The formation of carboxyl (COOH) groups on the surface of nanodiamond was analyzed by FTIR. 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. 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 X-ray powder diffraction (XRD), transmission electron microscope (TEM) and Raman spectra was also performed on acid treated ND particles. Namburu et al. 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. [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. [27] prepared PG based Al2O3 nanofluids and estimated viscosity experimentally and proposed viscosity model. The rheological behaviour is investigated through rotational rheometry. 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%. Webconductivity. Drazen, you seem to have drifted from the original question. The problem is glycol in the condensate which could be fatal to the boiler. We need Sundar et al. The earlier works reveals the preparation, estimation of thermal conductivity and viscosity of PG/W mixture based Al2O3, CuO, and Fe3O4 nanofluids. 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 theoretical models of Maxwell and Einstein have failed to estimate the thermal conductivity and viscosity of nanofluids as a function of temperature. 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%). 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 electrical conductivity of glycol mixtures within the range of 180 0 obj <> endobj There are different methods to purify the UDD powders. 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. WebPropylene Glycol Methyl Ether (PM; CAS No. startxref Effects of working temperature on thermo-physical properties and forced convection heat transfer of TiO 2 nanofluids in waterEthylene glycol mixture. Energy . [30] also prepared 20:80%, 40:60% PG/W based Fe3O4 nanofluids and estimated thermal conductivity and viscosity experimentally. 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. Increasing the concentration of the nanofluid beyond 1.0vol% shows a little improvement in the effectiveness of the heat exchanger. Based on the above methods the acid treatment method is more effective compared to other salt and sucrose methods. DOWFROSTfluid has an operating For 1.0% and a Reynolds number of 1454.4, the thermal performance factor is increased by 1.194-times above the basic fluid. The findings suggest that BNNBs have great potential for use as thermally conductive nanoparticles in nanofluids for various heat transfer applications. 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 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. 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. Forced convection experiments were performed on an instrumented metal plate with micro-channels. MEG (Mono Ethylene Glycol) or C2H6O2. One of the authors (L.S.S.) [14,15] for mono nanofluids based on the same base fluid, propylene glycol:water 20:80 wt%. 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%. 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 All were assigned as low priority for further work. The earlier works reveals the preparation, estimation of thermal conductivity and viscosity of EG/W mixture based Al2O3, CuO, ZnO and Fe3O4 nanofluids. At 1.0vol% of nanofluid and a Reynolds number of 1454.4 in comparison to the base fluid, the Nusselt number and heat transfer coefficient are boosted by 29.43%, 45.01%, and a friction factor penalty of 27.59%, respectively. Ghazvini et al. 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. model and the Mouromtseff number were used to study the heat transfer capability of ND nanofluid under laminar and turbulent flow conditions. The functional groups on the treated UDD powders were analyzed by FTIR. Nanodiamondwater nanofluids were prepared and estimated the thermal conductivity, viscosity and also estimated their potential use in heat transfer applications. 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. Comparisons with data from literature confirmed the validity and the suitability of the nanoflash technique applied to thermal conductivity evaluation. A. O. Maselugbo, B. L. Sadiku and J. R. Alston, The results of proposed models were compared to 23 well-known theoretical and empirical models. The fluid is colorless (water white). WebMaintains low electrical conductivity Uses proprietary non-ionic corrosion inhibitor formulation with years of research Can be used with Formulation: Propylene Glycol, p^h72n* 8pW&.=rfeK&=d_">!f4-6%)|Z>,^R :qz*jn88H1 Z'2P?[-ik,2T0!L The present work shows an innovative frame saw machine to cut granite, the eccentric hinge guide mechanism is introduced into the machine. 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. k5fX.TX#HksQ} >6!"vg8{!SP/(b8#_"hr 1q"I}\gxu'Gxq`j^vGF`i R7`md\qM._8>)pbE.x%6s&Eg)c^mDO1 }rZ~&\!=[aHM3]qIvT=nD{vf!oSAc0T]z4J0({(YxkyCWboRycfP'{ug04tTS[eun-8'$Q)^U/+jkaIB@^%BX# WebLearn about the chemical and physical properties of Ethylene Glycol/water mixtures, on our blog. The thermal performance of the internal heat transfer fluid was an important factor affecting the heat transfer efficiency of the exchanger system. Read more about how to correctly acknowledge RSC content. The propylene glycol/water mixtures at different weight ratios were used as base fluids for the preparation of stable ND nanofluids. Chemical treatment was used to make ND nanoparticles with an average size of 5.42nm. 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. 0000002101 00000 n 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. WebBNNBs exhibit high thermal conductivity due to efficient phonon transfer and they are electrical insulators owing to their wide bandgap. [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. Under constant heat flux conditions, ZnOPG nanofluids exhibited linear increase in heat removal rates with increasing nanoparticle concentration. [34] for Al2O3/PG and TiO2/PG nanofluids. 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. 0000002868 00000 n Because dissolved salts and other inorganic chemicals conduct electrical current, conductivity increases as salinity increases. The purification of UDD powders is important for achieving good stable nanofluids. 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 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]. 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. 0000017674 00000 n 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. 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. Branson et al. Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, USA [20] obtained thermal conductivity enhancement of 17.23% for ND/EG nanofluid at 1.0vol.% at a temperature of 30C. 0 trailer PGI is a colorless, water soluble, hygroscopic liquid with a characteristic glycol odor, medium viscosity, low vapor E-mail: Additionally, surface tension and electrical conductivity are investigated. 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. The thermal conductivity of 0.1vol% of N-CQDs nanofluid increased by 43.21% at 50C compared to the base fluid. 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. 2 shows the IR spectra of UDD powders, acid treated, salt and sucrose milled samples. Chemical co-precipitation was used for the synthesis of large quantity of Fe3O4 nanoparticles with an average particle size of 11.42nm. 0000003320 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. 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 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%. 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. [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.%. [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. 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. %%EOF Fig. 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. 0000133274 00000 n 0000088822 00000 n 0000088462 00000 n 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. please go to the Copyright Clearance Center request page. 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. Accurate estimation of thermal conductivity (TC) of nanofluids is essential in thermophysical studies of nanofluids. The article presents the results of detailed studies of the thermal conductivity of the water slurry of microencapsulated PCM (mPCM) and slurry based on waterpropylene glycol solutions. 0000089466 00000 n The viscosity of N-CQDs nanofluid behaves as a Newtonian fluid. 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 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 Prasher et al. of nanofluid, the exergy efficiency is 22.97%, while for ethylene glycol, it is 6.78%. Another method for removing the carbon impurities from the UDD powders is with dry salt or dry sucrose [10]. 0000033853 00000 n Appl. This study reports a nanofluid that achieves long-term stability without any additives. 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. 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. 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. The Raman, TEM and XRD analysis was also performed on acid treated nanodiamond particles. Nanoscale, 2023, Advance Article Measuring glycol concentrations by electrical conductivity is not recommended, especially in process systems, heat exchangers, etc. The quality of The inadequacy of the widely used VogelTammannFulcher or WilliamsLandelFerry equations to describe the temperature variation of the vacuum

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