CFD Investigation of Al2O3 Nanoparticles Effect on Heat Transfer Enhancement of Newtonian and Non-Newtonian Fluids in a Helical Coil

2019 ◽  
Vol 14 (3) ◽  
Author(s):  
Javad Aminian Dehkordi ◽  
Arezou Jafari
Keyword(s):  
Heat Transfer ◽  
Aqueous Solution ◽  
Nusselt Number ◽  
Base Fluid ◽  
Volume Fraction ◽  
Reynolds Numbers ◽  
Helical Coil ◽  
Al2o3 Nanoparticles ◽  
Nanoparticles Volume Fraction ◽  
Computational Fluid Dynamics Cfd

Abstract The present study applied computational fluid dynamics (CFD) to investigate the heat transfer of Newtonian (water) and non-Newtonian (0.3 %wt. aqueous solution of carboxymethylcellulose (CMC)) fluids in the presence of Al2O3 nanoparticles. To analyze the heat transfer rate, investigations were performed in a vertical helical coil as essential heat transfer equipment, at different inlet Reynolds numbers. To verify the accuracy of the simulation model, experimental data reported in the literature were employed. Comparisons showed the validity of simulation results. From the results, compared to the aqueous solution of CMC, water had a higher Nusselt number. In addition, it was observed that adding nanoparticles to a base fluid presented different results in which water/Al2O3 nanofluid with nanoparticles’ volume fraction of 5 % was more effective than the same base fluid with a volume fraction of 10 %. In lower ranges of Reynolds number, adding nanoparticles was more effective. For CMC solution (10 %), increasing concentration of nanoparticles caused an increase in the apparent viscosity. Consequently, the Nusselt number was reduced. The findings reveal the important role of fluid type and nanoparticle concentration in the design and development of heat transfer equipment.

Study of the boundary layer heat transfer of nanofluids over a stretching sheet: Passive control of nanoparticles at the surface

2015 ◽  
Vol 93 (7) ◽  
pp. 725-733 ◽  
Author(s):  
M. Ghalambaz ◽  
E. Izadpanahi ◽  
A. Noghrehabadi ◽  
A. Chamkha
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Heat Transfer Enhancement ◽  
Base Fluid ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Enhancement Ratio ◽  
Transfer Enhancement

The boundary layer heat and mass transfer of nanofluids over an isothermal stretching sheet is analyzed using a drift-flux model. The relative slip velocity between the nanoparticles and the base fluid is taken into account. The nanoparticles’ volume fractions at the surface of the sheet are considered to be adjusted passively. The thermal conductivity and the dynamic viscosity of the nanofluid are considered as functions of the local volume fraction of the nanoparticles. A non-dimensional parameter, heat transfer enhancement ratio, is introduced, which shows the alteration of the thermal convective coefficient of the nanofluid compared to the base fluid. The governing partial differential equations are reduced into a set of nonlinear ordinary differential equations using appropriate similarity transformations and then solved numerically using the fourth-order Runge–Kutta and Newton–Raphson methods along with the shooting technique. The effects of six non-dimensional parameters, namely, the Prandtl number of the base fluid Prbf, Lewis number Le, Brownian motion parameter Nb, thermophoresis parameter Nt, variable thermal conductivity parameter Nc and the variable viscosity parameter Nv, on the velocity, temperature, and concentration profiles as well as the reduced Nusselt number and the enhancement ratio are investigated. Finally, case studies for Al2O3 and Cu nanoparticles dispersed in water are performed. It is found that increases in the ambient values of the nanoparticles volume fraction cause decreases in both the dimensionless shear stress f″(0) and the reduced Nusselt number Nur. Furthermore, an augmentation of the ambient value of the volume fraction of nanoparticles results in an increase the heat transfer enhancement ratio hnf/hbf. Therefore, using nanoparticles produces heat transfer enhancement from the sheet.

scholarly journals Numerical study of heat transfer enhancement in the entrance region for low-pressure gaseous laminar pipe flows using Al2O3–air nanofluid

2018 ◽  
Vol 10 (7) ◽  
pp. 168781401878441 ◽  
Author(s):  
Wael Al-Kouz ◽  
Rafat Al-Waked ◽  
Ma’en Sari ◽  
Wahib Owhaib ◽  
Anas Atieh
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Aspect Ratio ◽  
Knudsen Number ◽  
Average Nusselt Number ◽  
Volume Fraction ◽  
Low Pressure ◽  
Entrance Region ◽  
Physical Parameters ◽  
Nanoparticles Volume Fraction

The gaseous low-pressure nanofluid flow of a steady-state two-dimensional laminar forced convection heat transfer in the entrance region of pipes is numerically investigated. Such flows are of interest for many engineering applications like the nuclear reactor and electronic equipment cooling, heat exchangers, and many others. Physical parameters considered in this study are Reynolds number ( Re), Prandtl number ( Pr), nanosolid particles volume fraction [Formula: see text], Knudsen number ( Kn), and the aspect ratio ( AR). These parameters ranges are as follows: [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text]. The outcome of this study shows that by increasing Kn, velocity slip and temperature jump at the solid boundaries increase. In addition, heat transfer is enhanced by dispersing Al2O3 nanoparticles in the base low-pressure gaseous flow. Results show that there is no effect of the nanoparticles volume fraction with values below 0.03 on the average Nusselt number. The average Nusselt number increases [Formula: see text] as the value of the nanoparticles volume fraction exceeds 0.03. For instance, at Re = 1000, results show that when dispersing Al2O3 nanosolid particles with volume fractions of 0.3 and 0.5; there is an enhancement in the average Nusselt number of 30.35% and 136.74%, respectively, when compared to the case of dispersing Al2O3 nanosolid particles of 0.03 volume fraction.. Moreover, it is concluded that the average Nusselt number [Formula: see text] depends directly on Reynolds ( Re), Prandtl ( Pr) numbers, and the nanoparticles volume fraction [Formula: see text] and inversely on Knudsen number ( Kn) and the aspect ratio ( AR) for the investigated range of parameters considered in this study. Finally, a correlation of Nusselt number among all the investigated parameters in this study is proposed as [Formula: see text].

scholarly journals Numerical Investigation of Heat Transfer Enhancement in a Rectangular Heated Pipe for Turbulent Nanofluid

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Hooman Yarmand ◽  
Samira Gharehkhani ◽  
Salim Newaz Kazi ◽  
Emad Sadeghinezhad ◽  
Mohammad Reza Safaei
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Volume Fraction ◽  
Rectangular Channel ◽  
Thermal Characteristics ◽  
Reynolds Numbers ◽  
Constant Heat Flux ◽  
Energy Equations ◽  
Volume Method ◽  
Good Agreement

Thermal characteristics of turbulent nanofluid flow in a rectangular pipe have been investigated numerically. The continuity, momentum, and energy equations were solved by means of a finite volume method (FVM). The symmetrical rectangular channel is heated at the top and bottom at a constant heat flux while the sides walls are insulated. Four different types of nanoparticles Al2O3, ZnO, CuO, and SiO2at different volume fractions of nanofluids in the range of 1% to 5% are considered in the present investigation. In this paper, effect of different Reynolds numbers in the range of 5000 < Re < 25000 on heat transfer characteristics of nanofluids flowing through the channel is investigated. The numerical results indicate that SiO2-water has the highest Nusselt number compared to other nanofluids while it has the lowest heat transfer coefficient due to low thermal conductivity. The Nusselt number increases with the increase of the Reynolds number and the volume fraction of nanoparticles. The results of simulation show a good agreement with the existing experimental correlations.

scholarly journals Control of the free convective heat transfer using a U-shaped obstacle in an Al2O3-water nanofluid filled cubic cavity

2021 ◽  
Vol 8 (7) ◽  
pp. 23-30
Author(s):  
Rajab Al-Sayagh ◽  
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Rayleigh Number ◽  
Free Convection ◽  
Convective Heat Transfer ◽  
Volume Fraction ◽  
Temperature Fields ◽  
Flow Structures ◽  
Nanoparticles Volume Fraction ◽  
Al2o3 Nanofluid

This paper deals with the study of free convection in a 3D enclosure filled with Al2O3-nanofluid and equipped with a U-shaped obstacle. The used U-shaped obstacle is considered perfectly conductive. The effect of the dimension and the orientation of the obstacle is investigated. In addition, the parameters governing the problem are varied as Rayleigh number (103 to 106), and nanoparticles volume fraction (0 to 7.5%). Results are depicted in terms of flow structures, temperature fields, and Nusselt number. Results show that the obstacle dimension and orientation can control the flow and optimize the heat transfer and the addition of nanoparticles enhances significantly Nusselt number.

Three-Dimensional Numerical Simulation of Mixed Convective Heat Transfer in a Horizontal Rectangular Duct Utilizing Nanofluids

2014 ◽  
Vol 1016 ◽  
pp. 738-742
Author(s):  
Nur Irmawati Om ◽  
H.A. Mohammed
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Aspect Ratio ◽  
Convective Heat Transfer ◽  
Convective Heat ◽  
Volume Fraction ◽  
Three Dimensional ◽  
Rectangular Duct ◽  
Thermal Fields ◽  
Nanoparticles Volume Fraction

Predictions are reported for three-dimensional laminar mixed convective heat transfer using nanofluids in a horizontal rectangular duct. Five different types of nanoparticle, Ag, Al2O3, Au, Cu and SiO2 with nanoparticles volume fractions range of 2% to 10% are investigated. In this study, the effects of nanofluids type, nanoparticles volume fraction of nanofluids and the effect of aspect ratio on the thermal fields were examined. Results reveal that the addition of nanoparticles to the base fluid and their volume fraction tend to increase the Nusselt number along the horizontal rectangular duct (i.e., increases the rate of heat transfer). It was also found that the Nusselt number increases as the aspect ratio decreases.

scholarly journals Heat Transfer of Oil/MWCNT Nanofluid Jet Injection Inside a Rectangular Microchannel

Symmetry ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 757 ◽  
Author(s):  
Esmaeil Jalali ◽  
Omid Ali Akbari ◽  
M. M. Sarafraz ◽  
Tehseen Abbas ◽  
Mohammad Reza Safaei
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Base Fluid ◽  
Volume Fraction ◽  
Heated Surface ◽  
Fluid Velocity ◽  
Fluid Temperature ◽  
Jet Injection ◽  
Rectangular Microchannel ◽  
Volume Fractions

In the current study, laminar heat transfer and direct fluid jet injection of oil/MWCNT nanofluid were numerically investigated with a finite volume method. Both slip and no-slip boundary conditions on solid walls were used. The objective of this study was to increase the cooling performance of heated walls inside a rectangular microchannel. Reynolds numbers ranged from 10 to 50; slip coefficients were 0.0, 0.04, and 0.08; and nanoparticle volume fractions were 0–4%. The results showed that using techniques for improving heat transfer, such as fluid jet injection with low temperature and adding nanoparticles to the base fluid, allowed for good results to be obtained. By increasing jet injection, areas with eliminated boundary layers along the fluid direction spread in the domain. Dispersing solid nanoparticles in the base fluid with higher volume fractions resulted in better temperature distribution and Nusselt number. By increasing the nanoparticle volume fraction, the temperature of the heated surface penetrated to the flow centerline and the fluid temperature increased. Jet injection with higher velocity, due to its higher fluid momentum, resulted in higher Nusselt number and affected lateral areas. Fluid velocity was higher in jet areas, which diminished the effect of the boundary layer.

scholarly journals Analysis of Platelet Shape Al2O3 and TiO2 on Heat Generative Hydromagnetic Nanofluids for the Base Fluid C2H6O2 in a Vertical Channel of Porous Medium

2021 ◽  
Vol 18 (14) ◽  
Author(s):  
Silpi HAZARIKA ◽  
Sahin AHMED ◽  
Ali J. CHAMKHA
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Porous Medium ◽  
Heat Generation ◽  
Base Fluid ◽  
Volume Fraction ◽  
Metal Oxide Nanoparticles ◽  
Oxide Nanoparticles ◽  
Nanoparticles Volume Fraction ◽  
Platelet Shape

An analytical investigation is performed on the unsteady hydromagnetic flow of nanoparticles Al2O3 and TiO2 in the EG base fluid through a saturated porous medium bounded by two vertical surfaces with heat generation and no-slip boundary conditions. The physics of initial and boundary conditions is designated with the flow model's non-linear partial differential equations. The analytical expressions of nanofluid velocity and temperature with the channel are derived, and Matlab Codes are used to plot the significant results for physical variables. From the physical point of view for nanofluid velocity and temperature results, the base fluid C2H6O2 has a higher viscosity and thermal conductivity than that of water. Physically, the platelet shape Al2O3 nanofluid has the highest velocity than TiO2 nanofluid. It is found that the velocity of nanofluid enhanced the porosity and nanoparticles volume fraction for Al2O3 - EG and TiO2 - EG base nanofluids. However, this trend is reversed for the effects of heat generation. Obtained results indicate that an increase in nanoparticles volume fraction raises the skin friction near the surface, but profiles gradually become linear, due to less frictional effects of nanoparticles. Moreover, due to higher values of nanoparticles volume fraction, the thermal conductivity is raised, and thus the thickness of the thermal boundary layer is declined. The results show that the method provides excellent approximations to the analytical solution of nonlinear system with high accuracy. Metal oxide nanoparticles have wide applications in various fields due to their small sizes, such as the pharmaceutical industry and biomedical engineering. HIGHLIGHTS Impact of platelet shape Al2O3 and TiO2 for base fluid C2H6O2 is studied In Couette and Poiseuille flow, nanoparticles play a vital role to enhance the heat transfer The infinite series solution has been used for solving the non-linear PDE’s The uses of Al2O3 and TiO2 in significant heat transfer applications is overviewed The physiochemical and structural features of metal oxide nanoparticles have diverse biomedical applications GRAPHICAL ABSTRACT

scholarly journals Numerical Simulation of Laminar Flow and Heat Transfer of a Non-Newtonian Nanofluid in an Agitated Tank

2021 ◽  
Vol 39 (1) ◽  
pp. 251-261
Author(s):  
Abderrahim Mokhefi ◽  
Mohamed Bouanini ◽  
Mohammed Elmir
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Laminar Flow ◽  
Base Fluid ◽  
Volume Fraction ◽  
Stirred Tank ◽  
Alumina Nanoparticles ◽  
Hydrodynamic Effect ◽  
Al2o3 Nanoparticles ◽  
Behavior Index

The purpose of research presented in this paper is to study the thermal and hydrodynamic effect of the non-isothermal laminar flow of a Al2O3-water nanofluid having shear thinning behavior in a mechanically stirred tank using the finite element method. Numerical simulation has been performed for a non-stationary two-dimensional flow controlled by certain influencing parameters such as the Reynolds number (1 ≤ Re ≤ 200), the behavior index (0.6 ≤ n ≤ 1) and the volume fraction of the alumina nanoparticles (0 ≤ φ ≤ 0.1). The simulation results obtained show that the addition of the Al2O3 nanoparticles in the base fluid leads to a significant enhancement in the heat transfer in the stirred tank compared to the base fluid. On the other hand, we note a slight decrease in the heat transfer with the decrease in the behavior index. It has also been noted, that the agitation power increases relatively with the volume fraction of the Alumina nanoparticles.

Flow and Heat Transfer of Nanoencapsulated Phase Change Material Slurry Past a Unconfined Square Cylinder

2014 ◽  
Vol 136 (5) ◽  
Author(s):  
Hamid Reza Seyf ◽  
Michael R. Wilson ◽  
Yuwen Zhang ◽  
H. B. Ma
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Phase Change ◽  
Melting Temperature ◽  
Base Fluid ◽  
Volume Fraction ◽  
Pure Water ◽  
Reynolds Numbers ◽  
Square Cylinder ◽  
Change Material

Numerical solution is carried out to analyze the effect of nanoencapsulated phase change material (NEPCM) slurry on forced convection heat transfer of steady laminar flow past an isothermal square cylinder. The base fluid is water while the NEPCM particles material is n-octadecane with an average diameter of 100 nm. A parametric study was performed for different volume fraction of nanoparticles ranging from 0% to 30%, two melting temperature ranges, i.e., 10 K and 20 K, and different inlet Reynolds numbers ranging from 15 to 45. The governing equations of flow and energy are solved simultaneously using a finite volume method (FVM) on collocated grid arrangement. It was found that for both NEPCM slurry and pure water, local and average heat transfer coefficients increases with increasing Reynolds number. The results of heat transfer characteristics of slurry flow over the square cylinder showed remarkable enhancement relative to that of the base fluid. The enhancement intensifies for higher particle volume concentrations and higher Reynolds numbers. However, utilizing the slurry can cause higher shear stress on the wall due to higher viscosity of mixture compared to the pure water. The melting temperature range of NEPCM particles has slight effect on heat transfer, although with increasing volume fraction and Reynolds number, lower melting range leads to higher heat transfer coefficient.

A Similarity Solution for Mixed-Convection Boundary Layer Nanofluid Flow on an Inclined Permeable Surface

2017 ◽  
Vol 9 (2) ◽  
Author(s):  
Masoud Ziaei-Rad ◽  
Abbas Kasaeipoor ◽  
Mohammad Mehdi Rashidi ◽  
Giulio Lorenzini
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Mixed Convection ◽  
Friction Factor ◽  
Base Fluid ◽  
Volume Fraction ◽  
Nanofluid Flow ◽  
Wall Suction ◽  
Surface Angle

This paper concerns with calculation of heat transfer and pressure drop in a mixed-convection nanofluid flow on a permeable inclined flat plate. Solution of governing boundary layer equations is presented for some values of injection/suction parameter (f0), surface angle (γ), Galileo number (Ga), mixed-convection parameter (λ), volume fraction (φ), and type of nanoparticles. The numerical outcomes are presented in terms of average skin friction coefficient (Cf) and Nusselt number (Nu). The results indicate that adding nanoparticles to the base fluid enhances both average friction factor and Nusselt number for a wide range of other effective parameters. We found that for a nanofluid with φ = 0.6, injection from the wall (f0 = −0.2) offers an enhancement of 30% in Cf than the base fluid, while this growth is about 35% for the same case with wall suction (f0 = 0.2). However, increasing the wall suction will linearly raise the heat transfer rate from the surface, similar for all range of nanoparticles volume fraction. The computations also showed that by changing the surface angle from horizontal state to 60 deg, the friction factor becomes 2.4 times by average for all φ's, while 25% increase yields in Nusselt number for the same case. For assisting flow, there is a favorable pressure gradient due to the buoyancy forces, which results in larger Cf and Nu than in opposing flows. We can also see that for all φ values, enhancing Ga/Re2 parameter from 0 to 0.005 makes the friction factor 4.5 times, while causes 50% increase in heat transfer coefficient. Finally, we realized that among the studied nanoparticles, the maximum influence on the friction and heat transfer belongs to copper nanoparticles.

Sign in / Sign up

Export Citation Format

Share Document