The authors would like to acknowledge the Portuguese Science and Technology Foundation (FCT) for the funding of the present research work through the grant no: PTDC/EME-MFE/105031/2008 (ACMS) and UID/EMS/00481/2013 (TEMA/DEM). Further to cme's statement, the injection pump for the feed can be alarmed to allow the user know that there may be a system leak. See the follo 0000003320 00000 n [18] observed thermal conductivity enhancements of 7.2% and 9.8% for water based ND nanofluids at 3.0vol.% at temperatures of 30C and 50C, respectively. An enhancement of thermal conductivity with respect to temperature and volumetric concentration is found, as expected. . 8 . The results showed that the Turbiscan stability index of N-CQDs nanofluid was about 1.5 and the T value fluctuated within 0.5%, showing excellent stability. 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. The specific heat capacity decreases with increasing nanofluid loading. If you are an author contributing to an RSC publication, you do not need to request permission There are different methods to purify the UDD powders. 0000003035 00000 n Xie et al. Correlations for the thermo-physical properties of the nanofluid were developed. A shell and helically coil heat exchanger (SCHE) is used to experimentally investigate the performance of 60% water and 40% ethylene glycol mixture based Fe3O4 nanofluid as a coolant. We use cookies to help provide and enhance our service and tailor content and ads. WebPropylene Glycol Methyl Ether (PM; CAS No. Fig. The functional groups on the treated UDD powders were analyzed by FTIR. It was observed that the position of the thermocouples can result in an under-estimation of the Nusselt number. New thermal conductivity and viscosity correlations have been developed based on the experimental data. The viscosity of N-CQDs nanofluid behaves as a Newtonian fluid. Hybrid nanofluids aim to further improve the characteristics of mono nanofluids. WebDOWFROSTfluid is a formulation of 95.5 percent propylene glycol, dipotassium phosphate and water. 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. BNNBs exhibit high thermal conductivity due to efficient phonon transfer and they are electrical insulators owing to their wide bandgap. [17] prepared mineral oil based ND nanofluids and obtained thermal conductivity enhancement of 70% at 0.1wt.%. 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. 499-508, Energy Conversion and Management, Volume 96, 2015, pp. For 1.0% and a Reynolds number of 1454.4, the thermal performance factor is increased by 1.194-times above the basic fluid. 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 Reynolds numbers were in the range 10100 and fluid inlet temperatures ranged from 5 to 40C. WebPGI is a distilled product with a purity specification of minimum 99.5% and is available from The Dow Chemical Company in drum, IBC and bulk quantities. 0000087804 00000 n 180 30 The fluid is colorless (water white). One of the authors (L.S.S.) 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. The earlier works reveal the preparation, estimation of thermal conductivity and viscosity of water, ethylene glycol, mineral oil and midel oil based ND nanofluids. Prediction of electrical conductivity of TiO 2 water and ethylene glycol-based nanofluids for cooling application in low temperature PEM fuel cells. <]>> 0000113197 00000 n The electrical conductivity of glycol mixtures within the range of The thermal conductivity and viscosity of ND nanofluids were investigated experimentally, whereas the density and specific heat were estimated theoretically. Among all the carbon materials ND particles creates great interest because of their superior hardness, thermal conductivity, i.e. New friction factor and Nusselt number equations were created. Webviscosity, a relatively high specific heat and thermal conductivity, as well as good mixing with water and alcohols cause the ethylene glycol to be widely used in practice [13]. The frictional exergy destruction is found to contribute together with heat transfer exergy destruction to the total entropy of the SCHE system. This paper investigates the significance of some micro scaling effects in micro-channel absorber plates. The preparation of ND based nanofluids and their thermal properties are given below. This study reports a nanofluid that achieves long-term stability without any additives. The UDD powders can be treated with strong acids such as HNO3, mixture of H2SO4/HNO3, K2Cr2O7 in H2SO4, KOH/KNO3 to remove the carbon impurities [3], [4]. Please enable JavaScript xref These values are significantly larger than that of the marble frame saw. Read more about how to correctly acknowledge RSC content. 0000033853 00000 n About 26% increase in coolant side heat transfer coefficient was obtained with 2vol.% ZnOPG nanofluid under constant bath temperature condition which could be attributed to thermal conductivity enhancement as well as improved natural convection due to viscosity reduction. [27] analysis.knfkbf=1+Cknfbf=1+Cwhere, is the volume concentration, Ck and C are the thermal conductivity and viscosity enhancement coefficients. Absolute deviations lower than 1.5% were obtained between the experimental and predicted data using the aforementioned nanopowder thermal conductivities, as can be observed in Fig. p^h72n* 8pW&.=rfeK&=d_">!f4-6%)|Z>,^R :qz*jn88H1 Z'2P?[-ik,2T0!L The purchased ultradispersed diamond (UDD) nanoparticles were treated with strong acid solution to make it into almost single nano-diamond (ND) particles. The results showed that BNNBs enhanced thermal conductivity of carrier fluids up to 45%, and the enhancement was proportional to the concentration of BNNBs in the carrier fluid. Ghazvini et al. The UDD powders contains large quantity of carbon impurities, which can be removed using strong acid treatment, dry salt and dry sucrose to make UDD powders into single ND particles. In this work, mono B4C and TiB2 and hybrid TiB2:B4C nanoadditives are used for the first time to design nanofluids based on propylene glycol:water 20:80wt%. Chemical treatment was used to make ND nanoparticles with an average size of 5.42nm. From the IR spectra, the UDD powders contain some functional groups of H, OH, COOH were clearly observed but the intensity is very low (black line). How about a secondary heat exchanger, i.e primary steam/water heats intermediate water. Intemediate water is pumped to a secondary heat exchanger w The overall heat transfer coefficient and nanofluid-side heat transfer coefficient under constant bath temperature condition were found to increase with increasing nanoparticle volume concentration. 0000060250 00000 n 0000002101 00000 n Similarly, the viscosity enhancements are 1.55-times, 1.50-times and 1.66-times for the same 1.0vol.% of 20:80%, 40:60% and 60:40% PG/W based nanofluids at a temperature of 60C, respectively compared to their respective base fluids. 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). Another method for removing the carbon impurities from the UDD powders is with dry salt or dry sucrose [10]. Yu et al. Similarly, at 1.0vol% and Reynolds number of 2702, the thermal entropy generation is dropped by 38.12%, frictional entropy generation is raised by 12.86%, exergy efficiency is enhanced by 36.48% and thermal performance factor is augmented by 1.2094 times over the base fluid. The local Nusselt number was observed to vary axially despite satisfying the criteria for neglecting entrance effects; this variation increased with the Graetz number. 0000088822 00000 n In addition, it was found that the proposed models could capture the physically expected trends with variation of temperature, size of nanoparticles, and volume fraction. 0000002335 00000 n 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. They also observed the formation of carboxyl groups on the surface of ND particles based on the FTIR analysis. 0 Glycol soutions are fed (topped-off) buy a pumped glycol feeder available by JL wingert, armstrong, etc Heat exchanger tubes are .035" wall I've ne 40-48, Applied Thermal Engineering, Volume 90, 2015, pp. 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. The results are beneficial for the design and operation of micro-channel absorber plates. Webconductivity. would like to thank FCT for his post-doctoral research grant: SFRH/BPD/79104/2011. Here, we perform electrical characterizations of propylene glycol-based ZnO nanofluids with volume fractions as high as 7%, measuring up to a 100-fold increase in electrical conductivity over the base fluid. Annual production of propylene glycol in The single phase heat transfer fluids such as water (W), ethylene glycol (EG), propylene glycol (PG) and engine oil (EO) are primarily used in may industrial applications, among others, power, chemical and food industries. 0000102258 00000 n provided correct acknowledgement is given. <50C [21]. 0000133274 00000 n The stable PG/W mixture based ND nanofluids were prepared by dispersing ND acid treated, The nanodiamond (ND) particles were produced using commercially available ultra-dispersed diamond (UDD) powders. I always eqip the system with a 2" hose connection with check valve so the contractor can use a pump to fill the system those glycol feeders The instrument is based on transient plane source (TPS) technique and is widely used for thermal conductivity measurement. The theoretical models of Maxwell and Einstein have failed to estimate the thermal conductivity and viscosity of nanofluids as a function of temperature. New thermal conductivity and viscosity correlations were proposed by including the effects of volume concentrations and temperatures. The as-obtained LAGP thin film also possessed a high ionic conductivity of 2 10 5 S cm 1 at 25 C and a low electronic conductivity value of 1.1 10 9 S cm 1. MEG (Mono Ethylene Glycol) or C2H6O2. * In addition, the models for estimating the viscosity and thermal conductivity of N-CQDs nanofluids are proposed, respectively. The X-ray powder diffraction (XRD), transmission electron microscope (TEM) and Raman spectra was also performed on acid treated ND particles. [15] observed thermal conductivity enhancement of 12% at 0.9vol.% of nanodiamond (ND)-poly (glycidol) polymer brush/EG nanofluids, similarly observed thermal conductivity enhancement of 11% at 1.0vol.% of ND.oleic acid/mineral oil nanofluids. Properties for Dowfrost (Propylene Glycol) Electrical conductivity for 50% at 25 deg C = 2,060 micromhos/cm and 249 micromhos/cm for 50% at 0 deg C. Looks The hybrid nanofluid presents intermediate values between those of the mono nanofluids for all the properties except dynamic viscosity. The results of proposed models were compared to 23 well-known theoretical and empirical models. The Raman, TEM and XRD analysis was also performed on acid treated nanodiamond particles. Additionally, surface tension and electrical conductivity are investigated. Scaling effects such as viscous dissipation and entrance effects had insignificant impact on the measured average Nusselt number. 0000142997 00000 n 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. Interactions between spherical and sheet-like nanoparticles explain this behaviour. 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 Kole and Dey [29] prepared 50:50% PG/W based Al2O3 nanofluids and observed nanofluids obey Newtonian behaviour in the measured temperature range from 10C to 50C. Sundar et al. The relative electrical conductivity of -SiC NFs and model predictions determined at 298.15 K are compared as illustrated in Fig. The inadequacy of the widely used VogelTammannFulcher or WilliamsLandelFerry equations to describe the temperature variation of the vacuum 181-190, International Journal of Heat and Mass Transfer, Volume 129, 2019, pp. The formation of carboxyl (COOH) groups on the surface of nanodiamond was analyzed by FTIR. Conductivity is also affected by temperature: the warmer the water, the higher the conductivity. It has been shown that water is the best solar energy absorbance among four fluids including water, ethylene glycol, propylene glycol, Zeta potential is a measure of the electric potential difference between the surface of a particle and the surrounding fluid. Group method of data handling (GMDH) and gene expression programming (GEP) as two white-box powerful models were used for modeling. The peak near 1630cm1 represents the OH bending of physically adsorbed water and the hydrogen, Since the literature does not report for the thermal conductivity ratios of 20:80%, 40:60% and 60:40% PG/W nanofluids, in Fig. [34], in which the nanofluids prepared in pure PG have lower thermal conductivity enhancement than that of. The GMDH model showed a better performance compared to GEP, and could predict all data with an average absolute relative error of 2.27% in training and 2.44% in testing data set. 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. [27] model and Mouromtseff number [31] is used to study the heat transfer benefits of PG/W based ND nanofluids in laminar and turbulent flow conditions. Future research should focus on enhancing the dispersion stability of BNNB nanofluids and exploring the influence of BNNB morphology on the thermal conductivity and other thermophysical properties of nanofluids. At 1.0vol%, the thermal conductivity enhancements of 12.7% and 22.8%, at 1.0vol%, the viscosity enhancements of 1.57-times and 1.8-times were observed at temperatures of 293K and 333K compared to water data. Corresponding authors, a WebPropylene glycol is a colourless liquid that is relatively viscous, has no odour, and tastes slightly sweet. Results showed that ND nanofluids achieved higher heat transfer coefficients than the base fluid. 0000017674 00000 n 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. WebBNNBs exhibit high thermal conductivity due to efficient phonon transfer and they are electrical insulators owing to their wide bandgap. The thermal performance of the internal heat transfer fluid was an important factor affecting the heat transfer efficiency of the exchanger system. 0000087536 00000 n The optimized method for purifying the UDD powders is established. The findings suggest that BNNBs have great potential for use as thermally conductive nanoparticles in nanofluids for various heat transfer applications. Under constant heat flux conditions, ZnOPG nanofluids exhibited linear increase in heat removal rates with increasing nanoparticle concentration. The thermal conductivity and viscosity of ND nanofluids were estimated experimentally at different particle concentrations and temperatures. The earlier works reveals the preparation, estimation of thermal conductivity and viscosity of EG/W mixture based Al2O3, CuO, ZnO and Fe3O4 nanofluids. The starting product, MICRONAL 5428 X, which contains about 43% microencapsulated paraffin with a transformation temperature of 28 [14,15] for mono nanofluids based on the same base fluid, propylene glycol:water 20:80 wt%. 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. Namburu et al. Download : Download high-res image (216KB)Download : Download full-size image. Due to the different particle sizes and shapes of nanoparticles, the proposed model can better predict the thermal conductivity and viscosity of N-CQDs nanofluids compared with other empirical models. The UDD powders contains large quantity of carbon impurities, which can be removed using strong acid treatment, dry salt and dry sucrose to make UDD powders into single ND particles. 2016 Elsevier B.V. All rights reserved. From the Prasher et al. Substance and % by volume in mixture: Minimal working temperature [o C] Sundar et al. The thermodynamic, heat transfer and thermal performance factor were analyzed experimentally at different particle volume loadings of water+ethylene glycol mixture based nanodiamond (ND) nanofluids flow in a shell and helical coiled tube heat exchanger.