scholarly journals Irreversibility Analysis for Eyring–Powell Nanoliquid Flow Past Magnetized Riga Device with Nonlinear Thermal Radiation

Fluids ◽  
2021 ◽  
Vol 6 (11) ◽  
pp. 416
Author(s):  
Ephesus Olusoji Fatunmbi ◽  
Adeshina Taofeeq Adeosun ◽  
Sulyman Olakunle Salawu

The report contained in this article is based on entropy generation for a reactive Eyring–Powell nanoliquid transfer past a porous vertical Riga device. In the developed model, the impacts of viscous dissipation, thermophoresis alongside nonlinear heat radiation and varying heat conductivity are modelled into the heat equation. The dimensionless transport equations are analytically tackled via Homotopy analysis method while the computational values of chosen parameters are compared with the Galerkin weighted residual method. Graphical information of the various parameters that emerged from the model are obtained and deliberated effectively. The consequences of this study are that the temperature field expands with thermophoresis, Brownian motion and temperature ratio parameters as the modified Hartmann number compels a rise in the velocity profile. The entropy generation rises with an uplift in fluid material term as well as Biot and Eckert numbers whereas Bejan number lessens with Darcy and Eckert parameters.

2019 ◽  
Vol 11 (12) ◽  
pp. 168781401989445 ◽  
Author(s):  
Taza Gul ◽  
Muhammad Waqas ◽  
Waqas Noman ◽  
Zafar Zaheer ◽  
Iraj S Amiri

The water-based single- and multiple-wall carbon nanotubes nanofluid over the surface of an unsteady stretched cylinder has been studied. The thin film of the carbon-nanotube nanofluid has been focused for the heat transfer enhancement applications. The well-known thermal conductivity model for the revolving tube materials like single- and multiple-walled carbon nanotubes defined by Xue were used. The modeled problem has been solved through the optimal homotopy analysis method using the BVPh 2.0 package. The distribution of the thin layer has been regulated through the pressure term using the variable thickness of the nanoliquid. The entropy generation has mainly focused during the motion of the thin layer for the both sorts of carbon nanotubes. The important features of the entropy generation and Bejan number under the influence of the physical constraints have been compared for the both types of single-wall carbon nanotubes and multiple-wall carbon nanotubes and discussed. The well-known BVPh 2.0 package of the optimal homotopy analysis method has been used to find the outcomes.


2019 ◽  
Vol 141 (10) ◽  
Author(s):  
M. Ijaz Khan ◽  
Sumaira Qayyum ◽  
T. Hayat ◽  
M. Waqas ◽  
A. Alsaedi

Abstract This paper aims to investigate the entropy generation in slip flow due to double rotating disks. Heat equation is formulated by considering effects of viscous dissipation, Joule heating and nonlinear thermal radiation. Brownian motion and thermophoresis effects of nanofluid are also discussed. Applied magnetic field is considered to be time dependent. Homogeneous–heterogeneous reactions are also studied. Von Karman transformations are used. Homotopy analysis method is implemented on system of equations for convergent series solutions. Influence of various flow parameters on entropy, Bejan number, velocity, temperature, Nusselt number, and skin friction is discussed through graphs and tables. Axial velocity decays for higher nonlinear mixed convection variable of temperature and velocity slip parameter. Temperature rises for larger thermal slip parameter and thermophoresis parameter. Entropy and Bejan number are increasing for higher estimation of homogeneous reaction parameter and diffusion parameters.


Entropy ◽  
2020 ◽  
Vol 22 (10) ◽  
pp. 1171
Author(s):  
Umair Rashid ◽  
Dumitru Baleanu ◽  
Azhar Iqbal ◽  
Muhammd Abbas

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.


Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 262 ◽  
Author(s):  
Asad Ullah ◽  
Zahir Shah ◽  
Poom Kumam ◽  
Muhammad Ayaz ◽  
Saeed Islam ◽  
...  

The boundary-layer equations for mass and heat energy transfer with entropy generation are analyzed for the two-dimensional viscoelastic second-grade nanofluid thin film flow in the presence of a uniform magnetic field (MHD) over a vertical stretching sheet. Different factors, such as the thermophoresis effect, Brownian motion, and concentration gradients, are considered in the nanofluid model. The basic time-dependent equations of the nanofluid flow are modeled and transformed to the ordinary differential equations system by using similarity variables. Then the reduced system of equations is treated with the Homotopy Analysis Method to achieve the desire goal. The convergence of the method is prescribed by a numerical survey. The results obtained are more efficient than the available results for the boundary-layer equations, which is the beauty of the Homotopy Analysis Method, and shows the consistency, reliability, and accuracy of our obtained results. The effects of various parameters, such as Nusselt number, skin friction, and Sherwood number, on nanoliquid film flow are examined. Tables are displayed for skin friction, Sherwood number, and Nusselt number, which analyze the sheet surface in interaction with the nanofluid flow and other informative characteristics regarding this flow of the nanofluids. The behavior of the local Nusselt number and the entropy generation is examined numerically with the variations in the non-dimensional numbers. These results are shown with the help of graphs and briefly explained in the discussion. An analytical exploration is described for the unsteadiness parameter on the thin film. The larger values of the unsteadiness parameter increase the velocity profile. The nanofluid film velocity shows decline due the increasing values of the magnetic parameter. Moreover, a survey on the physical embedded parameters is given by graphs and discussed in detail.


Processes ◽  
2019 ◽  
Vol 7 (9) ◽  
pp. 626 ◽  
Author(s):  
Asad Mahmood ◽  
Md Md Basir ◽  
Umair Ali ◽  
Mohd Mohd Kasihmuddin ◽  
Mohd. Mansor

This paper studies heat transfer in a two-dimensional magnetohydrodynamic viscous incompressible flow in convergent/divergent channels. The temperature profile was obtained numerically for both cases of convergent/divergent channels. It was found that the temperature profile increases with an increase in Reynold number, Prandtl number, Nusselt number and angle of the wall but decreases with an increase in Hartmann number. A relatively new numerical method called the spectral homotopy analysis method (SHAM) was used to solve the governing non-linear differential equations. The SHAM 3rd order results matched with the DTM and shooting, showing that SHAM is feasible as a technique to be used.


2021 ◽  
pp. 2150342
Author(s):  
P.-Y. Xiong ◽  
M. Ijaz Khan ◽  
R. J. Punith Gowda ◽  
R. Naveen Kumar ◽  
B. C. Prasannakumara ◽  
...  

This investigation is about hybrid nanofluid flowing over a sheet. We considered two-dimensional Darcy–Forchheimer flow of different hybrid nanofluids with the influence of uniform heat source sink and nonlinear thermal radiation. Different nanoparticles can be used to improve the thermal conductivity of a liquid. A study comparing the various hybrid nanofluids to nanofluid is considered. Here, we have selected manganese Zinc ferrite and Nickel Zinc ferrite as nanoparticles with kerosene oil and engine oil as carrier liquids. Suitable similarity transformations are used to construct the required ordinary differential equations. The influence of several non-dimensional parameters on velocity and thermal gradients is analyzed through graphs. Also, entropy generation is computed and analyzed through graph for different involved parameters. Here, we observed that [Formula: see text]–[Formula: see text]–[Formula: see text]–[Formula: see text] had lower velocity when compared to other two solutions. The entropy generation and Bejan number are high in [Formula: see text]–[Formula: see text]–[Formula: see text] when compared to [Formula: see text]–[Formula: see text]–[Formula: see text]–[Formula: see text] and [Formula: see text]–[Formula: see text]–[Formula: see text] and increase in heat generation parameter increases the rate of heat transfer.


Author(s):  
Y. M. Aiyesimi ◽  
M. Jiya ◽  
G. A. Bolarin ◽  
O. V. Akinremi

The combined effects of chemical reaction, radially applied magnetic field and Hall effect on entropy generation of a steady third grade magnetohydrodynamic fluid flowing through a uniformly circular pipe was studied. The governing equations are presented and the resulting non-linear dimensionless equations are solved numerically using Galerkin Weighted Residual Method. The velocity, temperature and concentration profile were obtained and utilized in computing the entropy number. A parametric study of germane parameters involved are presented graphically and discussed. It was observed that irreversibility due to heat transfer dominates the flow compared to fluid friction and Hall parameter inhibits the Bejan number while Magnetic parameter enhances the Bejan number.


2020 ◽  
pp. 183-183
Author(s):  
Najma Saleem

This study reveals the entropy analysis of hydromagnetic pumping flow of Williamson fluid through a two-dimensional symmetric channel carrying cilia. Propulsive metachronal waves are mobilized by whipping and beating of uniformly distributed cilia which follow elliptic trajectory movements in the parallel direction of flow. The flow is resisted by a uniform transverse magnetic field. The entire study is carried out in wave frame of reference. After implying lubrication approximations, the governing equations of the present flow problem are solved by perturbation method. Effects of physical parameters of interest on various flow quantities, the total entropy generation number and the Bejan number are plotted and discussed. It is observed that fluid velocity and temperature is enhanced in the core channel region for small values of Hartmann number and cilia length. It is also noticed that the entropy generation and the Bejan number are decreasing function of magnetic field. Near the channel center, irreversibility due to fluid friction is dominant but at the channel wall heat transfer irreversibility effects are observed to be substantial. The confined bolus reduces in size for small values of cilia length parameter and large values of Hartmann number.


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