International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 13, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com Synthesis and characterization of CuO nanoparticles and their use in water based nanofluid for heat transfer applications A. Gupta Research Scholar, Department of Physics, Govt. Auto. Holkar Science College, Bhanwar Kua Square, Indore-452002, Madhya Pradesh, India V.V.S. Murty Professor, Department of Physics, Govt. Auto. Holkar Science College, Bhanwar Kua Square, Indore-452002, Madhya Pradesh, India P. Soni Research Scholar, Department of Physics, Govt. Auto. Holkar Science College, Bhanwar Kua Square, Indore-452002, Madhya Pradesh, India K. Purohit Assistant Professor, Department of Physics, Shri Vaishnav Institute of Management, Gumasta Nagar, Indore-452009, Madhya Pradesh, India . Abstract potential applications mostly for heat transport [4-6] In the present study, Copper Oxide (CuO) in various solar collector systems. In all the nanoparticles were synthesized through co- applications enhancement of heat transfer behavior of precipitation method and dispersed in deionized fluid necessitate for advancing the performance water (DI water) to prepare nanofluid using ultra- efficiency. To meet industrial demand, researchers sonication. Copper nitrate was used as a precursor engineered a new class of materials called nanofluids and sodium hydroxide pellets were used as hydrolysis [7], by consistently dispersing nanoparticles of agent. The size, structure, purity and morphology of metals/nonmetals in base fluid usually water or oil. CuO nano particles were investigated. The EDAX Nanoparticles enhance thermal properties of base analysis revealed the formation of pure CuO fluid such as thermal diffusivity, natural convection nanoparticles without any impurity phase and [8], thermal conductivity, overall heat capacity and determined the ratio of Copper and Oxygen in CuO heat transfer coefficient. Due to large surface area, nanoparticles. The XRD analysis revealed that CuO the nanoparticles drastically influence the thermal nanoparticles are having crystalline structure with properties of base fluid and due to their nano size size ranging from 7 to 16 nm. TEM analysis shows they can be used in micro channels also without any mixed spherical-rod shaped CuO nanoparticle having clog [9]. size ranging from 10 to 17 nm with a little Metal/Metal oxide nanoparticles have very agglomeration. Experimental investigations show that high thermal conductivity as compare to base fluid CuO/DI water nanofluid can transport heat better and hence can be used to increase heat transfer than DI water alone and can be used in heat transfer efficiency of base fluid by increasing its thermal applications. conductivity [10-11]. Many researchers employed carbon nano tubes (CNT) in nanofluid and achieved Keywords: nanoparticles, nanofluid, heat transfer, remarkable increase in thermal conductivity. But the co-precipitation, vertical cylindrical column. demerit of using CNT is possible corrosion-erosion in the system along with high cost of CNT nanofluid Introduction [12]. Yu et al. [13] used ZnO/ EG nanofluid, Heat transfer through fluids has enormous Murshed et al. [14] used TiO2/ water nanofluid, Heris applications [1, 2, 3] in many industrial fields like et al. [15] used Al2O3/water nanofluid and obtained heating, cooling, heat transportation, microelectronics enhancement of thermal properties. Santhilraja and manufacturing. Heat transfer fluids have great et al. [16] were experimentally investigated thermal Page 100 of 104 International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 13, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com conductivity of Al2O3/water, CuO/water and Al2O3- For the preparation of CuO/DI water nano fluid, CuO/water hybrid nanofluids and concluded that 0.07% by volume of obtained CuO nanoparticles hybrid fluid showed synergic effect with maximum were dispersed in 400 ml distilled water by using enhancement in thermal conductivity. Copper oxide magnetic stirrer and after that ultrasonicated for 4 hrs. nanoparticles are prominent to use in nanofluids for thermal engineering applications due to their high Characterizations value of thermal conductivity. Researchers were Structural and phase analysis of CuO nanoparticles studied CuO nanofluid and reported enhancement of were performed by XRD (Bruker Advanced X-ray thermal conductivity and hence heat transfer behavior D8 with Cu kα source) in the 2θ range 20° to 80° and of CuO nanofluid [17, 18, 19, 20]. The enhancement average particle size was calculated for first three in the thermal properties primarily depends upon prominent peaks [(110), (002), (111)]. By using dispersion of nanoparticles in the base fluid, its EDAX, the purity and the composition of the stability, size and shape of nanoparticles [21]. elements of the sample were determined. The Preparation of stable nanofluid, having well- morphology of the CuO nanoparticles was analyzed dispersed nanoparticles for a long time is very using TEM. important and challenging task in the area of The heating experiments were conducted nanofluid research [22]. These problems can be and the temperatures of the DI water and CuO/ DI solved by adopting appropriate synthesis process of water nanofluid are measured simultaneously at nanofluid and nanoparticles. different positions of cylindrical columns with the In the present study nanofluid is prepared by same heat source and the results are compared. two-step method. First CuO nanoparticles were synthesized by co-precipitation method by using Results and Discussion Copper Nitrate precursor and CuO nanoparticles well dispersed in DI water using ultrasonicator. CuO Structural Analysis nanoparticles were characterized by XRD, EDAX The XRD analysis of CuO nanoparticles was and TEM. Experimental Investigation of heat transfer conducted to confirm the crystalline phase and behavior in vertical cylindrical columns, one average particle size was calculated using Scherrer’s containing DI water and other CuO/ DI water formula: nanofluid was done simultaneously with same heat source and the results are compared. where is full width at half maximum (FWHM), Experimentation is the wavelength of X-ray used and is the diffraction angle. Sample preparation Copper Nitrate [Cu(NO3)2.3H2O Merck] was added to a solution containing 500 ml deionized water 600 [Loba chem.] and 1.6 ml glacial acetic acid [CH3COOH Merck]. The obtained 0.2 M blue 500 solution was stirred and heated. When solution temperature was reached 90°C, 8.0M solution of sodium hydroxide [NaOH Merck] was added drop 400 wise to this solution, until the pH of the solution reached 7 and the color of the solution changed from 300 blue to black. The solution is stirred and boiled for 2 hrs, then allowed to cool at room temperature. The 200 solution was centrifuged and obtained CuO black Intensity (a.u.) precipitate; was rinsed thrice with deionized water to remove impurity ions. The CuO precipitate dried at 100 100 °C in hot air oven and ground to get black colored fine powder of CuO nano particles. The 0 chemical reaction is represented as 20 30 40 50 60 70 80 2 Figure 1: XRD pattern of the CuO nanoparticles Page 101 of 104 International Journal of Applied Engineering Research ISSN 0973-4562 Volume 14, Number 13, 2019 (Special Issue) © Research India Publications. http://www.ripublication.com The XRD pattern is shown in the Figure 1 and it reveals the formation of crystalline CuO nanoparticles with monoclinic structure having lattice parameters a=4.689 , b=3.42 and c=5.133 and compared with standard results (JCPDS card no. 80- 1917). All diffraction peaks of the crystalline phase are matching with standard peaks. The broad peaks in XRD pattern indicate the formation of nano sized particles. The particle size is calculated for prominent peaks [(110), (002), (111)] by Scherrer’s formula and it is in the range of 7 to 16 nm. Figure 3: TEM images of CuO nanoparticles Heat transfer analysis The heating experiments were conducted to investigate heat transfer competence of water based CuO nanofluid with 0.07% volume of synthesized CuO nanoparticles in DI water. The experimental set Figure 2: EDAX spectra of CuO nanoparticles up consists of two identical steel vertical cylindrical columns of length 2 m, diameter 2.25 cm with thickness 2 mm. Both the columns were closed at Elemental Analysis bottom and open at top. One of the cylindrical The elemental analysis of CuO nanoparticles was columns was filled with DI water and other one with done by EDAX technique and it is shown in Figure 2. CuO/DI water nanofluid. EDAX revealed that the synthesized CuO Both the columns were heated nanoparticles consist of only Copper and Oxygen simultaneously and indirectly using a same heat with nearly stoichiometric ratio. There were no traces source under same environmental conditions, of any other materials, demonstrating the formation temperature of heater kept constant at 80°C. of pure CuO nanoparticles. The atomic% of Copper Calibrated thermocouples were used to measure and Oxygen calculated from EDAX are 55.61% and temperature of fluid in each cylindrical column at 44.39% respectively. bottom and top to study the relative convective heat transfer of DI water and CuO/ DI water nanofluid. Morphological Analysis Figure 4(a) shows the temperature profile of Figure 3 shows the TEM images of CuO DI water column and CuO/DI water nanofluid nanoparticles