The results of proposed models were compared to 23 well-known theoretical and empirical models. Islam, R.; Shabani, B. please go to the Copyright Clearance Center request page. The present work shows an innovative frame saw machine to cut granite, the eccentric hinge guide mechanism is introduced into the machine. It was observed that the position of the thermocouples can result in an under-estimation of the Nusselt number. Because of the poor electrical conductivity of the -SiC particles compared to the base ethylene glycol and propylene glycols ( p < < bf), case (1) therefore holds accordingly. 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%. 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. Comparisons with data from literature confirmed the validity and the suitability of the nanoflash technique applied to thermal conductivity evaluation. The different weight ratios of propylene glycol/water mixtures are used as base. Webconductivity. The values of Ck and C for all the volume concentrations and, The purchased UDD powders were successfully treated using strong acids, dry powders of salt and sucrose to remove carbon impurities. However, experimental studies that jointly explore the physical properties of hybrids and the corresponding mono nanofluids are missing. These plates are to be used in a proposed compact (thin and light-weight) solar thermal flat plate collector (FPC). The heat transfer capability of these single phase heat transfer fluids is limited because of its poor thermal conductivity. V.C.1 Complex Coolant Fluid for PEM Fuel Cells - Energy Propylene Glycol Ethers New thermal conductivity and viscosity correlations have been developed based on the experimental data. Measuring glycol concentrations by electrical conductivity is not recommended, especially in process systems, heat exchangers, etc. The quality of [30] also prepared 20:80%, 40:60% PG/W based Fe3O4 nanofluids and estimated thermal conductivity and viscosity experimentally. 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. PGI is a colorless, water soluble, hygroscopic liquid with a characteristic glycol odor, medium viscosity, low vapor Electrical E-mail: The Wilson plot method is used to analyze the helical coil side heat transfer coefficients. BNNBs exhibit high thermal conductivity due to efficient phonon transfer and they are electrical insulators owing to their wide bandgap. 8 . The formation of carboxyl (COOH) groups on the surface of ND particles was analyzed by FTIR spectrum. Naik and Sundar [28] prepared 30:70% PG/W based CuO nanofluid and estimated thermal conductivity and viscosity experimentally. The thermal conductivity results here reported can be compared with those previously published by Sundar et al. On the other hand preparation of propylene glycol/water (PG/W) based nanofluids and estimation of thermal properties is also important before use in heat transfer equipments, because these PG/W fluids are also used as engine coolants for automobile radiators. These values are significantly larger than that of the marble frame saw. 0000115846 00000 n This paper investigates the significance of some micro scaling effects in micro-channel absorber plates. Water-Glycol mixture measurement | Baker Hughes They obtained increases of 10.4% and 9.9% for 0.5 vol% concentration of Fe3O4 [14] and 1 vol% concentration of nanodiamonds [15] at 293.15 K, respectively. 0000113197 00000 n How about a secondary heat exchanger, i.e primary steam/water heats intermediate water. Intemediate water is pumped to a secondary heat exchanger w Branson et al. 0000003035 00000 n Energy . WebBNNBs exhibit high thermal conductivity due to efficient phonon transfer and they are electrical insulators owing to their wide bandgap. 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. 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. %PDF-1.6 % 0000000918 00000 n A. O. Maselugbo, B. L. Sadiku and J. R. Alston, 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). * 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. Xu X, Choi SUS. %%EOF Experimental research was done on the heat transfer, entropy generation, and exergy efficiency of ethylene glycol (EG) based nanodiamond (ND) nanofluids flowing in a circular tube. Read more about how to correctly acknowledge RSC content. The functional groups on the treated UDD powders were analyzed by FTIR. 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. Thereby, nanofluids have proven to be useful in applications, especially electronic cooling, where increasing thermal properties and avoiding electrical conductivity are vital. [17] prepared mineral oil based ND nanofluids and obtained thermal conductivity enhancement of 70% at 0.1wt.%. If you are an author contributing to an RSC publication, you do not need to request permission 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. For 1.0% vol. Scaling effects such as viscous dissipation and entrance effects had insignificant impact on the measured average Nusselt number. [34] for Al2O3/PG and TiO2/PG nanofluids. Ghazvini et al. The findings suggest that BNNBs have great potential for use as thermally conductive nanoparticles in nanofluids for various heat transfer applications. However, conjugate heat transfer and measurement uncertainties were significant. WebMaintains low electrical conductivity Uses proprietary non-ionic corrosion inhibitor formulation with years of research Can be used with Formulation: Propylene Glycol, WebThermal conductivities for some common liquids at temperature 300 K (26.8 oC, 80.3 oF): 1 W/(m K) = 1 W/(m oC) = 0.85984 kcal/(h m oC) = 0.5779 Btu/(ft h oF) = 0.048 Btu/(in h conductivity [19] obtained viscosity enhancement of 80% for midel oil based ND nanofluids at 3.0wt.%. The thermal conductivity of single phase heat transfer fluids may be enhanced by dispersing small quantity of solid particles. In this study, more than 3200 data of thermal conductivity of nanofluids were collected from literature to develop simple-to-use and accurate correlations for predicting relative thermal conductivity of nanofluids. 115-123, International Communications in Heat and Mass Transfer, Volume 76, 2016, pp. [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. Prasher et al. [27] analysis if the value of C/Ck<4 then the nanofluid is heat transfer beneficial fluid. Electrical conductivity measurements of nanofluids and - PubMed 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. 0000088556 00000 n Yeganeh et al. The thermal conductivity of 0.1vol% of N-CQDs nanofluid increased by 43.21% at 50C compared to the base fluid. Investigation on the Electrical Conductivity of Nanofluids offer many opportunities to enhance the efficiency of thermal systems by improving the thermal properties of the host fluids. The Choi [1] and his team developed nanofluids (fluids contain nanometer size particles) and obtained higher thermal conductivity compared to base fluids. electrical The PG/W nanofluids are prepared with acid treated ND particles. The frictional exergy destruction is found to contribute together with heat transfer exergy destruction to the total entropy of the SCHE system. The B4C mono nanofluid shows the highest improvements of thermal conductivity (6.0%) and electrical conductivity (70 times higher), but also the highest viscosity increases (5154%). conductivity of propylene glycol Sundar et al. The viscosity of N-CQDs nanofluid behaves as a Newtonian fluid. [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. Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, USA 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. 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 PureCool LEC-PG Low Conductivity Heat Transfer Fluid Download : Download high-res image (216KB)Download : Download full-size image. 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. During the preparation of UDD powders, igniter is used in the detonation process which causes metal and carbon impurities and those are aggregates or attached to the outer surface of the ND particles. 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. [12] also used acid mixtures of perchloric acid, nitric acid and hydrochloric acid (based on the procedure of Jang and Xu [13]) for the removal of carbon impurities from the UDD powders and prepared stable ND nanofluids in the base fluid of 55:45% ethylene glycol/water mixture and observed thermal conductivity enhancement of 18% at 2.0vol.%. The reason for the agglomeration of UDD powders in the base fluid is due to the presence of carbon impurities. The purification of UDD powders is important for achieving good stable nanofluids. 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 0000073108 00000 n WebConductivity is a measure of the ability of water to pass an electrical current. 0000087804 00000 n An estimation of the optimal supplied energy and time for sonication was suggested, while temperature and volumetric concentration effects on thermal conductivity are evaluated by measurements. DOWFROSTfluid has an operating There are different methods to purify the UDD powders. To request permission to reproduce material from this article, please go to the 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 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. The present findings are consistent with those of Palabiyik et al. 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. 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. 0000002868 00000 n Effects of working temperature on thermo-physical properties and forced convection heat transfer of TiO 2 nanofluids in waterEthylene glycol mixture. 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. Sundar et al. DOW Propylene Glycol, Industrial Grade The instrument is based on transient plane source (TPS) technique and is widely used for thermal conductivity measurement. Nanodiamondwater nanofluids were prepared and estimated the thermal conductivity, viscosity and also estimated their potential use in heat transfer applications. Electrical and Thermal Conductivities of 50/50 Water Diamond circular saws and diamond wire saws present some technological limits, and the marble frame saw cannot process granite by now. Experiments were performed to study the transient heat transfer characteristics of probe-ultrasonicated, surfactant-free, ZnOpropylene glycol (ZnOPG) nanofluids under constant heat flux and constant bath temperature conditions. conductivity 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. 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. Propylene glycol When compared to Propylene glycolwater (50:50) along with Propylene glycolwater (50:50) dispersed with 0.25% Graphene, it is clear from Fig. The specific heat capacity decreases with increasing nanofluid loading. [27] prepared PG based Al2O3 nanofluids and estimated viscosity experimentally and proposed viscosity model. Table 8-3-1 - Properties of mixture Water/Glycol - CERN Corresponding authors, a 209 0 obj<>stream 180 0 obj <> endobj 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 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). The local Nusselt number was observed to vary axially despite satisfying the criteria for neglecting entrance effects; this variation increased with the Graetz number. 2 shows the IR spectra of UDD powders, acid treated, salt and sucrose milled samples. This paper reviews and summarizes the experimental values of the physical and thermal properties, including an appropriate focus on the thermal conductivity enhancement, of nanodiamond-nanofluid systems found in the literature as well as different techniques for thermal conductivity measurement. The effect of BNNB concentration in carrier fluids on nanofluid thermal conductivity was investigated by introducing BNNBs into ethylene glycol-water and propylene glycol-water mixtures at 010 wt%. [27] analysis.knfkbf=1+Cknfbf=1+Cwhere, is the volume concentration, Ck and C are the thermal conductivity and viscosity enhancement coefficients. The carbon impurities present in the UDD powders is removed with strong acid treatment, dry salt and dry sucrose to make them into single ND crystals. The inadequacy of the widely used VogelTammannFulcher or WilliamsLandelFerry equations to describe the temperature variation of the vacuum [14,15] for mono nanofluids based on the same base fluid, propylene glycol:water 20:80 wt%. 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. 0000125049 00000 n The NTU of SCHE is improved only by 2% over that of the base fluid at the flow rate of 6 lit/min because of the limited improvement of the overall heat transfer coefficient. In the heat exchanger, the hot fluid passes through the shell side and the cold fluid (nanofluid) passes through the helical coil side. Pressure and temperature variation of the electrical conductivity of 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. The starting product, MICRONAL 5428 X, which contains about 43% microencapsulated paraffin with a transformation temperature of 28 0000102258 00000 n 0000088822 00000 n After cycling at 25 and 80 C, LiGe alloy was formed at the Li/LAGP interface as investigated by synchrotron high energy X-ray Diffraction (HEXRD) spectra (Figure 3b ).
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