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PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260854
Author(s):  
Muhammad Ramzan ◽  
Abdullah Dawar ◽  
Anwar Saeed ◽  
Poom Kumam ◽  
Wiboonsak Watthayu ◽  
...  

The present study is related to the analytical investigation of the magnetohydrodynamic flow of Ag − MgO/ water hybrid nanoliquid with slip conditions via an extending surface. The thermal radiation and Joule heating effects are incorporated within the existing hybrid nanofluid model. The system of higher-order partial differential equations is converted to the nonlinear system of ordinary differential equations by interpreting the similarity transformations. With the implementation of a strong analytical method called HAM, the solution of resulting higher-order ordinary differential equations is obtained. The results of the skin friction coefficient, Nusselt number, velocity profile, and temperature profile of the hybrid nanofluid for varying different flow parameters are attained in the form of graphs and tables. Some important outcomes showed that the Nusselt number and skin friction are increased with the enhancement in Eckert number, stretching parameter, heat generation parameter and radiation parameter for both slip and no-slip conditions. The thermal profile of the hybrid nanofluid is higher for suction effect but lower for Eckert number, stretching parameter, magnetic field, heat generation and radiation parameter. For both slip and no-slip conditions, the hybrid nanofluid velocity shows an upward trend for both the stretching and mixed convection parameters.


Author(s):  
J.C. Umavathi ◽  
O. Anwar Bég

Motivated by developments in thermal duct processing, an investigation is presented to study the behavior of viscous nanoparticle suspensions flowing in a vertical duct subject to Fourier-type conditions. The left wall temperature is kept lower than that of the right wall. Brownian motion and thermophoresis which are invoked via the presence of nanoparticles are incorporated in the study. Numerical solutions with an efficient Runge–Kutta shooting method are also presented at all values of the control parameters. The impact of thermal Grashof number [Formula: see text], Eckert number [Formula: see text], thermophoresis [Formula: see text], and Brownian motion parameters [Formula: see text] on the velocity, temperature, and nanoparticle concentration distributions for identical [Formula: see text] and differing Biot numbers [Formula: see text] (at the duct walls) are computed and visualized graphically. With vanishing thermophoresis and Brownian motion parameters, the solutions match exactly with the earlier Newtonian viscous flow computations. Symmetric and asymmetric wall heat conditions are also acknowledged. Intensifying the thermal Grashof number, Eckert number, thermophoresis parameter, and Brownian parameter serve to amplify magnitudes of the velocity and temperature, whereas the nanoparticle concentration field is suppressed. The skin friction and Sherwood number are also computed with various combinations of the flow control parameters. Nusselt number values at the hot duct wall are enhanced with an increase in thermal buoyancy parameter, Eckert number, Brownian motion parameter, and thermophoresis parameter for equal Biot numbers. The opposite trend is computed for different Biot numbers. For any given values of Biot numbers, the mean velocity and bulk temperature are boosted with increase in thermal buoyancy parameter, Eckert number, Brownian motion parameter, and thermophoresis parameter. Hence, it may be inferred that the transport characteristics computed using Fourier-type boundary conditions are substantially different from those based on isothermal boundary conditions in nanofluid duct flows.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Umar Nazir ◽  
Muhammad Sohail ◽  
Mahmoud M. Selim ◽  
Hussam Alrabaiah ◽  
Poom Kumam

AbstractInvolvement of hybrid nanoparticles a vital role to improve the efficiency of thermal systems. This report covers the utilization of different nanoparticles mixed in Carreau Yasuda material for the improvement of thermal performance. The configuration of flow situation is considered over a rotating porous cone by considering the Hall and Ion slip forces. Transport of momentum is considered to be in a rotating cone under generalized ohm’s law and heat transfer is presented by considering viscous dissipation, Joule heating and heat generation. Rheology of considered model is derived by engaging the theory proposed by Prandtl. Modeled complex PDEs are reduced into ODEs under similarity transformation. To study the physics behind this phenomenon, solution is essential. Here, FEM (Finite Element Method) is adopted to compute the solution. Furthermore, the grid independent study is reported with several graphs and tables which are prepared to note the influence of involved parameters on thermal and velocity fields. It is worth mentioning that heat transport is controlled via higher radiation parameter and it upsurges for Eckert number. Moreover, Hall and ion slip parameters are considered significant parameters to produce the enhancement in motion of fluid particles but speed of nano and hybrid nanoparticles becomes slow down versus large values of Forchheimer and Weissenberg numbers. Additionally, an enhancement in production of heat energy is addressed via large values of heat generation number and Eckert number while reduction in heat energy is occurred due to positive values of thermal radiation and Hall and ion slip parameters.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Ramzan ◽  
Noor Saeed Khan ◽  
Poom Kumam

AbstractThe study concerns with the mechanical characteristics of heat and mass transfer flow of a second grade nanofluid as well as gyrotatic microorganism motion past a thin needle with dipole effect, entropy generation, thermal radiation, Arrhenius activation energy and binar chemical reaction. The governing equations and boundary conditions are simplified by the use of suitable similarity transformations. Homotopy analysis method is implemented to obtain the series solution of non-linear ordinary differential equations. Physical behaviors of heat and mass transfer flow with gyrotatic microorganisms and entropy generation are investigated through the embedded parameters. The nanofluid velocity is enhanced for higher values of the ferromagnetic parameter, local Grashof number, bioconvection Rayleigh number and radiation parameter. The Reynolds number, radiation parameter and Eckert number decrease the nanofluid temperature. The entropy generation is increased with the enhancement of radiation parameter, Eckert number, Lewis number, temperature difference parameter, dimensionless constant parameter, Curie temperature, Prandtl number and concentration difference parameter.


Author(s):  
M Riaz Khan ◽  
C Ahamed Saleel ◽  
Tareq Saeed ◽  
FM Allehiany ◽  
Adel M El-Refaey ◽  
...  

The ongoing work investigates the features of Joule heating and convective condition over a magnetohydrodynamic stagnation point flow of [Formula: see text] nanofluid moving across a curved surface. Moreover, mass suction is supposed through the stretching/shrinking surface. The initially developed model of partial differential equations is transformed into the ordinary ones assisted by suitable similarity variables. Subsequently, the ultimate nonlinear model of ordinary differential equations is solved with the help of a built-in function bvp4c package in MATLAB. Several graphical results are plotted to see the influence of various dimensionless parameters over the velocity, temperature, heat transfer, and friction drag. We found that there exists an escalation in temperature with increasing values of curvature, Eckert number, Hartmann number, and Biot number; however, the velocity profile declines with large curvature, ratio parameter, and high concentration of nanoparticles. It is also important to note that the friction drag rises with the mass suction, and reduces with vast curvature, whereas the rate of heat transfer improves with suction and Biot number but lowers with Eckert number and Hartmann number.


2021 ◽  
Vol 39 (4) ◽  
pp. 1180-1196
Author(s):  
Rajesh Kumar Chandrawat ◽  
Varun Joshi

In this paper, the unsteady magnetohydrodynamic (MHD) Couette flow of two non-Newtonian immiscible fluids micropolar and micropolar dusty (fluid-particle suspension) are considered in the horizontal channel with heat transfer. A comprehensive mathematical model and computational simulation with the modified cubic B-Spline-Differential Quadrature method (MCB-DQM) is described for unsteady flow. The coupled partial differential equation for fluid and particle-phase are formulated and the effect of viscous dissipation, Joule heating, Hall current, and other hydrodynamic and solutal parameters i. e. Reynolds number, Eckert number, particle concentration parameter, Eringen micropolar material parameter, time, viscosity ratio, and density ratio on the flow rate, micro rotation, and temperature characteristics were investigated. The analysis of obtained results reveals that the fluids and particle velocities are slightly decreasing with Hartmann number, and increasing with time, ion-slip, and Hall parameters. Microrotation declined with Microrotations dropped significantly with ion-slip and Hall parameter and grown Hartman number. The temperature begins to rise as time, Hartman number, and Eckert number grow and declined with Ion-slip and Hall parameter.


Entropy ◽  
2021 ◽  
Vol 23 (8) ◽  
pp. 1069
Author(s):  
N. Ameer Ahammad ◽  
Irfan Anjum Badruddin ◽  
Sarfaraz Kamangar ◽  
H.M.T. Khaleed ◽  
C. Ahamed Saleel ◽  
...  

This article presents an investigation of heat transfer in a porous medium adjacent to a vertical plate. The porous medium is subjected to a magnetohydrodynamic effect and suction velocity. The governing equations are nondepersonalized and converted into ordinary differential equations. The resulting equations are solved with the help of the finite difference method. The impact of various parameters, such as the Prandtl number, Grashof number, permeability parameter, radiation parameter, Eckert number, viscous dissipation parameter, and magnetic parameter, on fluid flow characteristics inside the porous medium is discussed. Entropy generation in the medium is analyzed with respect to various parameters, including the Brinkman number and Reynolds number. It is noted that the velocity profile decreases in magnitude with respect to the Prandtl number, but increases with the radiation parameter. The Eckert number has a marginal effect on the velocity profile. An increased radiation effect leads to a reduced thermal gradient at the hot surface.


2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Solomon Bati Kejela ◽  
Mitiku Daba ◽  
Abebe Girum

Analytical investigation of thermal radiation, Prandtl number, Eckert number, permeability parameter, magnetic field, velocity, and thermal slip effects on magnetohydrodynamic Hiemenz flow over a permeable plate with forced convection has been presented. Similarity variable conversion method has been applied to transmute the fundamental governing equations of the fluid dynamics in flow into a pair of nonlinear third-order ordinary differential equations and is analytically solved by the optimal homotopy asymptotic method (OHAM). The influences of several relevant physical parameters in the model on velocity and temperature of the fluid have been studied and analysed profoundly by use of graphs and tables. It is detected that, with mounting value of suction/blowing parameter and magnetic field parameter, the skin friction coefficient enhances. Likewise, it is seen that the Nusselt number increases with enhancing value of magnetic parameter. It is also witnessed that the velocity increases as the Eckert number, blowing/suction parameter, and permeability parameter increase, but it decays against magnetic field and velocity slip parameter. Moreover, the result reveals that the fluid temperature upsurges along with snowballing the radiant heat, magnetic field parameter, and the Eckert number. However, it descends against thermal slip parameter, Prandtl number, wall temperature exponent, and velocity slip parameter. A comparison with previous studies has been made, and the result shows an excellent agreement.


2021 ◽  
Vol 10 (1) ◽  
pp. 31-44
Author(s):  
Bullo Hindebu Rikitu ◽  
Oluwole Daniel Makinde ◽  
Lemi Guta Enyadene

Heat transfer characteristics and hydrodynamical properties of ferrofluid through microchannels with non-uniform permeable walls temperature and filled with porous media plays an important role in modern microfluidic applications, such as solar collectors, nuclear reactors, micro-electro-chemical cell transport, micro heat exchanging, microchip cooling, and electronic equipment. Therefore, this paper presents the investigation of ferrofluid (Fe3O4-H2O) heat transfer characteristics as well as hydrodynamical properties in a permeable microchannel with non-uniform permeable walls. The semi-discretization finite difference method is utilized to solve the highly non-linear partial differential equations that govern the momentum and energy equations. Accordingly, the numerical outcomes reveal that the ferrofluid velocity and temperature profiles indicate a rising trend as the pressure gradient parameter, the variable viscosity parameter, the Darcy number, the Eckert number, and Prandtl number increase. The Reynolds number, which is a suction/injection parameter, shows a contrary influence on the ferrofluid velocity and temperature whereas nanoparticles volume fraction and the Forchheimer constant show a decreasing effect on the ferrofluid velocity and temperature. The outcomes also depict that the coefficient of skin friction at the cold wall of the microchannel is larger for higher values of the nanoparticles volume fraction, the variable viscosity parameter, the Darcy number, and the Eckert number. Besides, the coefficient of skin friction at the hot wall rises with the Darcy number, and the Prandtl number. Furthermore, the heat transfer rate at both cold and hot walls of the microchannel increases as the variable viscosity parameter, the Darcy number, the Eckert number, and the Prandtl number increase. The nanoparticles volume fraction and Darcy number show a retarding effect on the heat transfer rate at both walls of the microchannel.


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