C for thermal conductivity measurements using a KD2 Pro Thermal Properties Analyzer. The experimental results show that the tri-hybrid nanofluid stability analysis was performed using a stable UVVis method for up to 30 days after preparation with 10 hour sonication time. Results: Comparison of data concentration ratios with sedimentation for single, hybrid, and tri-hybrid nanofluids yielding a stable tri-hybrid nanofluid with 80-90% value. Evaluation of zeta potential for tri-hybrid nanofluids yielded 63.72 mV in excellent stability classification. Sedimentation of this visual observation is influenced by the gravity of the movement of particles in the tube after 30 days. Conclusion: The highest thermal conductivity for tri-hybrid nanofluids was obtained at 3.0% and a maximum increase of up to 27% higher than that of the basic fluid (EG/W). Tri-hybrid nanofluids with a concentration of 0.5% gave the lowest effective thermal conductivity of 13.4% at 70 °C.

scholarly journals Nanofluids, Synthesis and Stability - Brief Review

2021 ◽  
Author(s):  
Jorge Silva-Yumi ◽  
Telmo Moreno Romero ◽  
Gabriela Chango Lescano
Keyword(s):  
Carbon Nanotubes ◽  
Thermal Properties ◽  
Ethylene Glycol ◽  
Aluminum Oxide ◽  
Titanium Oxide ◽  
Silicon Oxide ◽  
Physical Treatment ◽  
Natural Nanoparticles ◽  
Palabras Clave ◽  
Hybrid Nanofluids

Nanofluids constitute an alternative for the most efficient use of energy as they allow generating or improving thermal properties among others of traditional fluids, they are defined as so-called base fluids, such as: water, ethylene glycol, oils, etc., which contain nanoparticles in suspension , such as: aluminum oxide, silicon oxide, titanium oxide, metal nanoparticles, carbon nanotubes, graphene, carbides, etc. Nanofluids can be synthesized by two methods, the nanoparticles can be obtained separately and then the nanofluid is prepared or both nanoparticles and the nanofluid can be prepared simultaneously, an important factor to consider in obtaining nanofluids is their stability. Stability can be achieved by physical treatment or chemical treatment using surfactants. There are many studies about nanofluids, however, most are obtained with synthetic nanoparticles, leaving the use of natural nanoparticles as a field to be explored, as well as other surfactants to improve their stability. Keywords: nanofluids, hybrid nanofluids, nanoparticles, nano refrigerant. Resumen Los nanofluidos constituyen una alternativa para el uso más eficiente de energía pues permiten generar o mejorar las propiedades térmicas entre otras de los fluidos tradicionales, son definidos como fluidos denominados base, como: agua, etilenglicol, aceites, etc., que contienen nanopartículas en suspensión, como: óxido de aluminio, óxido de silicio, óxido de titanio, nanopartículas metálicas, nanotubos de carbono, grafeno, carburos, etc. Los nanofluidos se pueden sintetizar por dos métodos, se pueden obtener las nanopartículas por separado y luego preparar el nanofluido o se puede preparar simultáneamente las nanopartículas y el nanofluido, un factor importante a considerar en la obtención de nanofluidos es su estabilidad. La estabilidad se puede lograr mediante tratamiento físico o tratamiento químico mediante la utilización de surfactantes. Existen muchos estudios acerca de nanofluidos sin embargo, la mayoría se obtienen con nanopartículas sintéticas, quedando el uso de nanopartículas naturales como un campo por explorar al igual que otros surfactantes para mejorar su estabilidad. Palabras Clave: nanofluidos, nonofluidos híbridos, nanoparticulas, nanorefrigerantes.

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.

Thermal Properties of Nanotubes and Nanowires With Acoustically Stiffened Surfaces

2011 ◽  
Author(s):  
Michael F. P. Bifano ◽  
Vikas Prakash
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Specific Heat ◽  
Phonon Dispersion ◽  
Thermal Conductance ◽  
Frequency Equation ◽  
Outer Diameter ◽  
Phonon Confinement ◽  
Maximum Increase ◽  
Acoustic Tuning

A core-shell elasticity model is employed to investigate the effect of a nanowire and nanotube’s increased surface moduli on specific heat, ballistic thermal conductance, and thermal conductivity as a function of temperature. Phonon confinement is analyzed using approximated phonon dispersion relations that result from solutions to the frequency equation of a vibrating rod and tube. The results indicate a maximum 10% decrease in lattice thermal conductivity and ballistic thermal conductance near 160 K for a 10 nm outer diameter nanotube with an inner diameter of 5 nm when the average Young’s Modulus of both the inner and outer free surfaces is increased by a factor of 1.53. In the presence of the acoustically stiffened surfaces, the specific heat of the nanotube is found to decrease by up to 20% at 160 K. Near room temperature, changes in thermal properties are less severe. In contrast, a 10 nm outer diameter nanowire composed of similar material exhibits up to a 12% maximum increase in thermal conductivity at 600 K, a 25% increase in ballistic thermal conductance at 400 K, and a 48% increase in specific heat at 470 K when its outer free surface is acoustically stiffened to the same degree. Our simplified model may be extended to investigate the acoustic tuning of nanowires and nanotubes by inducing surface stiffening or softening via appropriate surface chemical functionalization and coatings.

Analysis of nanofluids as a means of thermal conductivity enhancement in heavy machineries

2014 ◽  
Vol 66 (2) ◽  
pp. 238-243 ◽  
Author(s):  
Ayush Jain ◽  
Imbesat Hassan Rizvi ◽  
Subrata Kumar Ghosh ◽  
P.S. Mukherjee
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Base Fluid ◽  
High Concentration ◽  
Content Type ◽  
Conductivity Enhancement ◽  
Heavy Machinery ◽  
Heat Transfer Fluids ◽  
Experimental Findings

Purpose – Nanofluids exhibit enhanced heat transfer characteristics and are expected to be the future heat transfer fluids particularly the lubricants and transmission fluids used in heavy machinery. For studying the heat transfer behaviour of the nanofluids, precise values of their thermal conductivity are required. For predicting the correct value of thermal conductivity of a nanofluid, mathematical models are necessary. In this paper, the effective thermal conductivity of various nanofluids has been reported by using both experimental and mathematical modelling. The paper aims to discuss these issues. Design/methodology/approach – Hamilton and Crosser equation was used for predicting the thermal conductivities of nanofluids, and the obtained values were compared with the experimental findings. Nanofluid studied in this paper are Al2O3 in base fluid water, Al2O3 in base fluid ethylene glycol, CuO in base fluid water, CuO in base fluid ethylene glycol, TiO2 in base fluid ethylene glycol. In addition, studies have been made on nanofluids with CuO and Al2O3 in base fluid SAE 30 particularly for heavy machinery applications. Findings – The study shows that increase in thermal conductivity of the nanofluid with particle concentration is in good agreement with that predicted by Hamilton and Crosser at typical lower concentrations. Research limitations/implications – It has been observed that deviation between experimental and theoretical results increases as the volume concentration of nanoparticles increases. Therefore, the mathematical model cannot be used for predicting thermal conductivity at high concentration values. Originality/value – Studies on nanoparticles with a standard mineral oil as base fluid have not been considered extensively as per the previous literatures available.

scholarly journals Thermal Performance of Hybrid-Inspired Coolant for Radiator Application

Nanomaterials ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 1100
Author(s):  
F. Benedict ◽  
Amit Kumar ◽  
K. Kadirgama ◽  
Hussein A. Mohammed ◽  
D. Ramasamy ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Capacity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Volume Concentration ◽  
The Other ◽  
Hybrid Nanofluid ◽  
Hybrid Nanofluids ◽  
Tio2 Nanofluids

Due to the increasing demand in industrial application, nanofluids have attracted the considerable attention of researchers in recent decades. The addition of nanocellulose (CNC) with water (W) and ethylene glycol (EG) to a coolant for a radiator application exhibits beneficial properties to improve the efficiency of the radiator. The focus of the present work was to investigate the performance of mono or hybrid metal oxide such as Al2O3 and TiO2 with or without plant base-extracted CNC with varying concentrations as a better heat transfer nanofluid in comparison to distilled water as a radiator coolant. The CNC is dispersed in the base fluid of EG and W with a 60:40 ratio. The highest absorption peak was noticed at 0.9% volume concentration of TiO2, Al2O3, CNC, Al2O3/TiO2, and Al2O3/CNC nanofluids which indicates a better stability of the nanofluids’ suspension. Better thermal conductivity improvement was observed for the Al2O3 nanofluids in all mono nanofluids followed by the CNC and TiO2 nanofluids, respectively. The thermal conductivity of the Al2O3/CNC hybrid nanofluids with 0.9% volume concentration was found to be superior than that of the Al2O3/TiO2 hybrid nanofluids. Al2O3/CNC hybrid nanofluid dominates over other mono and hybrid nanofluids in terms of viscosity at all volume concentrations. CNC nanofluids (all volume concentrations) exhibited the highest specific heat capacity than other mono nanofluids. Additionally, in both hybrid nanofluids, Al2O3/CNC showed the lowest specific heat capacity. The optimized volume concentration from the statistical analytical tool was found to be 0.5%. The experimental results show that the heat transfer coefficient, convective heat transfer, Reynolds number and the Nusselt number have a proportional relationship with the volumetric flow rate. Hybrid nanofluids exhibit better thermal conductivity than mono nanofluids. For instance, a better thermal conductivity improvement was shown by the mono Al2O3 nanofluids than the CNC and TiO2 nanofluids. On the other hand, superior thermal conductivity was observed for the Al2O3/CNC hybrid nanofluids compared to the other mono and hybrid ones (Al2O3/TiO2).

scholarly journals Thermal conductivity enhancement in gold decorated graphene nanosheets in ethylene glycol based nanofluid

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
M. C. Mbambo ◽  
M. J. Madito ◽  
T. Khamliche ◽  
C. B. Mtshali ◽  
Z. M. Khumalo ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Base Fluid ◽  
Graphene Nanosheets ◽  
Synthesis Method ◽  
Particle Diameter ◽  
Laser Wavelength ◽  
Hybrid Nanofluid ◽  
Average Particle ◽  
Conductivity Enhancement

Abstract We report on the synthesis and thermal conductivity of gold nanoparticles (AuNPs) decorated graphene nanosheets (GNs) based nanofluids. The GNs-AuNPs nanocomposites were synthesised using a nanosecond pulsed Nd:YAG laser (wavelength = 1,064 nm) to ablate graphite target followed by Au in ethylene glycol (EG) base fluid to obtain GNs-AuNPs/EG hybrid nanofluid. The characterization of the as-synthesised GNs-AuNPs/EG hybrid nanofluid confirmed a sheet-like structure of GNs decorated with crystalline AuNPs with an average particle diameter of 6.3 nm. Moreover, the AuNPs appear smaller in the presence of GNs which shows the advantage of ablating AuNPs in GNs/EG. The thermal conductivity analysis in the temperature range 25–45 °C showed that GNs-AuNPs/EG hybrid nanofluid exhibits an enhanced thermal conductivity of 0.41 W/mK compared to GNs/EG (0.35 W/mK) and AuNPs/EG (0.39 W/mK) nanofluids, and EG base fluid (0.33 W/mK). GNs-AuNPs/EG hybrid nanofluid displays superior enhancement in thermal conductivity of up to 26% and this is due to the synergistic effect between AuNPs and graphene sheets which have inherent high thermal conductivities. GNs-AgNPs/EG hybrid nanofluid has the potential to impact on enhanced heat transfer technological applications. Also, this work presents a green synthesis method to produce graphene-metal nanocomposites for various applications.

scholarly journals Investigation of the Thermal Conductivity, Viscosity, and Thermal Performance of Graphene Nanoplatelet-Alumina Hybrid Nanofluid in a Differentially Heated Cavity

2021 ◽  
Vol 9 ◽  
Author(s):  
Adeola O. Borode ◽  
Noor A. Ahmed ◽  
Peter A. Olubambi ◽  
Mohsen Sharifpur ◽  
Josua P. Meyer
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Performance ◽  
Temperature Gradients ◽  
Hybrid Nanofluid ◽  
Mixing Ratio ◽  
Graphene Nanoplatelet ◽  
Hybrid Nanomaterial ◽  
Mixing Ratios ◽  
Hybrid Nanofluids

This paper investigates the thermophysical properties and heat transfer performance of graphene nanoplatelet (GNP) and alumina hybrid nanofluids at different mixing ratios. The electrical conductivity and viscosity of the nanofluids were obtained at temperatures between 15–55°C. The thermal conductivity was measured at temperatures between 20–40°C. The natural convection properties, including Nusselt number, Rayleigh number, and heat transfer coefficient, were experimentally obtained at different temperature gradients (20, 25, 30, and 35°C) in a rectangular cavity. The Mouromtseff number was used to theoretically estimate all the nanofluids’ forced convective performance at temperatures between 20–40°C. The results indicated that the thermal conductivity and viscosity of water are increased with the hybrid nanomaterial. On the other hand, the viscosity and thermal conductivity of the hybrid nanofluids are lesser than that of mono-GNP nanofluids. Notwithstanding, of all the hybrid nanofluids, GNP-alumina hybrid nanofluid with a mixing ratio of 50:50 and 75:25 were found to have the highest thermal conductivity and viscosity, enhancing thermal conductivity by 4.23% and increasing viscosity by 15.79%, compared to water. Further, the addition of the hybrid nanomaterials improved the natural convective performance of water while it deteriorates with mono-GNP. The maximum augmentation of 6.44 and 10.48% were obtained for Nuaverage and haverage of GNP-Alumina (50:50) hybrid nanofluid compared to water, respectively. This study shows that hybrid nanofluids are more effective for heat transfer than water and mono-GNP nanofluid.

COMPARISON OF THERMAL CONDUCTIVITY FOR HHT-24-CNF-BASED NANOFLUID USING DEIONIZED WATER AND ETHYLENE GLYCOL

2015 ◽  
Vol 77 (21) ◽  
Author(s):  
Syarifah Norfatin Syed Idrus ◽  
Nor Salihah Zaini ◽  
Imran Syakir Mohamad ◽  
Norli Abdullah ◽  
Mohd Haizal Mohd Husin
Keyword(s):  
Thermal Conductivity ◽  
Thermal Properties ◽  
Ethylene Glycol ◽  
Carbon Nanofibers ◽  
Deionized Water ◽  
Water Based

Carbon nanofibers (CNF) is one of potential nanoparticles that possess superior thermal conductivity. In this study, nanofluids with suspension of CNF in deionized water (DI water) and ethylene glycol (EG) are prepare. Thermal conductivity (TC) of the nanofluids are measured at 6°C, 25°C and 40°C using KD2 Pro Thermal Properties Analyser. The results show that, TC increases with increasing of temperature and CNF loading. Best TC is recorded by 36.7 % enhancement at 40 °C for EG based fluid with 0.9 wt% CNF loading. Meanwhile, for DI water based fluid, best TC enhancement (39.6 %) can be achieved with CNF loading of 0.7 wt% at 40°C. Overall, both based fluid show a promising enhancement in thermal conductivity. However, DI water based fluid show higher TC in comparison to EG based fluid due to the higher TC in standard DI water itself.

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