Download : Download high-res image (216KB)Download : Download full-size image. 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. 107-98-2) Propylene Glycol Methyl Ether Acetate (PMA; CAS No. Correlations for the thermo-physical properties of the nanofluid were developed. WebBNNBs exhibit high thermal conductivity due to efficient phonon transfer and they are electrical insulators owing to their wide bandgap. The inadequacy of the widely used VogelTammannFulcher or WilliamsLandelFerry equations to describe the temperature variation of the vacuum 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. The thermal performance of the internal heat transfer fluid was an important factor affecting the heat transfer efficiency of the exchanger system. 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%. Forced convection experiments were performed on an instrumented metal plate with micro-channels. The results are beneficial for the design and operation of micro-channel absorber plates. An enhancement of thermal conductivity with respect to temperature and volumetric concentration is found, as expected. p^h72n* 8pW&.=rfeK&=d_">!f4-6%)|Z>,^R :qz*jn88H1 Z'2P?[-ik,2T0!L An enhancement of 4.24% in heat transfer rate was observed with 2vol.% ZnOPG nanofluid. 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 optimized method for purifying the UDD powders is established. Please enable JavaScript Another method for removing the carbon impurities from the UDD powders is with dry salt or dry sucrose [10]. of nanofluid, the exergy efficiency is 22.97%, while for ethylene glycol, it is 6.78%. 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. 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. This study investigates theoretically and experimentally the electrical and thermal conductivities of 50/50 water-ethylene glycol based TiO 2 nanofluids with 209 0 obj<>stream provided correct acknowledgement is given. This study reports a nanofluid that achieves long-term stability without any additives. Measuring glycol concentrations by electrical conductivity is not recommended, especially in process systems, heat exchangers, etc. The quality of 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. jralston1@ncat.edu, b [20] obtained thermal conductivity enhancement of 17.23% for ND/EG nanofluid at 1.0vol.% at a temperature of 30C. 0000125049 00000 n These plates are to be used in a proposed compact (thin and light-weight) solar thermal flat plate collector (FPC). 2016 Elsevier B.V. All rights reserved. [27] analysis.knfkbf=1+Cknfbf=1+Cwhere, is the volume concentration, Ck and C are the thermal conductivity and viscosity enhancement coefficients. please go to the Copyright Clearance Center request page. 181-190, International Journal of Heat and Mass Transfer, Volume 129, 2019, 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. 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 0000073108 00000 n Reynolds numbers were in the range 10100 and fluid inlet temperatures ranged from 5 to 40C. In addition, both cutting efficiency and slab flatness were recorded. [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. One of the authors (L.S.S.) Annual production of propylene glycol in 0000002234 00000 n 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 Energy . Sundar et al. 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. 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 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%. 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. Forget about conductivity, it is directly related to temperature and is used in domestic/process water systems (water treatment) where you don't ha 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 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 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. 0000142997 00000 n Nanodiamondwater nanofluids were prepared and estimated the thermal conductivity, viscosity and also estimated their potential use in heat transfer applications. Based on the above methods the acid treatment method is more effective compared to other salt and sucrose methods. 0000087536 00000 n 0000003207 00000 n Sundar et al. 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 ). Comparisons with data from literature confirmed the validity and the suitability of the nanoflash technique applied to thermal conductivity evaluation. 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. 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). 180 0 obj <> endobj Yeganeh et al. 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. Corresponding authors, a [27] analysis if the value of C/Ck<4 then the nanofluid is heat transfer beneficial fluid. The carbon impurities present in the UDD powders have been removed using mixture of H2SO4 and HNO3 [5], [6], [7], [8], [9]. 180 30 The preparation of ND based nanofluids and their thermal properties are given below. 0 xref However, experimental studies that jointly explore the physical properties of hybrids and the corresponding mono nanofluids are missing. 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 WebLearn about the chemical and physical properties of Ethylene Glycol/water mixtures, on our blog. 0000002832 00000 n * 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. Joint School of Nanoscience and Nanoengineering, North Carolina A&T State University, Greensboro, NC 27401, USA The starting product, MICRONAL 5428 X, which contains about 43% microencapsulated paraffin with a transformation temperature of 28 If you are an author contributing to an RSC publication, you do not need to request permission WebPropylene glycol is a colourless liquid that is relatively viscous, has no odour, and tastes slightly sweet. The PG/W nanofluids are prepared with acid treated ND particles. However, conjugate heat transfer and measurement uncertainties were significant. Jee and Lee [11] used strong acids of H2SO4 and HNO3 in the molar ratio of 3:1 for the purification of UDD powders and observed the removal of carbon impurities. The formation of carboxyl (COOH) groups on the surface of nanodiamond was analyzed by FTIR. Nanofluids offer many opportunities to enhance the efficiency of thermal systems by improving the thermal properties of the host fluids. 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. 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. A binary mixture of propylene glycol and water at 20:80 mass ratio offers protection against freezing up to 265.98 K [13], making it suitable as a heat transfer fluid How about a secondary heat exchanger, i.e primary steam/water heats intermediate water. Intemediate water is pumped to a secondary heat exchanger w 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 earlier works reveals the preparation, estimation of thermal conductivity and viscosity of PG/W mixture based Al2O3, CuO, and Fe3O4 nanofluids. 8 . Among all the carbon materials ND particles creates great interest because of their superior hardness, thermal conductivity, i.e. Chemical treatment was used to make ND nanoparticles with an average size of 5.42nm. The reason for the agglomeration of UDD powders in the base fluid is due to the presence of carbon impurities. PGI is a colorless, water soluble, hygroscopic liquid with a characteristic glycol odor, medium viscosity, low vapor The frictional exergy destruction is found to contribute together with heat transfer exergy destruction to the total entropy of the SCHE system. 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]. 5. 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. %%EOF , DOI: 10.1039/D2NR06332H. 0000047379 00000 n 0000133274 00000 n Hybrid nanofluids aim to further improve the characteristics of mono nanofluids. Prasher et al. [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.%. 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 thermal conductivity of single phase heat transfer fluids may be enhanced by dispersing small quantity of solid particles. 0000089466 00000 n 1000W/mK and Young's modulus, high electrical resistivity, attractive optical characteristics, and excellent chemical stability and biocompatibility. It was observed that the position of the thermocouples can result in an under-estimation of the Nusselt number. 0000088822 00000 n Results showed that ND nanofluids achieved higher heat transfer coefficients than the base fluid. endstream endobj 181 0 obj<. The viscosity of N-CQDs nanofluid behaves as a Newtonian fluid. 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. 40-48, Applied Thermal Engineering, Volume 90, 2015, pp. 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. 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.%. model and the Mouromtseff number were used to study the heat transfer capability of ND nanofluid under laminar and turbulent flow conditions. 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. For 1.0% vol. 0000002101 00000 n Tyler et al. Nanodiamond (ND) nanoparticles of primary particle size of 510nm can be produced in large quantity by using commercially available ultra-dispersed diamond (UDD) powders. The functional groups on the treated UDD powders were analyzed by FTIR. The fluid is colorless (water white). 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. 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. The proportion of micro-fractured and good diamonds in the new frame saw machine are 45% and 25%, respectively, and the productivity of the new machine is between 6 and 15m2/h. Xu X, Choi SUS. . When compared to Propylene glycolwater (50:50) along with Propylene glycolwater (50:50) dispersed with 0.25% Graphene, it is clear from Fig. 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. trailer 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. The findings suggest that BNNBs have great potential for use as thermally conductive nanoparticles in nanofluids for various heat transfer applications. The heat transfer applications of prepared ND nanofluids in a fully developed laminar flow (Reynolds number, Re<2300) can be evaluated based on the Prasher et al. Thereby, nanofluids have proven to be useful in applications, especially electronic cooling, where increasing thermal properties and avoiding electrical conductivity are vital. This paper investigates the significance of some micro scaling effects in micro-channel absorber plates. 2 shows the IR spectra of UDD powders, acid treated, salt and sucrose milled samples. Diamond circular saws and diamond wire saws present some technological limits, and the marble frame saw cannot process granite by now. 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. [25], [26] also prepared 20:80%, 40:60% and 60:40% EG/W based Fe3O4 nanofluids and measured both thermal conductivity and viscosity experimentally. 115-123, International Communications in Heat and Mass Transfer, Volume 76, 2016, pp. Webconductivity. 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 hybrid nanofluid presents intermediate values between those of the mono nanofluids for all the properties except dynamic viscosity. DOWFROSTfluid has an operating Islam, R.; Shabani, B. 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. Appl. The preparation and properties of hybrid nanofluids containing diamond nanoparticles are analyzed and discussed in detail, and a list of potential uses for these enhanced heat transfer fluids in industrial and commercial applications is provided and deliberated. 499-508, Energy Conversion and Management, Volume 96, 2015, pp. would like to thank FCT for his post-doctoral research grant: SFRH/BPD/79104/2011. 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%. MEG (Mono Ethylene Glycol) or C2H6O2. In the heat exchanger, the hot fluid passes through the shell side and the cold fluid (nanofluid) passes through the helical coil side. 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. [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. 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. Substance and % by volume in mixture: Minimal working temperature [o C] You do not have JavaScript enabled. Increasing the concentration of the nanofluid beyond 1.0vol% shows a little improvement in the effectiveness of the heat exchanger. The purchased UDD powders treated with strong acid treatment, dry salt and dry sucrose to make them into single ND-crystals. 0000002868 00000 n [23] first time prepared 60:40% (weight ratio) of EG/W based CuO nanofluids and observed viscosity enhancement of 4.5-times and 3.1-times at 6.12vol.% at temperatures of 35C to 50C. 0000060250 00000 n The results of proposed models were compared to 23 well-known theoretical and empirical models. 0000113197 00000 n Because dissolved salts and other inorganic chemicals conduct electrical current, conductivity increases as salinity increases. Conductivity is also affected by temperature: the warmer the water, the higher the conductivity. The statistical and graphical results showed that the proposed models are more precise and reliable than the existing ones in literature. [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. 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. BNNBs exhibit high thermal conductivity due to efficient phonon transfer and they are electrical insulators owing to their wide bandgap. [27] prepared PG based Al2O3 nanofluids and estimated viscosity experimentally and proposed viscosity model. The stability, thermophysical properties and rheological characteristics of N-CQDs nanofluids were investigated. New thermal conductivity and viscosity correlations have been developed based on the experimental data. In this study, the thermal conductivity of graphene/propylene glycol nanofluids is tested using the Hot Disk TPS-500S thermal constants analyzer (Hot Disk AB, Gteborg, Sweden). The main advantages of this measurement technique are short measurement times, easy sample preparation and high accuracy. The purification of UDD powders is important for achieving good stable nanofluids. 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. The sensitivity analysis illustrated that temperature has the highest effect on the relative TC followed by base fluid TC and particle volume fraction. WebThere are two main types of water glycol mixtures used in heating/cooling systems that mix well in water at any concentration. It is hygroscopic, meaning that it readily absorbs water from the surrounding environment. Check with Union Carbide or Dow as they manufacture glycols. I understand they do have a web site. The Raman, XRD and TEM analysis are also used on UDD and ND-acid treated nanoparticles. <50C [21]. 0000088462 00000 n 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 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 different weight ratios of propylene glycol/water mixtures are used as base. 0000086902 00000 n 11 is presented the percentage thermal conductivity enhancement [(knfkbf)/kbf100] for these ratios along with the data with the data of Palabiyik et al. In this particular system we are using an expansion tank with a bladder, so we don't have a make-up pump. 0000086285 00000 n Prasher et al. 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. E-mail: The thermal conductivity results here reported can be compared with those previously published by Sundar et al. The Choi [1] and his team developed nanofluids (fluids contain nanometer size particles) and obtained higher thermal conductivity compared to base fluids. 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. 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. 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# [30] also prepared 20:80%, 40:60% PG/W based Fe3O4 nanofluids and estimated thermal conductivity and viscosity experimentally. [34], in which the nanofluids prepared in pure PG have lower thermal conductivity enhancement than that of. The propylene glycol/water mixtures at different weight ratios were used as base fluids for the preparation of stable ND nanofluids. 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. Thermal conductivity of nanoparticle-fluid mixture. A sawing test and a simulation were carried out to analyze the sawing trajectory, the surface topography of the segments and the percentage of worn diamond particles. 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. 245-255, Applied Thermal Engineering, Volume 91, 2015, pp. 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. The acid treated ND particles were characterized by XRD, TEM, FTIR and XPS. Interactions between spherical and sheet-like nanoparticles explain this behaviour. 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).
Terry Gordy Wife,
Alien Fresh Jerky Owner,
Utah Missing Persons Database,
Articles E
