Exploring the heat transfer and entropy generation of Ag/Fe$$_3$$O$$_4$$-blood nanofluid flow in a porous tube: a collocation solution

2021 ◽  
Vol 44 (3) ◽  
Author(s):  
H. Thameem Basha ◽  
R. Sivaraj
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Nanofluid Flow ◽  
Porous Tube ◽  
Collocation Solution

scholarly journals Non-Newtonian effect on heat transfer and entropy generation of natural convection nanofluid flow inside a vertical wavy porous cavity

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Mahbuba Tasmin ◽  
Preetom Nag ◽  
Zarin T. Hoque ◽  
Md. Mamun Molla
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Entropy Generation ◽  
Power Law ◽  
Volume Fraction ◽  
Local Entropy ◽  
Nanofluid Flow ◽  
Porosity Level ◽  
Power Law Index ◽  
Local Entropy Generation

AbstractA numerical study on heat transfer and entropy generation in natural convection of non-Newtonian nanofluid flow has been explored within a differentially heated two-dimensional wavy porous cavity. In the present study, copper (Cu)–water nanofluid is considered for the investigation where the specific behavior of Cu nanoparticles in water is considered to behave as non-Newtonian based on previously established experimental results. The power-law model and the Brinkman-extended Darcy model has been used to characterize the non-Newtonian porous medium. The governing equations of the flow are solved using the finite volume method with the collocated grid arrangement. Numerical results are presented through streamlines, isotherms, local Nusselt number and entropy generation rate to study the effects of a range of Darcy number (Da), volume fractions (ϕ) of nanofluids, Rayleigh numbers (Ra), and the power-law index (n). Results show that the rate of heat transfer from the wavy wall to the medium becomes enhanced by decreasing the power-law index but increasing the volume fraction of nanoparticles. Increase of porosity level and buoyancy forces of the medium augments flow strength and results in a thinner boundary layer within the cavity. At negligible porosity level of the enclosure, effect of volume fraction of nanoparticles over thermal conductivity of the nanofluids is imperceptible. Interestingly, when the Darcy–Rayleigh number $$Ra^*\gg 10$$ R a ∗ ≫ 10 , the power-law effect becomes more significant than the volume fraction effect in the augmentation of the convective heat transfer process. The local entropy generation is highly dominated by heat transfer irreversibility within the porous enclosure for all conditions of the flow medium. The particular wavy shape of the cavity strongly influences the heat transfer flow pattern and local entropy generation. Interestingly, contour graphs of local entropy generation and local Bejan number show a rotationally symmetric pattern of order two about the center of the wavy cavity.

Thermodynamic optimization of nanofluid flow over a non-isothermal wedge with nonlinear radiation and activation energy

2021 ◽  
Author(s):  
M R Acharya ◽  
P Mishra ◽  
Satyananda Panda
Keyword(s):  
Heat Transfer ◽  
Activation Energy ◽  
Reynolds Number ◽  
Entropy Generation ◽  
Volume Fraction ◽  
Mathematical Formulation ◽  
Bejan Number ◽  
Nanofluid Flow ◽  
Entropy Generation Number ◽  
Generation Number

Abstract This paper analyses the augmentation entropy generation number for a viscous nanofluid flow over a non-isothermal wedge including the effects of non-linear radiation and activation energy. We discuss the influence of thermodynamically important parameters during the study, namely, the Bejan number, entropy generation number, and the augmentation entropy generation number. The mathematical formulation for thermal conductivity and viscosity of nanofluid for Al2O3 − EG mixture has been considered. The results were numerically computed using implicit Keller-Box method and depicted graphically. The important result is the change in augmentation entropy generation number with Reynolds number. We observed that adding nanoparticles (volume fraction) tend to enhance augmentation entropy generation number for Al2O3 − EG nanofluid. Further, the investigation on the thermodynamic performance of non-isothermal nanofluid flow over a wedge reveals that adding nanoparticles to the base fluid is effective only when the contribution of heat transfer irreversibility is more than fluid friction irreversibility. This work also discusses the physical interpretation of heat transfer irreversibility and pressure drop irreversibility. This dependency includes Reynolds number and volume fraction parameter. Other than these, the research looked at a variety of physical characteristics associated with the flow of fluid, heat and mass transfer.

Nanofluid flow and heat transfer due to natural convection in a semi-circle/ellipse annulus using modified lattice Boltzmann method

2019 ◽  
Vol 29 (12) ◽  
pp. 4746-4763 ◽  
Author(s):  
Qingang Xiong ◽  
Arash Khosravi ◽  
Narjes Nabipour ◽  
Mohammad Hossein Doranehgard ◽  
Aida Sabaghmoghadam ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Lattice Boltzmann Method ◽  
Entropy Generation ◽  
Lattice Boltzmann ◽  
Temperature Fields ◽  
Shape Effect ◽  
Nanofluid Flow ◽  
Content Type ◽  
Boltzmann Method

Purpose This paper aims to numerically investigate the nanofluid flow, heat transfer and entropy generation during natural convection in an annulus. Design/methodology/approach The lattice Boltzmann method is used to simulate the velocity and temperature fields. Furthermore, some special modifications are applied to make the lattice Boltzmann method capable for simulation in the curved boundary conditions. The annulus is filled with CuO-water nanofluid. The dynamic viscosity of nanofluid is estimated using KLL (Koo-Kleinstreuer-Li) model, and the nanoparticle shape effect is taken account in calculating the thermal conductivity. On the other hand, the local/volumetric entropy generation is used to show the irreversibility under influence of different parameters. Findings The effect of considered governing parameters including Rayleigh number (103<Ra < 106); nanoparticle concentration (0<<0.04) and configuration of annulus on the flow structure; temperature field; and local and total entropy generation and heat transfer rate are presented. Originality/value The originality of this work is using of lattice Boltzmann method is simulation of natural convection in a curved configuration and using of Koo–Kleinstreuer–Li correlation for simulation of nanofluid.

scholarly journals Influence of heat generation/absorption and stagnation point on polystyrene–TiO2/H2O hybrid nanofluid flow

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sadaf Masood ◽  
Muhammad Farooq ◽  
Aisha Anjum
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Stagnation Point ◽  
Entropy Generation ◽  
Heat Generation ◽  
Velocity Ratio ◽  
Hybrid Nanofluid ◽  
Engineering System ◽  
Nanofluid Flow ◽  
Homotopy Analysis

AbstractThis article focuses on hybrid nanofluid flow induced by stretched surface. The present context covers stagnation point flow of a hybrid nanofluid with the effect of heat generation/absorption. Currently most famous class of nanofluids is Hybrid nanofluid. It contains polystyrene and titanium oxide as a nanoparticles and water as a base fluid. First time attributes of heat transfer are evaluated by utilizing polystyrene–TiO2/H2O hybrid nanofluid with heat generation/absorption. Partial differential equations are converted into ordinary differential equation by using appropriate transformations for heat and velocity. Homotopy analysis method is operated for solution of ordinary differential equations. Flow and heat are disclosed graphically for unlike parameters. Resistive force and heat transfer rate is deliberated mathematically and graphically. It is deduced that velocity field enhanced for velocity ratio parameter whereas temperature field grows for heat generation/absorption coefficient. To judge the production of any engineering system entropy generation is also calculated. It is noticed that entropy generation grows for Prandtl number and Eckert number while it shows opposite behavior for temperature difference parameter.

scholarly journals Shape Effect of Nanosize Particles on Magnetohydrodynamic Nanofluid Flow and Heat Transfer over a Stretching Sheet with Entropy Generation

Entropy ◽  
2020 ◽  
Vol 22 (10) ◽  
pp. 1171
Author(s):  
Umair Rashid ◽  
Dumitru Baleanu ◽  
Azhar Iqbal ◽  
Muhammd Abbas
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Stretching Sheet ◽  
Graphical Form ◽  
Physical Parameters ◽  
Shape Effect ◽  
Analysis Method ◽  
Nanofluid Flow ◽  
Flow And Heat Transfer ◽  
Homotopy Analysis

Magnetohydrodynamic nanofluid technologies are emerging in several areas including pharmacology, medicine and lubrication (smart tribology). The present study discusses the heat transfer and entropy generation of magnetohydrodynamic (MHD) Ag-water nanofluid flow over a stretching sheet with the effect of nanoparticles shape. Three different geometries of nanoparticles—sphere, blade and lamina—are considered. The problem is modeled in the form of momentum, energy and entropy equations. The homotopy analysis method (HAM) is used to find the analytical solution of momentum, energy and entropy equations. The variations of velocity profile, temperature profile, Nusselt number and entropy generation with the influences of physical parameters are discussed in graphical form. The results show that the performance of lamina-shaped nanoparticles is better in temperature distribution, heat transfer and enhancement of the entropy generation.

Modeling heat transfer of nanofluid flow in microchannels with electrokinetic and slippery effects using Buongiorno’s model

2019 ◽  
Vol 29 (8) ◽  
pp. 2566-2587 ◽  
Author(s):  
Hang Xu ◽  
Huang Huang ◽  
Xiao-Hang Xu ◽  
Qiang Sun
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Slip Length ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Lower Wall ◽  
Volumetric Concentration ◽  
Nanofluid Flow ◽  
Cross Sectional ◽  
Content Type

PurposeThis paper aims to study the heat transfer of nanofluid flow driven by the move of channel walls in a microchannel under the effects of the electrical double layer and slippery properties of channel walls. The distributions of velocity, temperature and nanoparticle volumetric concentration are analyzed under different slip-length. Also, the variation rates of flow velocity, temperature, concentration of nanoparticle, the pressure constant, the local volumetric entropy generation rate and the total cross-sectional entropy generation are analyzed.Design/methodology/approachA recently developed model is chosen which is robust and reasonable from the point of view of physics, as it does not impose nonphysical boundary conditions, for instance, the zero electrical potential in the middle plane of the channel or the artificial pressure constant. The governing equations of flow motion, energy, electrical double layer and stream potential are derived with slip boundary condition presented. The model is non-dimensionalized and solved by using the homotopy analysis method.FindingsSlip-length has significant influences on the velocity, temperature and nanoparticle volumetric concentration of the nanofluid. It also has strong effects on the pressure constant. With the increase of the slip-length, the pressure constant of the nanofluid in the horizontal microchannel decreases. Both the local volumetric entropy generation rate and total cross-sectional entropy generation rate are significantly affected by both the slip-length of the lower wall and the thermal diffusion. The local volumetric entropy generation rate at the upper wall is always higher than that around the lower wall. Also, the larger the slip-length is, the lower the total cross-sectional entropy generation rate is when the thermal diffusion is moderate.Originality/valueThe findings in this work on the heat transfer and flow phenomena of the nanofluid in microchannel are expected to make a contribution to guide the design of micro-electro-mechanical systems.

MHD effects on heat transfer and entropy generation of nanofluid flow in an open cavity

2015 ◽  
Vol 374 ◽  
pp. 214-224 ◽  
Author(s):  
Zouhaier Mehrez ◽  
Afif El Cafsi ◽  
Ali Belghith ◽  
Patrick Le Quéré
Keyword(s):  
Heat Transfer ◽  
Entropy Generation ◽  
Open Cavity ◽  
Nanofluid Flow
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