The results of proposed models were compared to 23 well-known theoretical and empirical models. 209 0 obj<>stream 11 is presented the percentage thermal conductivity enhancement [(knfkbf)/kbf100] for these ratios along with the data with the data of Palabiyik et al. 0000000016 00000 n Corresponding authors, a 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. 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. of propylene glycol 0000047379 00000 n 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 statistical and graphical results showed that the proposed models are more precise and reliable than the existing ones in literature. 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. The exergy analysis and heat transfer characteristics pertaining to the heat exchanger were also investigated. In this particular system we are using an expansion tank with a bladder, so we don't have a make-up pump. The rheological behaviour is investigated through rotational rheometry. 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. Thus, the new prototype machine is suitable for sawing granite. Prasher et al. Yu et al. 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. 2 shows the IR spectra of UDD powders, acid treated, salt and sucrose milled samples. However, those results have not been collectively compared or discussed. The electrical conductivity of glycol mixtures within the range of 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] analysis.knfkbf=1+Cknfbf=1+Cwhere, is the volume concentration, Ck and C are the thermal conductivity and viscosity enhancement coefficients. endstream endobj 181 0 obj<. 40-48, Applied Thermal Engineering, Volume 90, 2015, pp. conductivity of propylene glycol 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%. It was observed that the position of the thermocouples can result in an under-estimation of the Nusselt number. 2016 Elsevier B.V. All rights reserved. 499-508, Energy Conversion and Management, Volume 96, 2015, pp. Electrical 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 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). 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. WebMaintains low electrical conductivity Uses proprietary non-ionic corrosion inhibitor formulation with years of research Can be used with Formulation: Propylene Glycol, Engineering and Operating Guide for Dowfrost and Dowfrost HD 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. in a third-party publication (excluding your thesis/dissertation for which permission is not required) WebDOWFROSTfluid is a formulation of 95.5 percent propylene glycol, dipotassium phosphate and water. Conductivity is also affected by temperature: the warmer the water, the higher the conductivity. The present findings are consistent with those of Palabiyik et al. Therefore, there is no literature on the thermal properties of PG/W mixture based ND nanofluids. [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 formation of carboxyl (COOH) groups on the surface of nanodiamond was analyzed by FTIR. Please enable JavaScript 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. 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 sensitivity analysis illustrated that temperature has the highest effect on the relative TC followed by base fluid TC and particle volume fraction. Sundar et al. p^h72n* 8pW&.=rfeK&=d_">!f4-6%)|Z>,^R :qz*jn88H1 Z'2P?[-ik,2T0!L 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. 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. Thermal conductivity of nanoparticle-fluid mixture. This paper investigates the significance of some micro scaling effects in micro-channel absorber plates. 0000125049 00000 n Namburu et al. 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 WebLearn about the chemical and physical properties of Ethylene Glycol/water mixtures, on our blog. 0000088462 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. 0 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. Measuring glycol concentrations by electrical conductivity is not recommended, especially in process systems, heat exchangers, etc. The quality of 0000073108 00000 n 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. 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. 0000115846 00000 n 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. [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.%. New thermal conductivity and viscosity correlations have been developed based on the experimental data. You do not have JavaScript enabled. 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. 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 Propylene glycol 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. 1000W/mK and Young's modulus, high electrical resistivity, attractive optical characteristics, and excellent chemical stability and biocompatibility. PGI is a colorless, water soluble, hygroscopic liquid with a characteristic glycol odor, medium viscosity, low vapor 0000133274 00000 n The main advantages of this measurement technique are short measurement times, easy sample preparation and high accuracy. Chemical treatment was used to make ND nanoparticles with an average size of 5.42nm. They also observed the formation of carboxyl groups on the surface of ND particles based on the FTIR analysis. Table 8-3-1 - Properties of mixture Water/Glycol - CERN This study investigates theoretically and experimentally the electrical and thermal conductivities of 50/50 water-ethylene glycol based TiO 2 nanofluids with Based on the above methods the acid treatment method is more effective compared to other salt and sucrose methods. provided correct acknowledgement is given. 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. Reynolds numbers were in the range 10100 and fluid inlet temperatures ranged from 5 to 40C. FROZKHQ KHDWHGLQWKH+9HOHFWULFILHOG Prasher et al. 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. 245-255, Applied Thermal Engineering, Volume 91, 2015, pp. Electrical and Thermal Conductivities of 50/50 Water In the heat exchanger, the hot fluid passes through the shell side and the cold fluid (nanofluid) passes through the helical coil side. 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. An enhancement of 4.24% in heat transfer rate was observed with 2vol.% ZnOPG nanofluid. DOW Propylene Glycol, Industrial Grade Due to its exceptional thermal, mechanical and electrical properties, diamond has attracted attention for use as a nanoparticle in fluids. [25], [26] also prepared 20:80%, 40:60% and 60:40% EG/W based Fe3O4 nanofluids and measured both thermal conductivity and viscosity experimentally. [27] prepared PG based Al2O3 nanofluids and estimated viscosity experimentally and proposed viscosity model. 0000017674 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. Additionally, surface tension and electrical conductivity are investigated. 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. Branson et al. Liquids - Thermal Conductivities - Engineering ToolBox 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. Conjugate heat transfer was found to reduce the Nusselt number which agrees with the literature, this also resulted in a Peclet number dependent Nusselt number. The preparation of ND based nanofluids and their thermal properties are given below. The X-ray powder diffraction (XRD), transmission, C, respectively compared to their respective base fluids. The viscosity of N-CQDs nanofluid behaves as a Newtonian fluid. 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 ). Our results indicate that the surfactant-free, ZnOPG nanofluids behave like liquid coolants but with improved thermal conductivity and specific heat and hence suitable for energy management. 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. 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 0000060250 00000 n The instrument is based on transient plane source (TPS) technique and is widely used for thermal conductivity measurement. 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 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]. Yeganeh et al. 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. 0000087536 00000 n 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. 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. An enhancement of thermal conductivity with respect to temperature and volumetric concentration is found, as expected. 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 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. Islam, R.; Shabani, B. Read more about how to correctly acknowledge RSC content. 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 If you are the author of this article, you do not need to request permission to reproduce figures Annual production of propylene glycol in The earlier works reveals the preparation, estimation of thermal conductivity and viscosity of PG/W mixture based Al2O3, CuO, and Fe3O4 nanofluids. WebThere are two main types of water glycol mixtures used in heating/cooling systems that mix well in water at any concentration. Nanofluids offer many opportunities to enhance the efficiency of thermal systems by improving the thermal properties of the host fluids. The formation of carboxyl (COOH) groups on the surface of ND particles was analyzed by FTIR spectrum. 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 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. Substance and % by volume in mixture: Minimal working temperature [o C] of nanofluid, the exergy efficiency is 22.97%, while for ethylene glycol, it is 6.78%. [14,15] for mono nanofluids based on the same base fluid, propylene glycol:water 20:80 wt%. 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 When compared to Propylene glycolwater (50:50) along with Propylene glycolwater (50:50) dispersed with 0.25% Graphene, it is clear from Fig. The thermal conductivity and viscosity of ND nanofluids were estimated experimentally at different particle concentrations and temperatures. 0000086902 00000 n The acid treated ND particles were characterized by XRD, TEM, FTIR and XPS.