An Experimental Determination of the Viscosity of Propylene Glycol/Water Based Nanofluids and Development of New Correlations

2015 ◽  
Vol 137 (8) ◽  
Author(s):  
Ravikanth S. Vajjha ◽  
Debendra K. Das ◽  
Godwin A. Chukwu
Keyword(s):  
Experimental Data ◽  
Carbon Nanotubes ◽  
Propylene Glycol ◽  
Base Fluid ◽  
Volume Concentration ◽  
Plastic Behavior ◽  
Average Particle ◽  
Particle Volume ◽  
Temperature Range ◽  
Newtonian Behavior

Measurements have been carried out for determining the viscosity of several nanofluids, in which different nanoparticles were dispersed in a base fluid of 60% propylene glycol (PG) and 40% water by mass. The nanoparticles were aluminum oxide (Al2O3), copper oxide (CuO), silicon dioxide (SiO2), titanium oxide (TiO2), and zinc oxide (ZnO) with different average particle diameters. Measurements were conducted for particle volume concentrations of up to 6% and over a temperature range of 243 K–363 K. All the nanofluids exhibited a Bingham plastic behavior at lower temperatures of 243 K–273 K and a Newtonian behavior in the temperature range of 273 K–363 K. Comparisons of the experimental data with several existing models show that they do not exhibit good agreement. Therefore, a new model has been developed for the viscosity of nanofluids as a function of temperature, particle volume concentration, particle diameter, the properties of nanoparticles, and those of the base fluid. Measurements were also conducted for single walled, bamboolike structured, and hollow structured multiwalled carbon nanotubes (MWCNT) dispersed in a base fluid of 20% PG and 80% water by mass. Measurements of these carbon nanotubes (CNT) nanofluids were conducted for a particle volume concentration of 0.229% and over a temperature range of 273 K–363 K, which exhibited a non-Newtonian behavior. The effect of ultrasonication time on the viscosity of CNT nanofluids was investigated. From the experimental data of CNT nanofluids, a new correlation was developed which relates the viscosity to temperature and the Péclet number.

Experimental Investigations to Study the Effect on Coefficient of Friction and Heat Transfer Coefficient in the Lubricants With Nano Blending

2017 ◽  
Author(s):  
Lvrsv Prasad Chilamkurti ◽  
Isai Dharma Rao ◽  
K. Santarao
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Coefficient Of Friction ◽  
Frictional Force ◽  
Room Temperature ◽  
Volume Concentration ◽  
Nano Particles ◽  
Average Particle ◽  
Particle Volume

Worm gears are unique in their ability to achieve large speed reductions in a compact space with gear ratios of 20:1, 60:1 and 200:1 or even higher in some cases and have transmission efficiency between 50% and 70%. One of the major drawback in worm drive design is the relative motion between the two mating elements is entirely sliding. This sliding motion continuously expels the lubricant aside leading to higher wear and increase in temperature. This phenomenon leads to high wear and higher temperatures, which are the limiting factors in the worm drives. Nano particles have gained a greater attention in the recent years because of their highly enhanced thermal and tribological properties when blended with conventional lubricants. In the present investigations the addition of Al2O3 nano particles with average particle size of 30 nm in SAE 140 gear oil resulted in reducing the coefficient of friction, wear and enhanced the heat transfer coefficient. It is observed that coefficient of friction is decreased by 8.98%, 10.11% and 16.85% at nano particle volume concentration of 0.1%, 0.2% and 0.5% respectively at room temperature. Frictional force was found reduced by 26.02% at room temperature for 0.5% volume concentration. Further it was also noted 32.25% and 18.55% reduction in frictional force at the temperatures 60°C and 90°C respectively for 0.2% volume concentration. Convective heat transfer coefficient is increased with increasing particle volume concentration and maximum enhancement of 46.35% in heat transfer coefficient observed at 0.5% volume fraction. The results depict that lubricants blended with nano particles exhibit enhanced tribological and heat transfer properties.

Aggregation Inducing Abnormal Viscosity Increase in Graphite Nanofluids

2012 ◽  
Author(s):  
T. F. Wong ◽  
A. Crivoi ◽  
Fei Duan
Keyword(s):  
Shear Rate ◽  
Effective Viscosity ◽  
Volume Concentration ◽  
Particle Volume ◽  
Nanoparticle Aggregation ◽  
Maximum Enhancement ◽  
Holding Period ◽  
Viscosity Increase ◽  
Best Fitting ◽  
Newtonian Behavior

The effect of aggregation on the viscosity was experimentally investigated in the graphite water-based nanofluids. The shear thinning non-Newtonian behavior is observed in the effective viscosity measurement with the shear rate in the nanofluids. On the basis of the best fitting of the experimental data, the viscosities at zero shear rate and at infinite shear rate are determined. As a function of the particle volume concentration and holding period of the nanofluids after preparation, the effective viscosity the increases. The maximum enhancement of the viscosity at infinite rate of shear is over 24 times higher in the 4 vol % 3-day nanofluids compared with the base fluid. A scanning electron microscope was applied to reveal the morphology of aggregated nanoparticles in the nanofluids. The large and irregular aggregation of the particles is found if the nanofluids were kept for three days. Experimental results indicate that the abnormal effective viscosity increase of nanofluids is related to the nanoparticle aggregation in their base fluids.

Fluid-particle Drag Force in Binary-solid Suspensions

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Renzo Di Felice ◽  
Marco Rotondi
Keyword(s):  
Experimental Data ◽  
Drag Force ◽  
Single Particle ◽  
Relative Velocity ◽  
Volume Concentration ◽  
Particle Suspensions ◽  
Particle Volume ◽  
Theoretical Support ◽  
Solid Suspension

The drag force on a particle in a multiparticle suspension is a function of the particle-fluid relative velocity and of the particle volume concentration. Its determination heavily relies on experimental observations, as theoretical support is still limited to viscous flow regime and dilute solid concentrations. When uniform particle suspensions are considered, there is a certain abundance of experimental data available which has permitted the proposition of simple and reliable relationships for the determination of the drag force: these relationships are normally expressed through the use of the so-called “voidage function”, i.e. a function by which the drag force on an isolated particle has to be multiplied in order to obtain the drag force on a particle in a multiparticle suspension. The extension of the approach mentioned above to suspensions made up of particles differing in size and density has been attempted here and new simple relationships are presented for the case of binary-solid systems. The basic idea draws an analogy between binary-solid suspension and single-particle suspensions thereby making possible the use of well established results. The simple relationships obtained for the estimation of the drag force on a particle in a binary-solid suspension have been tested, with satisfactory success, against experimental data available in literature.

scholarly journals Electrical Conductivity of New Nanoparticle Enhanced Fluids: An Experimental Study

Nanomaterials ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 1228 ◽  
Author(s):  
Chereches ◽  
Minea
Keyword(s):  
Experimental Data ◽  
Electrical Conductivity ◽  
Base Fluid ◽  
Volume Concentration ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Sio2 Nanoparticles ◽  
Theoretical Models ◽  
Conductivity Ratio ◽  
Hybrid Nanofluids

In this research, the electrical conductivity of simple and hybrid nanofluids containing Al2O3, TiO2 and SiO2 nanoparticles and water as the base fluid was experimentally studied at ambient temperature and with temperature variation in the range of 20–60 °C. A comparison of the experimental data with existing theoretical models demonstrated that the theoretical models under-predict the experimental data. Consequently, several correlations were developed for nanofluid electrical conductivity estimation in relation to temperature and volume concentration. The electrical conductivity of both simple and hybrid nanofluids increased linearly with both volume concentration and temperature upsurge. More precisely, by adding nanoparticles to water, the electrical conductivity increased from 11 times up to 58 times for both simple and hybrid nanofluids, with the maximum values being attained for the 3% volume concentration. Plus, a three-dimensional regression analysis was performed to correlate the electrical conductivity with temperature and volume fraction of the titania and silica nanofluids. The thermo-electrical conductivity ratio has been calculated based on electrical conductivity experimental results and previously determined thermal conductivity. Very low figures were noticed. Concluding, one may affirm that further experimental work is needed to completely elucidate the behavior of nanofluids in terms of electrical conductivity.

Measurements of Densities of Propylene Glycol-Based Nanofluids and Comparison With Theory

2016 ◽  
Vol 8 (2) ◽  
Author(s):  
Jagannadha R. Satti ◽  
Debendra K. Das ◽  
Dustin R. Ray
Keyword(s):  
Copper Oxide ◽  
Propylene Glycol ◽  
Base Fluid ◽  
Maximum Error ◽  
Theoretical Equation ◽  
Maximum Deviation ◽  
Average Deviation ◽  
Density Measurements ◽  
Temperature Range ◽  
American Society

Density measurements were performed on several nanofluids containing nanoscale particles of aluminum oxide (Al2O3), zinc oxide (ZnO), copper oxide (CuO), titanium oxide (TiO2), and silicon dioxide (SiO2). These particles were individually dispersed in a base fluid of 60:40 propylene glycol and water (PG/W) by volume. Additionally, carbon nanotubes (CNTs) dispersed in de-ionized water (DI) was also tested. Initially, a benchmark test was performed on the density of the base fluid in the temperature range of 0–90 °C. The measured data agreed within a maximum error of 1.6% with the values presented in the handbook of American Society of Heating, Refrigerating, and Air Conditioning Engineers (ASHRAE). After this validation run, the density measurements of various nanofluids with nanoparticle volumetric concentrations from 0 to 6% and nanoparticle sizes ranging from 10 to 76 nm were performed. The temperature range of the measurements was from 0 to 90 °C. These results were compared with the values predicted by a currently acceptable theoretical equation for nanofluids. The experimental results showed good agreement with the theoretical equation with a maximum deviation of −3.8% for copper oxide nanofluid and average deviation of −0.1% for all the nanofluids tested.

Measuring and ANFIS Modelling for Thermal Conductivity of Cu/Zn Bimetallic Nanofluids

2014 ◽  
Vol 663 ◽  
pp. 311-316
Author(s):  
H.H. Balla ◽  
Shahrir Abdullah ◽  
Wan Mohd Faizal Wan Mahmood ◽  
Zulkifli R. ◽  
K. Sopian
Keyword(s):  
Thermal Conductivity ◽  
Base Fluid ◽  
Volume Concentration ◽  
Measured Data ◽  
Core Shell ◽  
Transient Hot Wire ◽  
Hot Wire ◽  
Particle Volume ◽  
Anfis Model ◽  
Thermo Physical Properties

The enhancement of the thermo-physical properties for working fluids reduces many limitations in the car design such as reduce the size of the car radiator as well as increase thermal efficiency of the engine. A fluid with a suspension of nanometre size particles is called a nanofluid, which has the higher thermal properties than its base fluid. A bimetallic core/shell Cu/Zn nanoparticle was suspended in a base fluid to prepare a nanofluid. A coated transient hot wire apparatus was used to measure the thermal conductivity of the nanofluid for bimetallic ratio, volume factions, and temperature of the base fluid. Then the ANFIS model was used to modeling the measured data. The comparisons of thermal conductivity of bimetallic Cu/Zn nanofluids with the monocular Zn and Cu metallic nanofluids are presented. It is found that thermal conductivity increases with the particle volume concentration. However, the shape of the nanoparticles demonstrates anomalous enhancement in thermal conductivity of bimetallic than monocular metallic nanofluid.

Effects of Multiple Impacts and Size Distribution of Particles on Erosion Predictions Using CFD

2007 ◽  
Author(s):  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirzai
Keyword(s):  
Experimental Data ◽  
Particle Size ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Target Material ◽  
Average Particle ◽  
Multiple Impacts ◽  
Cfd Simulations ◽  
Erosion Damage ◽  
Wide Range

Erosion equations are usually obtained from experiments by impacting solid particles entrained in a gas or liquid on a target material. The erosion equations are utilized in CFD (Computational Fluid Dynamics) models to predict erosion damage caused by solid particle impingements. Many erosion equations are provided in terms of an erosion ratio. By definition, the erosion ratio is the mass loss of target material divided by the mass of impacting particles. The mass of impacting particles is the summation of (particle mass × number of impacts) of each particle. In erosion experiments conducted to determine erosion equations, some particles may impact the target wall many times and some other particles may not impact the target at all. Therefore, the experimental data may not reflect the actual erosion ratio because the mass of the sand that is used to run the experiments is assumed to be the mass of the impacting particles. CFD and particle trajectory simulations are applied in the present work to study effects of multiple impacts on developing erosion ratio equations. The erosion equation as well as the CFD-based erosion modeling procedure is validated against a variety of experimental data. The results show that the effect of multiple impacts is negligible in air cases. In water cases, however, this effect needs to be accounted for especially for small particles. This makes it impractical to develop erosion ratio equations from experimental data obtained for tests with sand in water or dense gases. Many factors affecting erosion damage are accounted for in various erosion equations. In addition to some well-studied parameters such as particle impacting speed and impacting angle, particle size also plays a significant role in the erosion process. An average particle size is usually used in analyzing experimental data or estimating erosion damage cases of practical interest. In petroleum production applications, however, the size of sand particles that are entrained in produced fluids can vary over a fairly broad range. CFD simulations are also performed to study the effect of particle size distribution. In CFD simulations, particle sizes are normally distributed with the mean equaling the average size of interest and the standard deviation varying over a wide range. Based on CFD simulations, an equation is developed and can be applied to account for the effect of the particle size distribution on erosion prediction for gases and liquids.

scholarly journals Analysis of Equation of State for Carbon Nanotubes

2013 ◽  
Vol 2013 ◽  
pp. 1-5 ◽  
Author(s):  
Jeewan Chandra ◽  
Pooja Kapri Bhatt ◽  
Kuldeep Kholiya
Keyword(s):  
Experimental Data ◽  
Carbon Nanotubes ◽  
Thermal Expansion ◽  
Carbon Nanotube ◽  
Equation Of State ◽  
Compression Behavior ◽  
Nanotube Bundles ◽  
The Individual

Compression behavior of carbon nanotube bundles and individual carbon nanotubes within the bundle has been studied by using the Suzuki, Shanker, and usual Tait formulations. It is found that the Suzuki formulation is not capable of explaining the compression behavior of nanomaterials. Shanker formulation slightly improves the results obtained by the Suzuki formulation, but only usual Tait’s equation (UTE) of state gives results in agreement to the experimental data. The present study reveals that the product of bulk modules and the coefficient of volume thermal expansion remain constant for carbon nanotubes. It has also been found that the individual carbon nanotubes are less compressible than bundles of carbon nanotubes.

scholarly journals Particle Size Distribution of E-Cigarette Aerosols and the Relationship to Cambridge Filter Pad Collection Efficiency

2015 ◽  
Vol 26 (4) ◽  
Author(s):  
Steven L. Alderman ◽  
Chen Song ◽  
Serban C. Moldoveanu ◽  
Stephen K. Cole
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Particle Size Distribution ◽  
Size Distribution ◽  
Propylene Glycol ◽  
Collection Efficiency ◽  
Transmission Measurement ◽  
Average Particle ◽  
Electrical Mobility ◽  
Total Particulate Matter

AbstractThe relatively volatile nature of the particulate matter fraction of e-cigarette aerosols presents an experimental challenge with regard to particle size distribution measure-ments. This is particularly true for instruments requiring a high degree of aerosol dilution. This was illustrated in a previous study, where average particle diameters in the 10-50 nm range were determined by a high-dilution, electrical mobility method. Total particulate matter (TPM) masses calculated based on those diameters were orders of magnitude smaller than gravimetrically determined TPM. This discrepancy was believed to result from almost complete particle evaporation at the dilution levels of the electrical mobility analysis. The same study described a spectral transmission measurement of e-cigarette particle size in an undiluted state, and reported particles from 210-380 nm count median diameter. Observed particle number concentrations were in the 10Described here is a study in which e-cigarette aerosols were collected on Cambridge filters with adsorbent traps placed downstream in an effort to capture any material passing through the filter. Amounts of glycerin, propylene glycol, nicotine, and water were quantified on the filter and downstream trap. Glycerin, propylene glycol, and nicotine were effciently captured (> 98%) by the upstream Cambridge filter, and a correlation was observed between filtration efficiency and the partial vapor pressure of each component. The present analysis was largely inconclusive with regard to filter efficiency and particle-vapor partitioning of water. [Beitr. Tabakforsch. Int. 26 (2014) 183-190]

Thermodynamics of Bidisperse Ferrofluids in Zero External Magnetic Field: Theory and Simulations

2015 ◽  
Vol 233-234 ◽  
pp. 331-334
Author(s):  
Anna Yu. Solovyova ◽  
Ekaterina A. Elfimova
Keyword(s):  
Magnetic Field ◽  
Field Theory ◽  
Free Energy ◽  
External Magnetic Field ◽  
Volume Concentration ◽  
Helmholtz Free Energy ◽  
Hard Spheres ◽  
Particle Volume ◽  
Simulation Data ◽  
Theoretical Predictions

The thermodynamic properties of a ferrofluid modeled by a bidisperse system of dipolar hard spheres in the absence of external magnetic field are investigated using theory and simulations. The theory is based on the virial expansion of the Helmholtz free energy in terms of particle volume concentration. Comparison between the theoretical predictions and simulation data shows a great agreement of the results.

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