Physical importance of entropy generation in fluid flow (Williamson) with nonlinear radiative heat flux

Author(s):  
Niaz B. Khan ◽  
M. Imran Khan ◽  
Waqar Azeem Khan ◽  
M. K. Nayak
2018 ◽  
Vol 260 ◽  
pp. 279-291 ◽  
Author(s):  
Muhammad Ijaz Khan ◽  
Siraj Ullah ◽  
Tasawar Hayat ◽  
Muhammad Imran Khan ◽  
Ahmed Alsaedi

2018 ◽  
Vol 96 (1) ◽  
pp. 1-10 ◽  
Author(s):  
M. Bilal ◽  
M. Sagheer ◽  
S. Hussain

In this study, three-dimensional upper-convected Maxwell fluid flow over a stretching surface in the presence of viscous dissipation and Joule heating is considered to examine the effects of thermophoresis and magnetohydrodynamics (MHD) on heat and mass transfer. Energy equation is formulated under the assumption of nonlinear radiative heat flux. Ordinary differential equations are deduced from the governing partial differential equations with the help of similarity transformation. These equations are then solved numerically using the shooting method, through the fourth-order Runge–Kutta integration procedure. To strengthen the reliability of our results, the MATLAB built-in function bvp4c is also used. Effects of some prominent physical parameters, such as Eckert number, Prandtl number, thermophoretic parameter, and magnetic parameter on the velocity, temperature, and concentration profiles are discussed graphically and numerically. It is found that concentration profile decreases for the higher values of thermophoretic parameter and Schmidt number. The heat flux rate is observed to enhance for increasing values of thermal radiation and Prandtl number.


2020 ◽  
Vol 16 (6) ◽  
pp. 1475-1496
Author(s):  
A. Roja ◽  
B.J. Gireesha ◽  
B.C. Prasannakumara

PurposeMiniaturization with high thermal performance and lower cost is one of the advanced developments in industrial science chemical and engineering fields including microheat exchangers, micro mixers, micropumps, cooling microelectro mechanical devices, etc. In addition to this, the minimization of the entropy is the utilization of the energy of thermal devices. Based on this, in the present investigation, micropolar nanofluid flow through an inclined channel under the impacts of viscous dissipation and mixed convection with velocity slip and temperature jump has been numerically studied. Also the influence of magnetism and radiative heat flux is used.Design/methodology/approachThe nonlinear system of ordinary differential equations are obtained by applying suitable dimensionless variables to the governing equations, and then the Runge–Kutta–Felhberg integration scheme is used to find the solution of velocity and temperature. Entropy generation and Bejan number are calculated via using these solutions.FindingsIt is established to notice that the entropy generation can be improved with the aspects of viscous dissipation, magnetism and radiative heat flux. The roles of angle of inclination (α), Eckert number (Ec), Reynolds number (Re), thermal radiation (Rd), material parameter (K),  slip parameter (δ), microinertial parameter (aj), magnetic parameter (M), Grashof number (Gr) and pressure gradient parameter (A) are demonstrated. It is found that the angle of inclination and Grashof number enhances the entropy production while it is diminished with material parameter and magnetic parameter.Originality/valueElectrically conducting micropolar nanofluid flow through an inclined channel subjected to the friction irreversibility with temperature jump and velocity slip under the influence of radiative heat flux has been numerically investigated.


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