Freeze-Thaw Characteristics of Water-Based Copper Oxide Nanofluid (original) (raw)
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Nowadays, it has been proved that changing the thermal characteristics of the fluids is the best solution to increase the rate of heat transfer. To do such a task, using suspended solid particles in a liquid, due to their higher thermal conductivity, can be an appropriate approach. This issue led to introduce a new concept called nanofluids. In this study, water-based nanofluids with CuO nanoparticles were prepared by dispersing nanoparticles using ultrasonic equipment. We prepared nanofluids with various concentrations by adding different particle sizes and various concentrations of surfactant. Thermal conductivities of these nanofluids were measured using the transient Hot-wire method. The main aim of this paper is to survey effects of the most important factors on nanofluids to provide the optimal conditions to achieve the highest thermal conductivity, and also stability of nanofluids; therefore, with the selection of different concentration for water-copper(II) oxide nanofluids as well as changes of pH values, it was determined that an aqueous nanofluid containing 1wt% CuO nanoparticles and pH=4 with the particle diameter of 20 nmexhibited a thermal conductivity about 47% greater than that of water. This nanofluid was chosen as the optimal nanofluid due to its thermal characteristics and desirable stability.
Synthesis and Charecterization of Copper oxide –Water Based Nanofluid For Heat Transfer Applications
2019
The objective of the current research is to prepare copper oxide water based nanofluid for heat transfer application. The present work reports synthesis of nanocrystalline copper oxide using surfactant assisted wet chemical method. The average crystallite size of the copper oxide nanoparticles was calculated using XRD as 14 (±2) nm. The copper oxide-water based nanofluid was prepared using ultrasonic sonication method for potential use as a coolant for heat transfer applications. The heat transfer characteristics (thermal conductivity, specific heat and viscosity) of copper oxide nanofluid were determined using experimental set up as designed in the laboratory. The enhancement of thermal conductivity was observed as 20 % more compared to the earlier reported values for 0.1% volume concentration. This is an achievement of the present work.
Investigation of Heat Transfer Coefficients for CuO Based Nanofluids
2018
Experimental data with CuO nanoparticles dispersed in water and ethylene glycol water mixture ratios of 60:40 (EG-W 60-40) was available in literature. Theoretical analysis have been undertaken in the turbulent range of Reynolds number to determine the effect of liquid mixture ratio on thermal properties, heat transfer coefficients and enhancement ratio. The heat transfer coefficients with EG-W 60-40 mixture ratio is greater than the values with water. Temperature effect and concentration effect on heat transfer coefficients of nanofluids were analyzed and observed that heat transfer coefficient increases with concentration and decreases with temperature.
Heat Transfer of Cuo-Water Based Nanofluids in a Compact Heat Exchanger
2015
and the operating temperatures on the rate of nanofluids heat transfer in a compact heat exchanger. 40 nm CuO nanoparticles was mixed with demineralized water at 2% and 6% volume concentrations. Sodium Lauryl Sulphate (SLS) powder was added to enhance the mixing process and stabilize the dispersion of the nanofluids. A custom-made closed loop test rig were designed, fabricated and tested for these experiments. The test rig was set-up to represent the actual ap-plication of the nanofluids in cooling of a compact heat exchanger. Experimental runs were conducted at varying operating temperatures which include the runs for water, CuO-water at 40 o C, 50 o C and 60 o C. The results indicate that by adding small amount of CuO nanoparticles into water as the base fluid, the rate of heat transfer and convection heat transfer coefficient would increases by at least 17.3% and 40% respectively. It was also discovered that CuO nanofluids with 2% volume loading produces greater increase in rate ...
International Communications in Heat and Mass Transfer, 2018
In this study, the effect of temperature and mass fraction of Al 2 O 3 and WO 3 nanoparticles dispersed in deionized water and liquid paraffin was investigated on dynamic viscosity of nanofluid. The results of the TEM tests showed that the size of Al 2 O 3 and WO 3 nanoparticles was ranged from 10 to 60 nm, and the results showed that nanoparticles were semi-spherical. Also the results of DLS and zeta potential tests, respectively, exhibited the uniform size and high stability of the nanoparticles in the basefluid environment. The findings showed that adding a certain amount of nanoparticles to water and liquid paraffin increases dynamic viscosity, and in the case of various shear rates, the viscosity is constant for the waterbased nanofluids, which indicates the Newtonian behavior of the nanofluid. In addition, for those prepared by liquid paraffin as a basefluid, the viscosity does not remain constant at different shear rates and at low amount of shear rate the viscosity achieves higher value, indicating non-Newtonian behavior of liquid paraffin-based nanofluids. The results showed that by increasing the temperature in liquid paraffin-based nanofluid the uniformity and linearity of the viscosity curve at various shear rates could be observed, which represents an approach for Newtonian behavior of nanofluid at higher temperatures. These results also showed that with increasing the mass fraction of nanoparticles in water and liquid paraffin, the viscosity increases at different shear rates. Finally, the correlation presented in this study shows that for nanofluid viscosity as a function of nanoparticles load and temperature, the deviation of correlated data from experimental values is less than 10%.
Particle size effects in the thermal conductivity enhancement of copper-based nanofluids
Nanoscale Research Letters, 2011
We present an analysis of the dispersion characteristics and thermal conductivity performance of copper-based nanofluids. The copper nanoparticles were prepared using a chemical reduction methodology in the presence of a stabilizing surfactant, oleic acid or cetyl trimethylammonium bromide (CTAB). Nanofluids were prepared using water as the base fluid with copper nanoparticle concentrations of 0.55 and 1.0 vol.%. A dispersing agent, sodium dodecylbenzene sulfonate (SDBS), and subsequent ultrasonication was used to ensure homogenous dispersion of the copper nanopowders in water. Particle size distribution of the copper nanoparticles in the base fluid was determined by dynamic light scattering. We found that the 0.55 vol.% Cu nanofluids exhibited excellent dispersion in the presence of SDBS. In addition, a dynamic thermal conductivity setup was developed and used to measure the thermal conductivity performance of the nanofluids. The 0.55 vol.% Cu nanofluids exhibited a thermal conductivity enhancement of approximately 22%. In the case of the nanofluids prepared from the powders synthesized in the presence of CTAB, the enhancement was approximately 48% over the base fluid for the 1.0 vol.% Cu nanofluids, which is higher than the enhancement values found in the literature. These results can be directly related to the particle/agglomerate size of the copper nanoparticles in water, as determined from dynamic light scattering.
International Communications in Heat and Mass Transfer, 2012
In this paper the effect of CuO nanoparticles on the thermal conductivity of base fluids like mono ethylene glycol and water was studied. Both the base fluids showed enhancement in effective thermal conductivity. This enhancement was investigated with regard to various factors; concentration of nanoparticles, types of base fluids, sonication time and settlement time. For both the base fluids, an improvement in thermal conductivity was found as concentration of nanoparticles increased due to interaction between particles. It was also found that as the sonication time was increased, there was furthermore an improvement in the thermal conductivity of the base fluids. Effect of base fluids is the complex idea to understand. Lower base fluid's viscosities are supposed to contribute grater enchantment, but another factor of fluid nanoparticles surface interaction also more important. The experimentally measured thermal conductivities of base fluid's nanoparticles suspension were compared to a variety of models (Maxwell, Hamilton-Crosser and Bruggeman Model). It is observed that none of the mentioned models were found to predict accurately the thermal conductivities of nanofluids.
Studies on the High Thermal Conduction Fluid by Incorporating CuO Nanoparticles in a Liquid Coolant
Materials Today: Proceedings, 2019
CuO nanoparticles have shown a high level of interest in the field of nanoscience and nanotechnology as these possess an ability to change material's properties drastically when incorporated in the matrix. The present work is deemed to the synthesis of highly pure copper oxide nanoparticles (CuO) via reflux condensation method and their use as nanofluid for high thermal conduction applications. The synthesized CuO nanoparticles have been characterized by X-ray diffraction technique (XRD), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDAX) and thermogravimetric analysis (TGA). XRD technique shows the crystallite size of CuO nanoparticles of 8-17 nm, the particle size of CuO nanoparticles are 8-19 nm and the shape of nanoparticles are spherical as obtained from TEM analysis. Thermal stability of nanoparticles is analyzed by TGA, no significant loss is found in the range of 100-600 °C. EDAX gives the purity of the CuO nanoparticles. Since CuO nanoparticles have shown a high thermal energy rejection, it is thought to give faster heat rejection from the heat sink to the environment. The studies were conducted on the change in the thermal conduction of a liquid system to the environment with respect to the weight of nanoparticles dispersed in a fluid. The liquid and nanofluids were characterized for thermal conduction measurement by KD2 pro thermal analyzer. Satisfactory results have been obtained from the study show that the CuO nanoparticles increase the thermal conduction of a coolant by increasing its effectiveness and behave as an ideal coolant.
ScienceDirect, 2016
This study presents an experimental study of the effect of solid volume fraction and Reynolds number on heat transfer coefficient and pressure drop of CuO-Water nanofluid. Pure Water and nanofluid with particle volume fractions of 0.0625%, 0.125%, 0.25%, 0.5%, 1%, 1.5% and 2% are used as working fluids. Nanofluids were flowed inside a horizontal double-tube counter flow heat exchanger under turbulent flow regime. Flow Reynolds numbers of each volume fraction of nanofluid were between from 2900 to 18,500 during the experiments. The Result shows that generally heat transfer coefficient of nanofluids is higher than that of base fluid. Moreover, it is observed that heat transfer coefficient and Nusselt number of nanofluids increases with an increase in solid volume fraction and Reynolds number. But the rate of this increase in low Reynolds numbers was more than that at high Reynolds numbers. The measurements also show that the pressure drop of nanofluid is slightly higher than that of the base fluid and increases with an increase in the nanoparticles volume fraction. But the rate of this increase in low Reynolds numbers was more than that at high Reynolds numbers. Therefore, it can be concluded that the effect of increasing percentage of nanoparticle in low Reynolds number of this research is stronger than that of high Reynolds number. Moreover, friction factors were calculated and compared with blasious correlation. Finally, in order to find the optimum condition of this nanofluid for practical applications, thermal performance factor was defined to consider increasing Nusselt ratio besides increasing friction ratio simultaneously. The results show that the maximum thermal performance factor of this nanofluid was 1.266, which was calculated for 2% nanoparticle volume fraction at Reynolds number 3677.