Heat Transfer Enhancement of Water Based Al2O3- Cu Hybrid Nanofluid Trough Square Cavity

2021 ◽  
Vol 1167 ◽  
pp. 87-100
Author(s):  
Amira Trodi ◽  
Mohamed El Hocine Benhamza
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Volume Fraction ◽  
General Structure ◽  
Hybrid Nanofluid ◽  
Transfer Enhancement ◽  
Numerical Work ◽  
Thermal Fields ◽  
Nanoparticles Volume Fraction ◽  
Volume Method

The present numerical work, based on the finite volume method, deals with the characterization of natural convective flow and thermal fields inside differentially vertical heated square cavities filled with a nanofluid as well as the quantification of the convective exchanges. The investigation is devoted to study the influence of the hybrid nanofluid (Al2O3-Cu / water) on the flow’s general structure with a particular attention to the Nusselt number. An exhaustive parametric study is conducted considering different combinations of Al2O3 and Cu nanoparticles (NPs) dispersed in water for a range of Rayleigh numbers (Ra) and total volume fractions An appropriate agreement with experimental data was observed for the estimation of the hybrid nanofluid thermal conductivity. From the results, it is observed that the heat transfer intensifies by increasing the Ra number and the nanoparticles volume fraction. The hybrid nanofluid seems to be the most efficient nanofluid in comparison with a base fluid and a single nanofluid. This heat transfer enhancement becomes more convincing with the increase of the Cu NPs content (% in volume).

Numerical Analysis of Unsteady Conjugate Natural Convection of Hybrid Water-Based Nanofluid in a Semicircular Cavity

2017 ◽  
Vol 9 (4) ◽  
Author(s):  
Ali J. Chamkha ◽  
Igor V. Miroshnichenko ◽  
Mikhail A. Sheremet
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Transfer Enhancement ◽  
Volume Fraction ◽  
Finite Thickness ◽  
Hybrid Nanofluid ◽  
Dimensionless Time ◽  
Transfer Enhancement ◽  
Conjugate Natural Convection ◽  
Water Based

Unsteady conjugate natural convection in a semicircular cavity with a solid shell of finite thickness filled with a hybrid water-based suspension of Al2O3 and Cu nanoparticles (hybrid nanofluid) has been analyzed numerically. The governing equations for this investigation are formulated in terms of the dimensionless stream function, vorticity, and temperature and have been solved by the finite difference method of the second-order accuracy. The effects of the dimensionless time, Rayleigh number, thermal conductivity ratio, and the nanoparticles volume fraction on the flow patterns and heat transfer have been studied. The obtained results have revealed essential heat transfer enhancement at solid–fluid interface with addition of nanoparticles. In addition, a comparison of the heat transfer enhancement level due to the suspension of various nanoparticles materials (Al2O3 and Cu) in water as regular nanofluids (Al2O3/water and Cu/water) and as a hybrid Al2O3–Cu/water nanofluid is reported.

Numerical Investigations of Heat Transfer Enhancement of Water-Based Al2O3 Nanofluids in a Sinusoidal-Wall Channel

2013 ◽  
Author(s):  
Veli Ozbolat ◽  
Besir Sahin
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Volume Fraction ◽  
Wave Length ◽  
Nano Particles ◽  
Transfer Enhancement ◽  
Fully Developed Flow ◽  
Nusselt Numbers ◽  
Energy Equations ◽  
Volume Method

This research numerically investigates the heat transfer of water-Al2O3 nanofluids in a two dimensional sinusoidal wavy channel. Simulation studies are performed for fully developed flow conditions in a channel with eight waves. The temperature of the input fluid is taken to be less than that temperature of wavy walls. The governing continuity, momentum and energy equations are numerically solved using finite volume method based on SIMPLE technique. Numerical simulations were carried out for a Reynolds number ranging from 400 to 1600 and a nanofluid volume fraction, Ø where 0≤Ø≤8%. The effect of distance between channel walls are studied by varying Hmin/Hmax ratio from 0.3 to 0.5 for keeping wave length and wave amplitude values fixed. The effect of these parameters on local and average Nusselt numbers and heat transfer enhancement are presented and discussed. The results revealed that the addition of nano-particles can increase heat transfer significantly.

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 Heat Transfer Enhancement of TiO2/Water Nanofluids Flowing Inside a Square Minichannel with a Microfin Structure: A Numerical Investigation

Energies ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 3041 ◽  
Author(s):  
Budi Kristiawan ◽  
Agung Tri Wijayanta ◽  
Koji Enoki ◽  
Takahiko Miyazaki ◽  
Muhammad Aziz
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Volume Fraction ◽  
Practical Application ◽  
Transfer Enhancement ◽  
Working Fluids ◽  
Performance Evaluation Criterion ◽  
Developing Flow ◽  
And Performance ◽  
Economic Considerations

A combination of two passive heat transfer enhancement techniques using a microfin structure and nanofluids was investigated numerically. TiO2/water nanofluids flowing inside a square minichannel with a microfin structure (SMM) were observed as a practical application. Increased heat transfer performance was investigated by observing the Nusselt number, friction factor, and performance evaluation criterion (PEC). Velocity and temperature profiles were also demonstrated at a laminar developing flow regime. The SMM used in this work had six microfins (N = 6) and TiO2/water nanofluids with various nanoparticle concentrations of 0.005, 0.01, and 0.1 vol.%. By combining nanofluids as working fluids and SMM as a passive heat transfer enhancement, the maximum PEC value of 1.2 was achieved at Re = 380 with a volume fraction of 0.01 vol.%. It is obvious that compared to water flowing inside the square minichannel microfin, the heat transfer can be increased by using only a nanofluid with a volume fraction of 0.01%. The combination of a microfin and nanofluids as working fluids is strongly recommended due to its excellent performance in terms of heat transfer and economic considerations.

scholarly journals Investigation of the novelty of latent functionally thermal fluids as alternative to nanofluids in natural convective flows

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zoubida Haddad ◽  
Farida Iachachene ◽  
Eiyad Abu-Nada ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Enhancement ◽  
Volume Fraction ◽  
Heat Of Fusion ◽  
Transfer Enhancement ◽  
Maximum Heat ◽  
Thermal Fluids ◽  
Maximum Heat Transfer ◽  
Wide Range

AbstractThis paper presents a detailed comparison between the latent functionally thermal fluids (LFTFs) and nanofluids in terms of heat transfer enhancement. The problem used to carry the comparison is natural convection in a differentially heated cavity where LFTFs and nanofluids are considered the working fluids. The nanofluid mixture consists of Al2O3 nanoparticles and water, whereas the LFTF mixture consists of a suspension of nanoencapsulated phase change material (NEPCMs) in water. The thermophysical properties of the LFTFs are derived from available experimental data in literature. The NEPCMs consist of n-nonadecane as PCM and poly(styrene-co-methacrylic acid) as shell material for the encapsulation. Finite volume method is used to solve the governing equations of the LFTFs and the nanofluid. The computations covered a wide range of Rayleigh number, 104 ≤ Ra ≤ 107, and nanoparticle volume fraction ranging between 0 and 1.69%. It was found that the LFTFs give substantial heat transfer enhancement compared to nanofluids, where the maximum heat transfer enhancement of 13% was observed over nanofluids. Though the thermal conductivity of LFTFs was 15 times smaller than that of the base fluid, a significant enhancement in thermal conductivity was observed. This enhancement was attributed to the high latent heat of fusion of the LFTFs which increased the energy transport within the cavity and accordingly the thermal conductivity of the LFTFs.

Numerical Study of Heat Transfer Enhancement Using Al2O3–Graphene/Water Hybrid Nanofluid Flow in Mini Tubes

2019 ◽  
Vol 43 (4) ◽  
pp. 1989-2000 ◽  
Author(s):  
Ahmed A. Hussien ◽  
Nadiahnor Md Yusop ◽  
Moh’d A. Al-Nimr ◽  
Mohd Z. Abdullah ◽  
Ayub Ahmed Janvekar ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Transfer Enhancement ◽  
Numerical Study ◽  
Hybrid Nanofluid ◽  
Transfer Enhancement ◽  
Nanofluid Flow
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