Abstract
The paper presents the results of measurements of the thermal conductivity of \(\hbox{MgAl}_2\hbox{O}_4\)-DG nanofluids. The dependence of the thermal conductivity on concentration of nanoparticles in various temperatures from 293.15 to 338.15 K with 15 K step was examined. Experimental data was modeled with existing theoretical models describing the effects of the concentration of particles on the thermal conductivity of the suspension. It was presented that thermal conductivity of \(\hbox{MgAl}_2\hbox{O}_4\)-DG nanofluids increases proportional to volume concentration of nanoparticles.
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1 Introduction
Nanofluids are suspensions of particles of nanometrical sizes in base liquid. Due to the huge potential for the use of these engineering materials [1,2,3], particularly in the field of heat exchange [4,5,6,7] studies on the basic physical properties are conducted by many scientific groups worldwide. Experiments are carried out mainly on rheological and thermal properties, with particular emphasis on thermal conductivity.
Many studies have shown that thermal conductivity of the liquid increases when the nanoparticles are dispersed therein [8,9,10,11,12,13,14,15,16,17]. This increase might be particularly interesting both for engineers planning to practical applications of nanofluids as well as for researchers trying to understand the mechanisms responsible for this phenomenon. More specifically, dependence of the thermal conductivity on concentration was examined by Albadr et al. [18] and Xuan et al. [19].
The thermal properties of nanofluids affects not only the nature of the particles in suspension. Anoop et al. [20], and Teng et al. [21] presented, that thermal conductivity increases with decreasing particle size for \(\hbox{Al}_2\hbox{O}_3\) nanofluids, the same relation was presented by Esfe et al. [22] for Fe–water nanofluids. A similar dependence—a decrease in thermal conductivity with increasing size of the nanoparticles—was presented by Wang et al. [23] for \(\hbox{Fe}_2\hbox{O}_3\) particles and Zhou et al. [24].
Another factor which may affect the thermal properties of nanofluids is the shape of the particles in suspension. Jeong et al. [25] conducted a research on ZnO nanofluids which resulted in the show that thermal conductivity of rectangular shape particle suspensions were higher than spheres. Dependence of thermal conductivity on the shape of the nanoparticles in nanofluids was also study by Timofeeva et al. [26].
Thermal conductivity of nanofluids mostly increase with the temperature [10, 27, 28]. But not all nanofluids present that kind of behavior. Mariano et al. [29] have shown that for ethylene glycol-based \(\hbox{Co}_3\hbox{O}_4\) nanofluids thermal conductivity decreases with temperature. Very interesting results of dependence of thermal conductivity on temperature was presented by Li et al. [30] for diathermic oil based SiC nanofluids. They presented that for low volume concentration thermal conductivity decrease with temperature, and for high volume concentration it increase.
In view of the fact that the addition of nanoparticles to liquid relies only on the thermal conductivity increase, it is clear that the type of base liquid used to produce the nanofluids is one of the most important factor for the values of thermal conductivity of nanofluids.
Also of interest are the rheological properties of nanofluids. It has been shown that depending on the type of nanoparticles, nanofluids may present Newtonian [17, 27, 29] or non-Newtonian [31,32,33,34,35] nature. In addition, some of nanofluids have interesting electrorheological [36, 37] and magnetorheological [38] properties.
The \(\hbox{MgAl}_2\hbox{O}_4\)-DG nanofluids present complex rheological properties [39], this materials have non-Newtonian shear-thinning nature. It has been also observed the interesting phenomenon, formation of agglomerates of nanoparticles during rotational viscosity measurements, which resulted in changes in viscosity of nanofluids [40].
2 Materials and methods
2.1 Nanoparticles characterization
The \(\hbox{MgAl}_2\hbox{O}_4\) nanopowder which was used in this examinations is commercially available magnesium-aluminum spinel manufactured by Baikowski (Annecy, France), ID LOT: 101488. The average size of the crystallites measured with X-Ray Diffraction was 40 nm, and it was confirmed on scanning electron microscope pictures, which might be found in Ref. [39].
The size distribution of particles is based on measurements of the hydrodynamic diameter in suspension with use of Zetasizer Nano ZS (Malvern Instruments Ltd, Worcestershire, UK). Measurements was conducted on diluted suspensions of particles in diethylene glycol (0.2 g/l), which underwent ultrasonication (VibraCell VCX130, Sonics & Materials, Inc., Newtown, USA) prior measurements. Result of this measurement was presented in Fig. 1. The average hydrodynamic diameter of particles determined on the basis of this method is 215 nm.
To determine the thermal conductivity of \(\hbox{MgAl}_2\hbox{O}_4\) nanopowder, its’ thermal diffusivity was measured. Thermal diffusivity of the sample was measured at room temperature by the laser flash method utilizing a Laser Flash Apparatus (LFA 427 Netzsch Geraotebau GmbH, Selb, Germany). Then, based on the method presented by Parker et al. [41] thermal conductivity of the material was calculate. Thermal conductivity of \(\hbox{MgAl}_2\hbox{O}_4\) nanopowder determined in this measurement is 14.406 W/(m K) at room temperature.
Density of \(\hbox{MgAl}_2\hbox{O}_4\) nanopowder was measured with use of a helium pycnometer Ultrapyc 1200e (Quantachrome Instruments, Boynton Beach, USA). Temperature inside measuring chamber was stabilized at 297.15 K by thermostat Grant TC120 (Grant Instruments, Cambridgeshire, GB). The density value was calculate as a average from two series of measurements where each included five unit measurements. Before density measurements nanopowder was dried in temperature of 403.15 K for 2 h. The density of \(\hbox{MgAl}_2\hbox{O}_4\) nanopowder is 3.3626 g/(cm3) at room temperature.
2.2 Sample preparation
Samples were prepared in the various mass concentration (5, 15, 25 wt%) by using an analytical balance WAS 220/X (Radwag, Radom, Poland) with the accuracy of 0.1 mg. In order to break up the agglomerates of nanoparticles mechanical stirring in a mechanical shaker Genius 3 Vortex (IKA, Staufen, Germany) for 30 min, and the ultrasound for a period of 200 min in ultrasoundwave bath Emmi 60 HC (EMAG, Moerfelden-Walldorf, Germany). All samples were prepared at room temperature not exceeding 298.15 K. Volume concentrations of nanofluids were calculated from equation:
where \(\varphi _v\) and \(\varphi _m\) are volume and mass concentration, \(\rho _p\) and \(\rho _0\) stands for density of solid particles and base fluid.
2.3 Thermal conductivity measurements
To investigate the thermal conductivity of the nanofluids, a KD2 Pro Thermal Properties Analyzer (Decagon Devices Inc., Pullman, Washington, USA) device was used. This equipment is popular, and was previously used by many research groups to study the thermal properties of nanofluids, for example in Ref. [11, 27, 42,43,44,45]. The sample was thermostated with the probe in for 30 min in a water bath MLL 547 (AJL Electronic, Cracow, Poland) before measurement. The volume of the examined sample was 30 ml. Time between successive measurements of the thermal conductivity of the sample was 15 min. Uncertainty of measurement did not exceed 2%, and a detailed description of the calibration process has been presented in Ref. [46]. The thermal conductivity of nanofluids were tested immediately after preparation of the sample.
3 Results and discussion
Thermal conductivity of \(\hbox{MgAl}_2\hbox{O}_4\)-DG nanofluids were measured in temperature range from 293.15 to 338.15 K with 15 K step for various volume concentrations between 1.7 and 10%. The results of these measurements are summarized in Table 1. It might be noticed that the thermal conductivity increases with volume concentration of nanoparticles at each measured temperature, as presented in Fig. 2.
In the 19th century, Maxwell [47] presented a theoretical model describing the thermal conductivity of suspensions of spherical particles in the form of:
where \(k_{nf}\), \(k_p\), and \(k_0\) are thermal conductivity of the nanofluid, solid particles, and base fluid respectively. Jeffrey [48] introduced model which considering a suspension of spherical particles:
where \(\beta =\frac{\gamma -1}{\gamma +2}\), and \(\gamma =\frac{k_p}{k_0}\).
Turian et al. [49], based on thermal conductivity data on many base fluids presented another model:
Turian et al. assumed that the Maxwell model is right for suspensions, in which \(k_p/k_0 \approx 1\), while the model proposed by them had to be right for the suspensions, in which \(k_p/k_0 > 4\).
Experimental data for thermal conductivity of \(\hbox{MgAl}_2\hbox{O}_4\)-DG nanofluids shows that the \(k_{nf}/k_0\) ratio enhancement is linear with volume concentration of nanoparticles. Using gnuplot software fit a linear function to the received data, was conducted. The function takes form:
while asymptotic standard error of parameter was ±0.01099 (0.3122%).
Figure 3 presents the experimental results, theoretical models fits, and a linear function (5) fit for measurements conducted at 293.15 K.
4 Conclusions
The paper presents results of investigation of the dependence of \(\hbox{MgAl}_2\hbox{O}_4\)-DG nanofluids thermal conductivity on the volume concentration of nanoparticles at various temperatures. It was presented that the thermal conductivity increase linearly with volume concentration of nanoparticles in nanofluids. It was also found that \(\hbox{MgAl}_2\hbox{O}_4\)-DG nanofluids presents, repeatedly reported for other types of nanofluids, increase in thermal conductivity with temperature.
References
Saidur R, Leong K, Mohammad H (2011) A review on applications and challenges of nanofluids. Renew Sustain Energy Rev 15(3):1646–1668
Taylor R, Coulombe S, Otanicar T, Phelan P, Gunawan A, Lv W, Rosengarten G, Prasher R, Tyagi H (2013) Small particles, big impacts: a review of the diverse applications of nanofluids. J Appl Phys 113(1):011,301
Abu-Nada E (2008) Application of nanofluids for heat transfer enhancement of separated flows encountered in a backward facing step. Int J Heat Fluid Flow 29(1):242–249
Kulkarni DP, Das DK, Vajjha RS (2009) Application of nanofluids in heating buildings and reducing pollution. Appl Energy 86(12):2566–2573
Huminic G, Huminic A (2012) Application of nanofluids in heat exchangers: a review. Renew Sustain Energy Rev 16(8):5625–5638
Said Z, Sajid M, Alim M, Saidur R, Rahim N (2013) Experimental investigation of the thermophysical properties of Al2O3-nanofluid and its effect on a flat plate solar collector. Int Commun Heat Mass Transf 48(0):99–107
Saidur R, Meng T, Said Z, Hasanuzzaman M, Kamyar A (2012) Evaluation of the effect of nanofluid-based absorbers on direct solar collector. Int J Heat Mass Transf 55(21–22):5899–5907
Pang C, Lee JW, Kang YT (2015) Review on combined heat and mass transfer characteristics in nanofluids. Int J Therm Sci 87(0):49–67
Yu W, Xie H, Li Y, Chen L (2011) Experimental investigation on thermal conductivity and viscosity of aluminum nitride nanofluid. Particuology 9(2):187–191
Pastoriza-Gallego MJ, Lugo L, Legido JL, Piñeiro MM (2011) Enhancement of thermal conductivity and volumetric behavior of fexoy nanofluids. J Appl Phys 110(1):014309
Pastoriza-Gallego M, Lugo L, Legido J, Piñeiro M (2011) Thermal conductivity and viscosity measurements of ethylene glycol-based Al2O3 nanofluids. Nanoscale Res Lett 6(1):221
Wei X, Kong T, Zhu H, Wang L (2010) CuS/Cu2S nanofluids: synthesis and thermal conductivity. Int J Heat Mass Transf 53(9 10):1841–1843
Xie H, Yu W, Chen W (2010) MgO nanofluids: higher thermal conductivity and lower viscosity among ethylene glycol-based nanofluids containing oxide nanoparticles. J Exp Nanosci 5(5):463–472
Yu W, Xie H, Chen L, Li Y (2009) Investigation of thermal conductivity and viscosity of ethylene glycol based ZnO nanofluid. Thermochim Acta 491(1 2):92–96
Hu P, Shan WL, Yu F, Chen ZS (2008) Thermal conductivity of AlN–ethanol nanofluids. Int J Thermophys 29(6):1968–1973
He Y, Jin Y, Chen H, Ding Y, Cang D, Lu H (2007) Heat transfer and flow behaviour of aqueous suspensions of TiO2 nanoparticles (nanofluids) flowing upward through a vertical pipe. Int J Heat Mass Transf 50(11–12):2272–2281
Esfe MH, Saedodin S, Asadi A, Karimipour A (2015) Thermal conductivity and viscosity of Mg(OH)2-ethylene glycol nanofluids. J Therm Anal Calorim. doi:10.1007/s10973-015-4417-3
Albadr J, Tayal S, Alasadi M (2013) Heat transfer through heat exchanger using Al2O3 nanofluid at different concentrations. Case Stud Therm Eng 1(1):38–44
Xuan Y, Li Q (2000) Heat transfer enhancement of nanofluids. Int J Heat Fluid Flow 21(1):58–64
Anoop K, Sundararajan T, Das SK (2009) Effect of particle size on the convective heat transfer in nanofluid in the developing region. Int J Heat Mass Transf 52(9–10):2189–2195
Teng TP, Hung YH, Teng TC, Mo HE, Hsu HG (2010) The effect of alumina water nanofluid particle size on thermal conductivity. Appl Therm Eng 30(14 15):2213–2218
Hemmat Esfe M, Saedodin S, Wongwises S, Toghraie D (2015) An experimental study on the effect of diameter on thermal conductivity and dynamic viscosity of Fe/water nanofluids. J Therm Anal Calorim 119(3):1817–1824
Wang B, Wang B, Wei P, Wang X, Lou W (2012) Controlled synthesis and sizedependent thermal conductivity of \(\text{Fe}_3\text{O}_4\) magnetic nanofluids. Dalton Trans 41:896–899
Zhou XF, Gao L (2008) Thermal conductivity of nanofluids: effects of graded nanolayers and mutual interaction. J Appl Phys 103(8):083503
Jeong J, Li C, Kwon Y, Lee J, Kim SH, Yun R (2013) Particle shape effect on the viscosity and thermal conductivity of ZnO nanofluids. Int J Refrig 36(8):2233–2241
Timofeeva EV, Routbort JL, Singh D (2009) Particle shape effects on thermophysical properties of alumina nanofluids. J Appl Phys 106(1):014304
Pastoriza-Gallego M, Lugo L, Cabaleiro D, Legido J, Pineiro M (2014) Thermophysical profile of ethylene glycol-based ZnO nanofluids. J Chem Thermodyn 73(0):23–30
Kleinstreuer C, Feng Y (2011) Experimental and theoretical studies of nanofluid thermal conductivity enhancement: a review. Nanoscale Res Lett 6(1):229
Mariano A, Pastoriza-Gallego MJ, Lugo L, Mussari L, Pineiro MM (2015) Co3O4 ethylene glycol-based nanofluids: thermal conductivity, viscosity and high pressure density. Int J Heat Mass Transf 85(0):54–60
Li X, Zou C, Zhou L, Qi A (2016) Experimental study on the thermo-physical properties of diathermic oil based SiC nanofluids for high temperature applications. Int J Heat Mass Transf 97:631–637
Li X, Zou C, Wang T, Lei X (2015) Rheological behavior of ethylene glycol-based SiC nanofluids. Int J Heat Mass Transf 84(0):925–930
Mariano A, Pastoriza-Gallego MJ, Lugo L, Camacho A, Canzonieri S, Pineiro MM (2013) Thermal conductivity, rheological behaviour and density of non-newtonian ethylene glycol-based SnO2 nanofluids. Fluid Phase Equilib 337(0):119–124
Duan F, Wong T, Crivoi A (2012) Dynamic viscosity measurement in non-Newtonian graphite nanofluids. Nanoscale Res Lett 7(1):360
Pastoriza-Gallego M, Lugo L, Legido J, Piñeiro M (2011) Rheological non-newtonian behaviour of ethylene glycol-based Fe2O3 nanofluids. Nanoscale Res Lett 6(1):560
Żyła G, Fal J, Gizowska M, Witek A, Cholewa M (2015) Dynamic viscosity of aluminum oxide-ethylene glycol (Al2O3-EG) nanofluids. Acta Phys Pol A 128(2):240
Raykar VS, Sahoo S, Singh AK (2010) Giant electrorheological effect in Fe2O3 nanofluids under low dc electric fields. J Appl Phys 108(3):034306–034306-5
Prekas K, Shah T, Soin N, Rangoussi M, Vassiliadis S, Siores E (2013) Sedimentation behaviour in electrorheological fluids based on suspensions of zeolite particles in silicone oil. J Colloid Interface Sci 401(0):58–64
Thirupathi G, Singh R (2014) Magneto-viscosity of MnZn-ferrite ferrofluid. Phys B Condens Matter 448:346–348
Żyła G, Cholewa M, Witek A (2013) Rheological properties of diethylene glycol-based MgAl2O4 nanofluids. RSC Adv 3(18):6429–6434
Żyła G, Cholewa M (2014) On unexpected behavior of viscosity of diethylene glycol-based MgAl2O4 nanofluids. RSC Adv 4:26057–26062
Parker WJ, Jenkins RJ, Butler CP, Abbott GL (1961) Flash method of determining thermal diffusivity, heat capacity, and thermal conductivity. J Appl Phys 32(9):1679–1684
Mondragon R, Segarra C, Jarque JC, Julia JE, Hernondez L, Martinez-Cuenca R (2012) Characterization of physical properties of nanofluids for heat transfer application. J Phys Conf Ser 395(1):012,017
Yang L, Du K, Zhang XS (2012) Influence factors on thermal conductivity of ammoniawater nanofluids. J Cent South Univ 19(6):1622–1628
Mostafizur R, Bhuiyan M, Saidur R, Aziz AA (2014) Thermal conductivity variation for methanol based nanofluids. Int J Heat Mass Transf 76(0):350–356
Li X, Zou C, Lei X, Li W (2015) Stability and enhanced thermal conductivity of ethylene glycol-based SiC nanofluids. Int J Heat Mass Transf 89:613–619
Żyła G (2016) Thermophysical properties of ethylene glycol based yttrium aluminum garnet (Y3Al5O12-EG) nanofluids. Int J Heat Mass Transf 92:751–756
Maxwell JC (1892) A treatise on electricity and magnetism, 3rd edn. Oxford University Press, London
Jeffrey DJ (1973) Conduction through a random suspension of spheres. Proc R Soc Lond A Math Phys Sci 335(1602):355–367
Turian RM, Sung DJ, Hsu FL (1991) Thermal conductivity of granular coals, coal-water mixtures and multi-solid/liquid suspensions. Fuel 70(10):1157–1172
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Żyła, G., Fal, J., Gizowska, M. et al. Thermal conductivity of diethylene glycol based magnesium–aluminum spinel (MgAl2O4-DG) nanofluids. Heat Mass Transfer 53, 1905–1909 (2017). https://doi.org/10.1007/s00231-016-1948-5
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DOI: https://doi.org/10.1007/s00231-016-1948-5