Thermal Conductivity Analysis of Ethylene Glycol/H2O- Based MgFe2O4 Ferrofluid

2022 ◽  
Vol 1048 ◽  
pp. 83-88
Author(s):  
K. Ajith ◽  
Archana Sumohan Pillai ◽  
I.V. Muthu Vijayan Enoch ◽  
A. Brusly Solomon
Keyword(s):  
Thermal Conductivity ◽  
Magnetic Flux ◽  
Surface Morphology ◽  
Ethylene Glycol ◽  
Structural Characterization ◽  
Magnetic Nanoparticle ◽  
Volume Fraction ◽  
Current Investigation ◽  
Step Method ◽  
Volume Fractions

The current investigation aims to synthesize MgFe2O4 magnetic nanoparticle and measure the thermal conductivity of MgFe2O4 ferrofluid. Prepared MgFe2O4 nanoparticle's structural characterization, the concentration of constituents, and surface morphology were analyzed using XRD, EDAX, and TEM respectively. This study also analyses the influence of magnetic flux on the thermal conductivity of MgFe2O4/ EG: H2O (60:40) based ferrofluids formed by the two-step method. Thermal conductivity of ferrofluid measured at different volume fractions (ranging from 0.01% to 0.20%) show that thermal conductivity augmented with an escalation in volume fraction and the highest enhancement of 10.32% was reached at 0.20% volume fraction. Results indicate that the applied magnetic flux improves the thermal conductivity of ferrofluid from 10.32% to 14.75% at 0.20% volume fraction and 350 Gauss Magnetic flux.

scholarly journals Heat transfer studies in compact heat exchanger using ZnO and TiO2 nanofluids in ethylene glycol/water

2018 ◽  
Vol 24 (4) ◽  
pp. 309-318
Author(s):  
Srinivasan Manikandan ◽  
Rajoo Baskar
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Ethylene Glycol ◽  
Volume Fraction ◽  
Inlet Temperature ◽  
Percentage Increase ◽  
Cold Side ◽  
Volume Fractions ◽  
Experimental Values ◽  
Tio2 Nanofluids

This paper reports an experimental study on the heat transfer characteristics of a nanofluid consisting of ZnO/water/ethylene glycol (EG) and TiO2/water/ /ethylene glycol. In this study, the base fluids of ethylene glycol (EG):water (W) with volume fractions of 30:70, 40:60, and 50:50 were prepared, and 0.2 to 1.0 volume fractions of ZnO and TiO2 nanofluids were used as a cold side fluid. The prime objective of this study is to identify the effects of nanofluid concentration and three different hot fluid inlet temperatures viz., 55, 65 and 75?C C on the heat transfer enhancement of cold side fluid. The results are compared with base fluids and the percentage increase of the Nusselt number because of nanoparticle addition is noted both experimentally and theoretically. The results showed that at the hot fluid inlet temperature of 75?C, the increase in the Nusselt number is maximum with volume concentrations of 0.6 and 0.8% for ZnO and TiO2 nanofluids, respectively. The corresponding maximum Nusselt number enhancements are about 11.5 and 21.4%, respectively, for the base fluid volume fraction of 30:70 (EG:W). There is good agreement between the results calculated from experimental values and the correlation.

Influence of Mesocarp Fibre Inclusion on Thermal Properties of Foamed Concrete

2021 ◽  
Vol 87 (1) ◽  
pp. 1-11
Author(s):  
Siti Shahirah Suhaili ◽  
Md Azree Othuman Mydin ◽  
Hanizam Awang
Keyword(s):  
Thermal Conductivity ◽  
Heat Capacity ◽  
Thermal Properties ◽  
Thermal Diffusivity ◽  
Specific Heat ◽  
Specific Heat Capacity ◽  
Volume Fraction ◽  
Thermal Constant ◽  
Volume Fractions ◽  
Foamed Concrete

The addition of mesocarp fibre as a bio-composite material in foamed concrete can be well used in building components to provide energy efficiency in the buildings if the fibre could also offer excellent thermal properties to the foamed concrete. It has practical significance as making it a suitable material for building that can reduce heat gain through the envelope into the building thus improved the internal thermal comfort. Hence, the aim of the present study is to investigate the influence of different volume fractions of mesocarp fibre on thermal properties of foamed concrete. The mesocarp fibre was prepared with 10, 20, 30, 40, 50 and 60% by volume fraction and then incorporated into the 600, 1200 and 1800 kg/m3 density of foamed concrete with constant cement-sand ratio of 1:1.5 and water-cement ratio of 0.45. Hot disk thermal constant analyser was used to attain the thermal conductivity, thermal diffusivity and specific heat capacity of foamed concrete of various volume fractions and densities. From the experimental results, it had shown that addition of mesocarp fibre of 10-40% by volume fraction resulting in low thermal conductivity and specific heat capacity and high the thermal diffusivity of foamed concrete with 600 and 1800 kg/m3 density compared to the control mix while the optimum amount of mesocarp fibre only limit up to 30% by volume fraction for 1200 kg/m3 density compared to control mix. The results demonstrated a very high correlation between thermal conductivity, thermal diffusivity and specific heat capacity which R2 value more than 90%.

Experimental and Theoretical Studies of Thermophysical Properties of MgO-Water Nanofluid

2020 ◽  
Vol 1008 ◽  
pp. 47-52
Author(s):  
Abdallah Yousef Mohammed Ali ◽  
Ahmed Hassan El-Shazly ◽  
Marwa Farouk El-Kady ◽  
Hesham Ibrahim Elqady ◽  
Kholoud Madih ◽  
...  
Keyword(s):  
Thermal Conductivity ◽  
Thermophysical Properties ◽  
Volume Fraction ◽  
Sol Gel ◽  
Solid Volume Fraction ◽  
Ammonium Bromide ◽  
Distilled Water ◽  
Step Method ◽  
Mgo Nanoparticles ◽  
Cetyl Trimethyl Ammonium

Magnesium oxide (MgO) nanoparticles were synthesized using the sol-gel technique then characterized. Cetyl Trimethyl Ammonium Bromide (CTAB) surfactant was added to reduce Van der Waal forces among MgO nanoparticles and distilled water forming a stable nanofluid using two-step method with aid of ultrasound sonication. Pure distilled water and nanofluids with different volume fractions of 0.25, 0.5, 0.75, and 1% are used as working fluids. Thermophysical properties of prepared nanofluids were measured experimentally and determined theoretically. Effect of solid volume fraction on the thermophysical properties; including thermal conductivity, heat capacity, viscosity, and density of MgO-water nanofluids are discussed. Moreover, experimental results have been compared with the suitable correlations for MgO-water nanofluid. The findings show that thermal conductivity, viscosity, and density of nanofluid increases with increasing solid volume fraction.

scholarly journals Synthesis of hybrid nanofluid with two-step method

2018 ◽  
Vol 67 ◽  
pp. 03057 ◽  
Author(s):  
Wayan Nata Septiadi ◽  
Ida Ayu Nyoman Titin Trisnadewi ◽  
Nandy Putra ◽  
Iwan Setyawan
Keyword(s):  
Thermal Conductivity ◽  
Base Fluid ◽  
Volume Fraction ◽  
Heat Transfer Fluid ◽  
Hybrid Nanofluid ◽  
Test Results ◽  
Step Method ◽  
Fluid Mixture ◽  
High Level ◽  
Better Than

Nanofluid is a liquid fluid mixture with a nanometer-sized solid particle potentially applied as a heat transfer fluid because it is capable of producing a thermal conductivity better than a base fluid. However, nanofluids have a weakness that is a high level of agglomeration as the resulting conductivity increases. Therefore, in this study, the synthesis of two nanoparticles into the base fluid called hybrid nanofluids. This study aims to determine the effect of nanoparticle composition on the highest thermal conductivity value with the lowest agglomeration value. This research was conducted by dispersing Al2O3-TiO2 nanoparticles in water with volume fraction of 0.1%, 0.3%, 0.5%, 0.7% in the composition of Al2O3-TiO2 ratio of 75%:25%, 50%:50%, 25%:75%. The synthesis was performed with a magnetic stirrer for 30 minutes. The tests were carried out in three types: thermal conductivity testing with KD2, visual agglomeration observation and absorbance measurements using UV-Vis, wettability testing with HSVC tools and Image applications. The test results showed that the ratio composition ratio of 75% Al2O3-25% TiO2 with a volume fraction of 0.7% resulted in an increase in optimum thermal conductivity with the best wettability and the longest agglomeration level.

Micromechanical analysis for transverse thermal conductivity of composites

2010 ◽  
Vol 45 (11) ◽  
pp. 1245-1255 ◽  
Author(s):  
Sangwook Sihn ◽  
Ajit K. Roy
Keyword(s):  
Thermal Conductivity ◽  
Numerical Solutions ◽  
Volume Fraction ◽  
Numerical Models ◽  
Matrix Material ◽  
Analytic Solutions ◽  
Fiber Distribution ◽  
Fiber Volume ◽  
Volume Fractions ◽  
Transverse Thermal Conductivity

Micromechanical analyses were conducted for the prediction of transverse thermal conductivity of laminated composites. We reproduced and reinvestigated both analytic and numerical models with regular and randomly distributed fibers in matrix material. A parametric study was conducted for wide ranges of fiber volume fractions and fiber-to-matrix thermal conductivity ratios. The numerical solutions using finite element (FE) analysis were compared with various analytic solutions from simple and enhanced rule or mixtures and an effective inclusion method (EIM). It was found that the EIM yields a reasonably agreeable solution with the FE solution using a hexagonal-array of regular fiber distribution for wide ranges of fiber volume fraction and fiber-to-matrix thermal conductivity ratios, which makes the EIM a useful method in predicting various multiphysical transverse properties of composites. Comparison of the results from the regular- and random-fiber models indicates that the transverse thermal conductivity of composites can significantly be affected by the random fiber distributions, especially at high fiber volume fractions. A similar conclusion was made for the foams with random pore distribution. It was shown that the predictions with the random fiber distribution agree well with the experimental data.

scholarly journals Thermophysical Properties of Nanofluids Composed of Ethylene Glycol and Long Multi-Walled Carbon Nanotubes

Fluids ◽  
2020 ◽  
Vol 5 (4) ◽  
pp. 241
Author(s):  
Karolina Brzóska ◽  
Bertrand Jóźwiak ◽  
Adrian Golba ◽  
Marzena Dzida ◽  
Sławomir Boncel
Keyword(s):  
Thermal Conductivity ◽  
Carbon Nanotubes ◽  
Ethylene Glycol ◽  
Chemical Vapor ◽  
Step Method ◽  
Mwcnt Content ◽  
Multi Walled Carbon Nanotubes ◽  
The Stability ◽  
Walled Carbon Nanotubes ◽  
Rotary Viscometer

In this work, thermal conductivity, viscosity, isobaric heat capacity, and density of stable carbon-based nanofluids are presented. The nanofluids under study are composed of 1,2-ethanediol (ethylene glycol, EG) and long multi-walled carbon nanotubes (MWCNTs), so-called ‘in-house 16h’ (synthesized in our laboratory via catalytic chemical vapor deposition during 16 h with a diameter of 60–80 nm and length of 770 μm). Poly(N-vinylpyrrolidone) (PVP) was used to increase the stability of nanofluids. The nanofluids were prepared via an ultrasonication-assisted, three-step method while their key thermophysical characteristics were obtained using the hot-wire technique and rotary viscometer. As a result, the addition of MWCNTs significantly improved the thermal conductivity of nanofluids by 31.5% for the highest 1.0 wt% (0.498 vol%) long MWCNT content, leaving the Newtonian character of the nanofluids practically intact.

Experimental Investigation for the Thermo-physical Properties and Stability of CeO2, ZrO2, and Al2O3 Mixed with Ethylene Glycol and Distilled Water

2019 ◽  
Vol 70 (11) ◽  
pp. 3908-3912
Author(s):  
Altayyeb Alfaryjat ◽  
Mariana Florentina Stefanescu ◽  
Alexandru Dobrovicescu
Keyword(s):  
Thermal Conductivity ◽  
Experimental Investigation ◽  
Ethylene Glycol ◽  
Physical Properties ◽  
Visual Observation ◽  
Distilled Water ◽  
Step Method ◽  
Nanoparticles Concentration ◽  
Thermo Physical Properties

In this work, the effects of nanoparticles concentration on the density, thermal conductivity, and viscosity of Al2O3, CeO2 and ZrO2 suspended in 20% of ethylene glycol (EG) and 80% of distilled water (DW) is experimentally investigated. By using two step method, the nanofluid samples are provided at different concentrations, including 0.5%, 1% and 2 %. Visual observation of the nanofluid samples showed that CeO2-EG/DW and ZrO2-EG/DW have higher stability for one week more that Al2O3-EG/DW. The results indicate that the density, viscosity and thermal conductivity of the nanofluids increased with increasing the nanoparticles concentration. The highest enhancement of the thermal conductivity was found to be 9.6% for 2% concentration of CeO2-EG/DW at 25�C. Al2O3-EG/DW shows the lowest density and viscosity between all types of the nanofluids.

scholarly journals Empirical correlations to predict thermophysical and heat transfer characteristics of nanofluids

2008 ◽  
Vol 12 (2) ◽  
pp. 27-37 ◽  
Author(s):  
Vasu Velagapudi ◽  
Krishna Konijeti ◽  
Kumar Aduru
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Volume Fraction ◽  
Solid Particles ◽  
Engine Oil ◽  
Fluid Temperature ◽  
Flow Conditions ◽  
Thermophysical Characteristics ◽  
Laminar And Turbulent Flow

Nanofluids exhibits larger thermal conductivity due to the presence of suspended nanosized solid particles in them such as Al2O3, Cu, CuO,TiO2, etc. Varieties of models have been proposed by several authors to explain the heat transfer enhancement of fluids such as water, ethylene glycol, engine oil containing these particles. This paper presents a systematic literature survey to exploit the thermophysical characteristics of nanofluids. Based on the experimental data available in the literature empirical correlation to predict the thermal conductivity of Al2O3, Cu, CuO, and TiO2 nanoparticles with water and ethylene glycol as base fluid is developed and presented. Similarly the correlations to predict the Nusselt number under laminar and turbulent flow conditions is also developed and presented. These correlations are useful to predict the heat transfer ability of nanofluids and takes care of variations in volume fraction, nanoparticle size and fluid temperature. The improved thermophysical characteristics of a nanofluid make it excellently suitable for future heat exchange applications. .

Modeling Thermal Conductivity of Aligned CNT-Matrix Composites With Increasing Volume Fraction

2016 ◽  
Author(s):  
Diana Grandio ◽  
Drazen Fabris
Keyword(s):  
Thermal Conductivity ◽  
Effective Thermal Conductivity ◽  
Volume Fraction ◽  
Particle Interaction ◽  
Longitudinal Direction ◽  
Near Neighbor ◽  
Correction Function ◽  
Matrix Composites ◽  
Particle Volume ◽  
Volume Fractions

In prior work an effective medium approach (EMA) has been developed to evaluate composite physical properties such as thermal conductivity, dielectric function or elastic modulus (C.-W. Nan, Prog. Mat. Sci. V. 37, 1993). This model combined with the Kapitza interface resistance can predict the effective thermal conductivity of randomly dispersed long fibers for a very low volume fraction (f < 0.01). The present study compares finite-element (FEA) computations and the EMA model for CNT-matrix compositions with low to moderate volume fractions, 0.001 to 0.02. The FEA results obtained show that the EMA model underestimates the effective thermal conductivity of the composite when the particles are very close to each other, even for small particle volume fractions. For aligned fibers the Kaptiza resistance cannot be neglected in the longitudinal direction. This paper proposes a general correction function for the dependence on particle to particle interaction based on the near neighbor distances and the number of near neighbors. This correction function reduces the EMA under prediction to within several percent (< 5%) in most cases.

The Thermal Transport Properties of Ethylene Glycol Based MGO Nanofluids

2009 ◽  
Author(s):  
Wei Yu ◽  
Hua-Qing Xie ◽  
Yang Li ◽  
Li-Fei Chen
Keyword(s):  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Transport Properties ◽  
Volume Fraction ◽  
Metallic Oxide ◽  
Mgo Nanoparticles ◽  
Conductivity Enhancement ◽  
Classical Models ◽  
Constant Viscosity ◽  
Solid Liquid

Ethylene glycol based nanofluids containing MgO nanoparticles (MgO-EG) were prepared, and the transport properties including thermal conductivity and viscosity were measured. The results show that the thermal conductivity of MgO-EG nanofluid depends strongly on particle concentration, and it increases nonlinearly with the volume fraction of nanoparticles. The thermal conductivity of MgO-EG nanofluids is larger than that of nanofluids containing the same volume fraction of TiO2, ZnO, Al2O3 and SiO2, maybe due to its lowest viscosity among the tested metallic oxide nanofluids. Thermal conductivity enhancement of MgO-EG nanofluids appears weak dependence on temperature from 10 to 60°C, and the enhanced ratios are almost constant. Viscosity measurements show that MgO-EG nanofluids demonstrate Newtonian behavior, and the viscosity significantly decreases with temperature. The thermal conductivity and viscosity increments of nanofluids are higher than those of the existing classical models for the solid-liquid mixture.

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