The synthesized environmentally friendly N-doped carbon quantum dots nanoparticles (N-CQDs) had a uniform particle size distribution, with particle sizes concentrated between 2 and 2.5nm. 0000000016 00000 n
Scaling effects such as viscous dissipation and entrance effects had insignificant impact on the measured average Nusselt number. Yeganeh et al. 0000087804 00000 n
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WebPropylene Glycol Methyl Ether (PM; CAS No. From the Prasher et al. This paper presents results of experimental investigation into dielectric properties of silicon oxide lignin (SiO 2-L) particles dispersed with various mass fractions in ethylene glycol (EG).Measurements were conducted at a controlled temperature, which was changed from 298.15 to 333.15 K with an accuracy of 0.5 and 0.2 K for dielectric Xie et al. 0000002868 00000 n
The earlier works reveals the preparation, estimation of thermal conductivity and viscosity of EG/W mixture based Al2O3, CuO, ZnO and Fe3O4 nanofluids. The carbon impurities present in the UDD powders have been removed using mixture of H2SO4 and HNO3 [5], [6], [7], [8], [9]. New thermal conductivity and viscosity correlations have been developed based on the experimental data. The preparation of ND based nanofluids and their thermal properties are given below. The density, isobaric heat capacity, and thermal conductivity of the nanofluids are determined by the oscillating U-tube, differential scanning calorimetry, and transient hot wire methods, respectively. The optimized method for purifying the UDD powders is established. The fluid is colorless (water white). The thermal conductivity of 0.1vol% of N-CQDs nanofluid increased by 43.21% at 50C compared to the base fluid. Common uses: antifreeze/heat transfer fluid. The stable ND nanofluids were prepared by considering 60:40% water+ethylene glycol (weight percentage) mixture as base fluid and the experiments were performed at particle loadings ranging from 0.2% to 1.0% and the Reynolds number ranging from 900 to 4800, respectively. Correlations for the thermo-physical properties of the nanofluid were developed. WebIn this study the electrical conductivity of aluminum oxide (Al2O3), silicon dioxide (SiO2) and zinc oxide (ZnO) nanoparticles dispersed in propylene glycol and water mixture The reason for the agglomeration of UDD powders in the base fluid is due to the presence of carbon impurities. Using propylene glycol (PG) without any dispersants as a salt-free medium, we measure the electrical conductivities of 20, 40, and 60 nm diameter ZnO nanoparticle dispersions up to 7% volume fraction, applying Ohshima's model to determine the limiting ionic conductance of the system. Nanofluid preparation and characterization Nanofluid preparation Due to its exceptional thermal, mechanical and electrical properties, diamond has attracted attention for use as a nanoparticle in fluids. Nanodiamond (ND) nanoparticles of primary particle size of 510nm can be produced in large quantity by using commercially available ultra-dispersed diamond (UDD) powders. Conductivity is also affected by temperature: the warmer the water, the higher the conductivity. The study also investigated the dispersion stability of BNNBs in different solvents using Hansen Solubility Parameters, revealing that propylene glycol mixtures demonstrated better long-term stability compared to ethylene glycol mixtures. There are different methods to purify the UDD powders. Branson et al.
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Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA. Measuring glycol concentrations by electrical conductivity is not recommended, especially in process systems, heat exchangers, etc. The quality of For reliability, Electrical conductivity of aqueous Propylene glycol (PG/W-30/70) is determined (30EG/70W) as a for three times and the same is compared with A detailed procedure is presented for the implementation and evaluation, by Nano-Flash Method, of thermal conductivity of nanofluids with water as base fluid and at different volume concentrations of Al2O3. These values are significantly larger than that of the marble frame saw. 40-48, Applied Thermal Engineering, Volume 90, 2015, pp. The rheological behaviour is investigated through rotational rheometry. The hot fluid volume flow rate was fixed to 1 lit/min, whereas, the cold fluid (nanofluid) volume flow rate was varied from 2 to 6 lit/min. DOWFROSTfluid has an operating The strong acid treatment on UDD powders, the carboxyl groups are formed on the surface of ND particles, which can be clearly observed in the IR spectra (red line). ScienceDirect is a registered trademark of Elsevier B.V. ScienceDirect is a registered trademark of Elsevier B.V. 2023, Thermal Science and Engineering Progress, 2023, International Journal of Thermal Sciences, 2022, International Communications in Heat and Mass Transfer, Diamond and Related Materials, Volume 69, 2016, pp. 0000002335 00000 n
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The X-ray powder diffraction (XRD), transmission electron microscope (TEM) and Raman spectra was also performed on acid treated ND particles. Web9.9 Liquid Water Interfacial Tension: Not pertinent 9.10 Vapor (Gas) Specific Gravity: Not pertinent 9.11 Ratio of Specific Heats of Vapor (Gas): 1.073 9.12 Latent Heat of Vaporization: 306 Btu/lb = 170 cal/g = 7.12 X 105J/kg 9.13 Heat of Combustion: 10,310 Btu/lb = 5,728 cal/g = 239.8 X 105J/kg 9.14 Heat of Decomposition: Not pertinent Another method for removing the carbon impurities from the UDD powders is with dry salt or dry sucrose [10]. However, those results have not been collectively compared or discussed.
[19] obtained viscosity enhancement of 80% for midel oil based ND nanofluids at 3.0wt.%. FPx[[cu/Ajl22jw+x{5DD93o9$C y6q`xTu/~:'KY'Nf700zGRb9 cyI/
dk'Cw JO|i%H_o]*2?h1tz{]uhD5:h;)[.2sQvW |ZHcv7Qcr9]Ee5c w?a%2b5XATC3{d^Tzt h-!T`EH|}'EPj:]vRFl_/
uoDG0x5zUK;EI[".WzVkE=*j\2U]O sh`5 The thermal conductivity and viscosity of ND nanofluids were investigated experimentally, whereas the density and specific heat were estimated theoretically. [14,15] for mono nanofluids based on the same base fluid, propylene glycol:water 20:80 wt%. The eccentric hinge guide mechanism facilitates the formation of both matrix tails on the segments and a group of more new micro cutting edges, which improve diamond stability as well as self-sharpening. Increasing the concentration of the nanofluid beyond 1.0vol% shows a little improvement in the effectiveness of the heat exchanger. WebPropylene glycol is a colourless liquid that is relatively viscous, has no odour, and tastes slightly sweet. 245-255, Applied Thermal Engineering, Volume 91, 2015, pp. WebIn this work, mono B 4 C and TiB 2 and hybrid TiB 2:B 4 C nanoadditives are used for the first time to design nanofluids based on propylene glycol:water 20:80 wt%. Substance and % by volume in mixture: Minimal working temperature [o C] Vajjha and Das [24] also prepared 60:40% (weight ratio) of EG/W based Al2O3, CuO and ZnO nanofluids and measured thermal conductivity up to 10.0vol.%. Under constant heat flux conditions, ZnOPG nanofluids exhibited linear increase in heat removal rates with increasing nanoparticle concentration. Based on the results, the thermal conductivity enhancements are 18.8%, 16.8% and 14.1% at 1.0vol.% of 20:80%, 40:60% and 60:40% PG/W based nanofluids. The Choi [1] and his team developed nanofluids (fluids contain nanometer size particles) and obtained higher thermal conductivity compared to base fluids. Thermal conductivity of nanoparticle-fluid mixture. However, experimental studies that jointly explore the physical properties of hybrids and the corresponding mono nanofluids are missing. We are continuing our optimization to bring this level down by an order of magnitude (which is accepted by almost all the fuel cell manufacturers). Because dissolved salts and other inorganic chemicals conduct electrical current, conductivity increases as salinity increases. WebMaintains low electrical conductivity Uses proprietary non-ionic corrosion inhibitor formulation with years of research Can be used with Formulation: Propylene Glycol, Based on the above methods the acid treatment method is more effective compared to other salt and sucrose methods. The frictional exergy destruction is found to contribute together with heat transfer exergy destruction to the total entropy of the SCHE system. 1123-1135, Experimental thermal conductivity and viscosity of nanodiamond-based propylene glycol and water mixtures, https://doi.org/10.1016/j.diamond.2016.07.007, nm can be produced in large quantity by using commercially available ultra-dispersed diamond (UDD) powders.
BNNBs exhibit high thermal conductivity due to efficient phonon transfer and they are electrical insulators owing to their wide bandgap. In the heat exchanger, the hot fluid passes through the shell side and the cold fluid (nanofluid) passes through the helical coil side. Thus, the new prototype machine is suitable for sawing granite. The ultra-sonication technique was employed for preparing the mixture and results showed that the stability and thermal conductivity enhancements of Al2O3H2O nanofluids are highly dependent on sonication time and the energy supplied to the fluid for its preparation. Tyler et al. This study recommends that the volume concentration of Fe3O4/60:40%W+EG nanofluid should not exceed volume concentration of 1.0% because the added benefit of working with concentrations higher than 1.0vol% may not outweigh the added cost and complexities of the nanofluid. The functional groups on the treated UDD powders were analyzed by FTIR. 0000102258 00000 n
Corresponding authors, a
WebUsing the results for propylene glycol/water with corrosion inhibitor and nanoparticles, for over 3,000 hours of operation, the conductivity of the solution would have gone up to about 27 mS/cm-hr. Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, USA
The present work focused on the preparation of different weight ratio of PG/W (20:80%, 40:60% and 60:40%) mixture based ND nanofluids and the estimation of thermal conductivity and viscosity experimentally at different particle concentrations and temperatures. model and the Mouromtseff number were used to study the heat transfer capability of ND nanofluid under laminar and turbulent flow conditions. please go to the Copyright Clearance Center request page. The other chemicals such as sulfuric acid (H2SO4), nitric acid (HNO3), sodium chloride (NaCl), sucrose (C12H22O11) and propylene glycol (C3H8O2) were purchased from Sigma-Aldrich Chemicals, USA. Interactions between spherical and sheet-like nanoparticles explain this behaviour. The specific heat capacity decreases with increasing nanofluid loading. The results show that the contact area between the blade and granite is not following a straight line, and the time required for stone sawing is only one half of the full sawing cycle. [14] also used strong acids of H2SO4 and HNO3 in the molar ratio of 3:1 for the purification of UDD powders and prepared 20:80%, 40:60% and 60:40% ethylene glycol/water mixture based ND nanofluids and estimated both thermal conductivity and viscosity experimentally. Since water is seen as the golden standard in thermal conductivity, higher concentrations of ethylene glycol in a water solution will cause heat to pass through it slower, therefore, the lower the amount of ethylene glycol in the mixture, the more efficient it is at conducting heat. to access the full features of the site or access our, Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, USA, Joint School of Nanoscience and Nanoengineering, University of North Carolina at Greensboro, Greensboro, NC 27401, USA. This study investigates theoretically and experimentally the electrical and thermal conductivities of 50/50 water-ethylene glycol based TiO 2 nanofluids with Theoretical approach is used to identify the heat transfer benefits of the prepared propylene glycol/water based ND nanofluids in laminar and turbulent flow conditions using the thermal properties. The X-ray powder diffraction (XRD), transmission, C, respectively compared to their respective base fluids. in a third-party publication (excluding your thesis/dissertation for which permission is not required)
To create stable nanofluids, the ND nanoparticles are ultrasonically agitated with EG for 4h. At a constant heat flux of q=9099W/m2, experiments were carried out in a laminar flow with Reynolds numbers ranging from 264.4 to 2194.4. [16] prepared 20% of water and 50% of engine oil based ND nanofluids and obtained thermal conductivity enhancement of 25% at 1.0wt.% Taha-Tijerina et al. The thermal entropy generation is decreased by 31.78% and the frictional entropy generation is raised by 22.50% over the basic fluid data at 1.0% and Reynolds number of 1454.4. 180 30
and diagrams provided correct acknowledgement is given.
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Results show, at 1.0vol% and the Reynolds number of 2702, the heat transfer coefficient and Nusselt number is increased by 36.05%, and 27.47%, respectively, over the base fluid. The low freezing point of water (below 0C) may be achieved by adding different ratios of ethylene glycol or propylene glycol, so that the EG/W or PG/W fluid can operate up to 50C without any difficult [22]. Chemical co-precipitation was used for the synthesis of large quantity of Fe3O4 nanoparticles with an average particle size of 11.42nm. In addition, the models for estimating the viscosity and thermal conductivity of N-CQDs nanofluids are proposed, respectively. However, the penalty in friction factor and pressure drop is 17.28% and 14.24% under the same Reynolds number and 1.0vol% nanofluid over the base fluid. The theoretical models of Maxwell and Einstein have failed to estimate the thermal conductivity and viscosity of nanofluids as a function of temperature. This study investigates theoretically and experimentally the electrical and thermal conductivities of 50/50 water-ethylene glycol based TiO 2 nanofluids with nanoparticle concentrations in the range of 0.05-0.5 vol%. The exergy efficiency of the SCHE can be increased by 21% using 1.0vol% of nanofluid, but the improvement becomes modest as the volume concentration is increased further. startxref
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An enhancement of 4.24% in heat transfer rate was observed with 2vol.% ZnOPG nanofluid. [17] prepared mineral oil based ND nanofluids and obtained thermal conductivity enhancement of 70% at 0.1wt.%. The ultra-dispersed diamond (UDD) powders were purchased from International Technology Centre, USA (http://www.itc-inc.org) with the following specifications: 98% purity, 510nm particle core size, cubic shape, grey color, 300400m2/g specific surface area. The dataset includes 13 different nanofluids with temperature from 30.00 to 149.15C, particle size from 5.00 to 150.00nm, particle thermal conductivity from 1.20 to 1000.00W/mk, particle volume fractions from 0.01 to11.22%, and base fluid thermal conductivity from 0.11 to 0.69W/mk. The purchased UDD powders treated with strong acid treatment, dry salt and dry sucrose to make them into single ND-crystals. provided correct acknowledgement is given. The commercially available ultra-dispersed diamond (UDD) powders of an average size of 0.12.0m have been used by Dolmatov [2] for the preparation of ND nanofluids, but he faced serious agglomeration problem with UDD powders in the base fluid. [27] prepared PG based Al2O3 nanofluids and estimated viscosity experimentally and proposed viscosity model. BNNBs are allotrope composites composed of boron nitride nanotube cores with walls decorated with attached hexagonal boron nitride crystals, creating a jagged morphology that facilitates the formation of a connected network and contributes to the enhancement of thermal conductivity in nanofluids. The effect of various factors on the thermal-physical properties of diamond nanofluids is also reviewed, and the stability and viscosity of diamond nanofluids are tabulated and compared. 34590-94-8 isomeric mixture and 20324-32-7 major isomer) PM and PMA were reviewed at SIAM 11 and DPM was reviewed at SIAM 12. Theoretical approach is used to identify the heat transfer benefits of the prepared propylene glycol/water based ND nanofluids in laminar and turbulent flow conditions using the, Portuguese Science and Technology Foundation, Investigations of thermal conductivity and viscosity of nanofluids, Viscosity of alumina nanoparticles dispersed in car engine coolant, Thermal conductivity of ethylene glycol and water mixture based Fe, Experimental determination of thermal conductivity of three nanofluids and development of new correlations, Numerical study of turbulent flow and heat transfer characteristics of nanofluids considering variable properties, Experimental investigation on the thermal transport properties of ethylene glycol based nanofluids containing low volume concentration diamond nanoparticles, Thermal transport properties of diamond-based nanofluids and nanocomposites, Volume fraction and temperature variations of the effective thermal conductivity of nanodiamond fluids in deionized water, Enhanced thermal properties of nanodiamond nanofluids, Increase of nanodiamond crystal size by selective oxidation, Experimental investigation of heat transfer and effectiveness of employing water and ethylene glycol mixture based Fe
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