EXPERIMENTAL AND NUMERICAL INVESTIGATION OF HEAT TRANSFER AUGMENTATION USING AL2O3-ETHYLENE GLYCOL NANOFLUIDS UNDER TURBULENT FLOWS IN A FLAT TUBE

2016 ◽  
Vol 78 (9-2) ◽  
Author(s):  
M. Kh. Abdolbaqi ◽  
Nor Azwadi Che Sidik ◽  
Muhammad Noor Afiq Witri Muhammad Yazid ◽  
Rizalman Mamat ◽  
W. H. Azmi ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Friction Factor ◽  
Turbulent Flows ◽  
Volume Concentration ◽  
Three Dimensional ◽  
Hydrodynamic Performance ◽  
Homogeneous Fluid ◽  
Flat Tube ◽  
Fluid Behaviour

A study of computational fluid dynamics has been conducted to study the characteristics of the heat transfer and friction factor of Al2O3/Ethylene glycol-water nanofluid flowing inside flat tube. The three dimensional realizable k–e turbulent model with an enhanced wall treatment was utilized. The evaluation of the overall performance of the tested tube was predicated on the thermo-hydrodynamic performance index. The obtained results showed that the difference in behaviour depending on the parameter that has been selected to compare the nanofluid with the base fluid. In addition, the friction factor and the heat transfer coefficient increases with an increase of the nanoparticles volume concentration at the same Reynolds number. The penalty of pressure drop is negligible with an increase of the volume concentration of nanoparticles. Conventional correlations that have been used in turbulent flow regime to predict average heat transfer and friction factor are Dittus-Boelter and Blasius correlations, for tubes are also valid for the tested nanofluids which consider that the nanofluids have a homogeneous fluid behaviour.

scholarly journals Experimental and Numerical investigation of Heat transfer enhancement using Al2O3-Ethylene Glycol/Water nanofluids in straight channel

2018 ◽  
Vol 225 ◽  
pp. 01019 ◽  
Author(s):  
Mohammed K. Mohammed ◽  
M. Kh Abdolbaqi ◽  
Thamir K. Ibrahim ◽  
Rizalman Bin Mamat ◽  
Omar I. Awad
Keyword(s):  
Heat Transfer ◽  
Ethylene Glycol ◽  
Friction Factor ◽  
Volume Concentration ◽  
Three Dimensional ◽  
Straight Channel ◽  
Temperature Dependent ◽  
Homogeneous Fluid ◽  
Turbulent Flow Regime ◽  
The Difference

A study of computational fluid dynamics has been conducted to study the characteristics of the heat transfer and friction factor of Al2O3/Ethylene glycol-water nanofluid flowing in straight channel. The three dimensional realizable k-e turbulent model with enhanced wall treatment was utilized. As well as were used Temperature dependent thermophysical properties of nanofluid and water. The evaluation of the overall performance of the tested channel was predicated on the thermohydrodynamic performance index. The obtained results showed that the difference in behaviour depending on the parameter that has been selected to compare the nanofluid with the base fluid. In addition, the friction factor and the heat transfer coefficient increases with an increase of the nanoparticles volume concentration at the same Reynolds number. The penalty of pressure drop is negligible with an increase of the volume concentration of nanoparticles. Conventional correlations that have been used in turbulent flow regime to predict average heat transfer and friction factor are Dittus-Boelter and Blasius correlations, for channel are also valid for the tested nanofluids which consider that the nanofluids have a homogeneous fluid behave.

scholarly journals The Effect of Nanofluid Volume Concentration on Heat Transfer and Friction Factor inside a Horizontal Tube

2013 ◽  
Vol 2013 ◽  
pp. 1-12 ◽  
Author(s):  
Adnan M. Hussein ◽  
K. V. Sharma ◽  
R. A. Bakar ◽  
K. Kadirgama
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Nusselt Number ◽  
Thermal Properties ◽  
Friction Factor ◽  
Volume Concentration ◽  
Convection Heat Transfer ◽  
Horizontal Tube ◽  
Maximum Deviation ◽  
Flat Tube

The additives of solid nanoparticles to liquids are significant enhancement of heat transfer and hydrodynamic flow. In this study, the thermal properties of three types of nanoparticles (Al2O3, TiO2, and SiO2) dispersed in water as a base fluid were measured experimentally. Forced convection heat transfer turbulent flow inside heated flat tube was numerically simulated. The heat flux around flat tube is 5000 W/m2and Reynolds number is in the range of5×103to50×103. CFD model by finite volume method used commercial software to find hydrodynamic and heat transfer coefficient. Simulation study concluded that the thermal properties measured and Reynolds number as input and friction factor and Nusselt number as output parameters. Data measured showed that thermal conductivity and viscosity increase with increasing the volume concentration of nanofluids with maximum deviation 19% and 6%, respectively. Simulation results concluded that the friction factor and Nusselt number increase with increasing the volume concentration. On the other hand, the flat tube enhances heat transfer and decreases pressure drop by 6% and −4%, respectively, as compared with circular tube. Comparison of numerical analysis with experimental data available showed good agreement with deviation not more than 2%.

Heat Transfer Performance of Different Nanofluids Flows in a Helically Coiled Heat Exchanger

2013 ◽  
Vol 832 ◽  
pp. 160-165 ◽  
Author(s):  
Mohammad Alam Khairul ◽  
Rahman Saidur ◽  
Altab Hossain ◽  
Mohammad Abdul Alim ◽  
Islam Mohammed Mahbubul
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Coefficient ◽  
Heat Exchanger ◽  
Pressure Drop ◽  
Transfer Coefficient ◽  
Friction Factor ◽  
Heat Exchangers ◽  
Heat Transfer Performance ◽  
Volume Concentration ◽  
Transfer Performance

Helically coiled heat exchangers are globally used in various industrial applications for their high heat transfer performance and compact size. Nanofluids can provide excellent thermal performance of this type of heat exchangers. In the present study, the effect of different nanofluids on the heat transfer performance in a helically coiled heat exchanger is examined. Four different types of nanofluids CuO/water, Al2O3/water, SiO2/water, and ZnO/water with volume fractions 1 vol.% to 4 vol.% was used throughout this analysis and volume flow rate was remained constant at 3 LPM. Results show that the heat transfer coefficient is high for higher particle volume concentration of CuO/water, Al2O3/water and ZnO/water nanofluids, while the values of the friction factor and pressure drop significantly increase with the increase of nanoparticle volume concentration. On the contrary, low heat transfer coefficient was found in higher concentration of SiO2/water nanofluids. The highest enhancement of heat transfer coefficient and lowest friction factor occurred for CuO/water nanofluids among the four nanofluids. However, highest friction factor and lowest heat transfer coefficient were found for SiO2/water nanofluids. The results reveal that, CuO/water nanofluids indicate significant heat transfer performance for helically coiled heat exchanger systems though this nanofluids exhibits higher pressure drop.

scholarly journals Experimental Investigation of Thermo-Physical Properties of Tri-Hybrid Nanoparticles in Water-Ethylene Glycol Mixture

2021 ◽  
Vol 18 (8) ◽  
Author(s):  
Anwar Ilmar RAMADHAN ◽  
Wan Hamzah AZMI ◽  
Rizalman MAMAT
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Ethylene Glycol ◽  
Physical Properties ◽  
Dynamic Viscosity ◽  
Volume Concentration ◽  
Hybrid Nanoparticles ◽  
Maximum Enhancement ◽  
Hybrid Nanofluids ◽  
Thermo Physical Properties

In recent years, research has focused on enhancing the thermo-physical properties of a single component nanofluid. Therefore, hybrid or composite nanofluids have been developed to improve heat transfer performance. The thermo-physical properties of the Al2O3-TiO2-SiO2 nanoparticles suspended in a base of water (W) and ethylene glycol (EG) at constant volume ratio of 60:40 and different volume concentrations were investigated. The experiment was conducted for the volume concentrations of 0.05, 0.1, 0.2, and 0.3% of Al2O3-TiO2-SiO2 nanofluids at different temperatures of 30, 40, 50, 60, and 70 °C. Thermal conductivity and dynamic viscosity measurements were carried out at temperatures ranging from 30 to 70 °C by using KD2 Pro Thermal Properties Analyzer and Brookfield LVDV III Ultra Rheometer, respectively. The highest thermal conductivity for tri-hybrid nanofluids was obtained at 0.3% volume concentration, and the maximum enhancement was increased up to 9% higher than the base fluid (EG/W). Tri-hybrid nanofluids with a volume concentration of 0.05% gave the lowest effective thermal conductivity of 4.8 % at 70 °C temperature. Meanwhile, the dynamic viscosity of the tri-hybrid nanofluids was influenced by volume concentration and temperature. Furthermore, tri-hybrid nanofluids behaved as a Newtonian fluid for volume concentrations from 0.05 to 3.0%. The properties enhancement ratio (PER) estimated that the tri-hybrid nanofluids will aid in heat transfer for all samples in the present. The new correlations for thermal conductivity and dynamic viscosity of tri-hybrid nanofluids were developed with minimum deviation. As a conclusion, the combination of the enhancement in thermal conductivity and dynamic viscosity for tri-hybrid at 0.3% volume concentration was found the optimum condition with more advantage for heat transfer than other concentrations.

Fluid Flow and Heat Transfer Behavior for Turbulent Flows in a Tube With Vortex Generator Pairs for an Efficient Heat Exchanger

2018 ◽  
Author(s):  
Md. Islam ◽  
Z. Chong ◽  
S. Bojanampati
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Friction Factor ◽  
Turbulent Flows ◽  
Flow Behavior ◽  
Vortex Generator ◽  
Tube Diameter ◽  
Vortex Generators ◽  
Blockage Ratio ◽  
Delta Winglet

Various technologies have been developed to enhance flow mixing and heat transfer in order to develop an efficient compact heat exchanging devices. Vortex generators/turbulent promoters generate the vortices which reduce the boundary layer thickness and introduce the better mixing of the fluid to enhance the heat transfer. In this research experimental investigations have been carried out to study the effect of delta winglet vortex generator pairs on heat transfer and flow behavior. To generate longitudinal vortex flow, two pairs of the delta winglet vortex generators (DWVG) with the length of 10mm and winglet-pitch to tube-diameter ratio (PR = 4.8) are mounted on the inner wall of a circular tube. The DWVG pairs with two different winglet-height to tube-diameter ratios (Blockage ratio, BR = 0.1 and 0.2), three attack angles (α = 10°, 20°, 30°) and three spacings between leading edges (S = 10, 15 and 20mm) are studied. The experiments were conducted with DWVGs pairs for the air flow range of Reynolds numbers 5000–25000. The influence of the DWVGs on heat transfer and pressure drop was investigated in terms of the Nusselt number and friction factor. The experimental results indicate that DWVG pair in a tube results in a considerable enhancement in Nusselt number (Nu) with some pressure penalty. It is found that DWVG increases Nu up to 85% over the smooth tube. It is also observed that Nusselt number increases with Re, blockage ratio and attack angle. Friction factor decreases with Re but increases with blockage ratio, spacing and attack angle. And 30° DWVG pair with S = 20mm, BR = 0.2 gets the highest friction factor. The Highest thermal performance enhancement (TPE) was noticed for α = 10°, S = 20mm, BR = 0.2 for turbulent flows. To obtain qualitative information on the flow behavior and vortex structures, flow was visualized by laser sheet using smoke as a tracer supplied at the entrance of the test section. The generation and development of longitudinal vortices influenced by DWVG pairs were clearly observed.

Effect of Non Uniform Flow Distribution on Single Phase Heat Transfer in Parallel Microchannels

2007 ◽  
Author(s):  
Akhilesh V. Bapat ◽  
Satish G. Kandlikar
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Single Phase ◽  
Flow Distribution ◽  
Uniform Flow ◽  
Hydrodynamic Performance ◽  
Flow Area ◽  
Cross Sectional ◽  
Uniform Flow Distribution ◽  
Parallel Microchannels

The continuum assumption has been widely accepted for single phase liquid flows in microchannels. There are however a number of publications which indicate considerable deviation in thermal and hydrodynamic performance during laminar flow in microchannels. In the present work, experiments have been performed on six parallel microchannels with varying cross-sectional dimensions. A careful assessment of friction factor and heat transfer in is carried out by properly accounting for flow area variations and the accompanying non-uniform flow distribution in individual channels. These factors seem to be responsible for the discrepancy in predicting friction factor and heat transfer using conventional theory.

Effects of Al2O3–Cu/water hybrid nanofluid on heat transfer and flow characteristics in turbulent regime

2015 ◽  
Vol 26 (04) ◽  
pp. 1550047 ◽  
Author(s):  
Behrouz Takabi ◽  
Hossein Shokouhmand
Keyword(s):  
Heat Transfer ◽  
Friction Factor ◽  
Pure Water ◽  
Flow Characteristics ◽  
Hydrodynamic Performance ◽  
Hybrid Nanofluid ◽  
Turbulent Regime ◽  
Average Increase ◽  
Finite Volume Discretization ◽  
Wide Range

In this paper, forced convection of a turbulent flow of pure water, Al 2 O 3/water nanofluid and Al 2 O 3– Cu /water hybrid nanofluid (a new advanced nanofluid composited of Cu and Al 2 O 3 nanoparticles) through a uniform heated circular tube is numerically analyzed. This paper examines the effects of these three fluids as the working fluids, a wide range of Reynolds number (10 000 ≤ Re ≤ 10 0000) and also the volume concentration (0% ≤ ϕ ≤ 2%) on heat transfer and hydrodynamic performance. The finite volume discretization method is employed to solve the set of the governing equations. The results indicate that employing hybrid nanofluid improves the heat transfer rate with respect to pure water and nanofluid, yet it reveals an adverse effect on friction factor and appears severely outweighed by pressure drop penalty. However, the average increase of the average Nusselt number (when compared to pure water) in Al 2 O 3– Cu /water hybrid nanofluid is 32.07% and the amount for the average increase of friction factor would be 13.76%.

scholarly journals Heat transfer intensification of Zirconia/water nanofluid

2017 ◽  
Vol 13 ◽  
pp. 01-08
Author(s):  
Mohamed Iqbal Shajahan ◽  
Chockalingam Sundar Raj ◽  
Sambandan Arul ◽  
Palanisamy Rathnakumar
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Laminar Flow ◽  
Friction Factor ◽  
Volume Concentration ◽  
Constant Heat Flux ◽  
Particle Volume ◽  
Heat Transfer Intensification ◽  
Nusselt Numbers ◽  
Thermal Analyser

This paper investigated convective heat transfer and friction factor of ZrO2/H2O nanofluid through a circular pipe under laminar flow condition with constant heat flux. Nanofluid is prepared for 0.5, 0.75 and 1% volume concentrations with yttrium oxide surfactant. Nanofluid’s thermal conductivity and viscosity is measured by KD2 Pro thermal analyser and Brookfield viscometer respectively. Results showed that the thermal conductivity and viscosity increased with increase in particle volume concentration. These nanofluids are experimented in a forced convection system, first heat transfer characteristics of DI (Deionised) water  under laminar flow in a copper tube measured, then three nanofluids are carried out the tests, results revealed that the enhanced Nusselt numbers of 21.09,28.05 and 35.73%  at the 0.5, 0.75 and 1% volume concentrations, There is no excess penalty in pumping power  and results showed  less variations in friction factor for nanofluids comparatively with the base fluid DIWater.

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