1 Preparation and Characterization of Copper Oxide Nanoparticles and Determination of Enhancement in Critical Heat Flux (original) (raw)
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Thermal Science, 2017
The main focus of the present work is to prepare the CuO nanoparticles by economical Sol-Gel method and further to prepare the CuO nanofluid with base fluid as deionised water. The size of nanoparticles is determined by Debye- Scherer formula and size of the particles is conformed 20.4054nm. Critical heat flux characteristics of nanofluid were investigated with different weight concentrations of CuO nanoparticles. The experimental work revealed an increase in critical heat flux value just about 57.26 percent. Surface roughness of heater surface is measured for all weight concentrations of nanofluid which shows increase in Ra value up to some extent is a cause to enhance CHF.
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.
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.
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.
Inlluence of temperature on thermal conductivity of CuO nanofluid
2010
In the present article we report the synthesis of pure phase of CuO nanoparticles using Cu(NO:)z xH2O as precursor. The technique of synthesis is very fast, cheap and green materials technique. The CUO nanoparticles used in the experiment are rod-like, with a mean length of about 23-26 nm. They can be stably suspended in ethylene glycol for several months. Also stability of nanofluid prepared by such technique is better than that obtained by two step process. The effect of particle volume fraction and temperature on thermal conductivity of CuO-EG nanofluids developed using continuous chemical technique is studied. The thermal conductivity of the nanofluids was studied using the LAMBDA system based on the principle of instationary heat-wire instrument with a very small sensor. The output of the instrument is highly stable and reproducible. Experimental data indicates that the size, volume fraction and properties of nanoparticles (shape, nano layer thickness and material properties) influence the heat transfer characteristics of nanofluids. The experimental results show that the increase in therrnal conductivity with volume fraction is non-linear while that with temperature is linear. Further, the effect of temperature change on the thermal conductivity of nanofluids is greater than that of volume fraction change. For 1.78 percent of the volume fraction the rise in temperature from 25"C to 75oC enhances thermal conductivity by 10.5 percent to 20 percent. Therefore, when the copper oxide nanofluids are applied to the heat exchange device under medium and high temperature, an optimal radiation effect can be acquired.
Experimental and Theoretical NANOTECHNOLOGY
Nanofluids are colloids of nanoparticles in a selected base fluid. The primary application of nanofluid is to increase the heat transfer extent of liquid coolants like water, ethylene glycol, oil etc. In the present work, Copper Oxide (CuO) nanoparticle is prepared by sol-gel technique from CuSO4.5H2O as a precursor material. CuO nanofluids are prepared by two-step method. In the first step, sol-gel synthesis technique is utilized and the second step involves dispersion by ultrasonication. To examine the crystallite size, shape, composition and surface area of prepared CuO nano particles are characterized by XRD, SEM, FTIR, and BET. Further, the heat absorption capacity is also investigated for the prepared CuO-water nanofluid with the varying weight fraction of 0.1, 0.2 and 0.3 in open sunlight. The maximum solar thermal absorption is reported for 0.3wt% CuO-water nanofluid.
ANALYSIS ON FLOW AND HEAT TRANSFER PERFORMANCE OF CUO NANO-FLUID
Heat exchangers are widely used in the heat transfer applications where heat to be rejected or inserted by the system or in to the system. Since past few decades, researchers have found that the rate of heat transfer can be enhance during nano-fluids as they are having better thermophysical properties compared to conventional fluids. Using Two-Step Method, a nano-fluid has been prepared by adding CuO particles into distilled water. The arrangement has been done in such a way that the hot fluid (hot water and nano-fluid) flows through inner pipe and cold water is flowing through the outer pipe. It was detected that the convective heat transfer has improved when CuO-H 2 O nanofluid was used instead of water.
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 ...