Nonlinear radiative heat flux and heat source/sink on entropy generation minimization rate

2018 ◽  
Vol 538 ◽  
pp. 95-103 ◽  
Author(s):  
T. Hayat ◽  
M. Waleed Ahmed Khan ◽  
M. Ijaz Khan ◽  
A. Alsaedi
Keyword(s):  
Heat Flux ◽  
Heat Source ◽  
Entropy Generation ◽  
Radiative Heat ◽  
Radiative Heat Flux ◽  
Entropy Generation Minimization ◽  
Nonlinear Radiative Heat Flux ◽  
Source Sink

Entropy generation minimization (EGM) for convection nanomaterial flow with nonlinear radiative heat flux

2018 ◽  
Vol 260 ◽  
pp. 279-291 ◽  
Author(s):  
Muhammad Ijaz Khan ◽  
Siraj Ullah ◽  
Tasawar Hayat ◽  
Muhammad Imran Khan ◽  
Ahmed Alsaedi
Keyword(s):  
Heat Flux ◽  
Entropy Generation ◽  
Radiative Heat ◽  
Radiative Heat Flux ◽  
Entropy Generation Minimization ◽  
Nonlinear Radiative Heat Flux

Second law analysis on Hall effect of natural convection flow through vertical channel in the presence of uniform heat source/sink

2020 ◽  
Vol 30 (10) ◽  
pp. 4403-4423
Author(s):  
A. Roja ◽  
B.J. Gireesha
Keyword(s):  
Heat Flux ◽  
Heat Source ◽  
Viscous Dissipation ◽  
Joule Heating ◽  
Radiative Heat ◽  
Vertical Channel ◽  
Radiative Heat Flux ◽  
Content Type ◽  
Uniform Heat ◽  
Source Sink

Purpose Microfluidics is one of the extensive elaborated technologies in thermal and engineering fields due to its wide range of applications, such as micro heat exchangers, micro mixture and microchannel heat sinks, which is used to develop a large number of microscopic devices and systems. Enhancement of thermal energy using verity of nanoliquids is one of the challenges in these applications of microfluidics. Therefore, using single wall carbon nanotubes for enhancement of thermal energy in microchannel is the main purpose of this study. Hall effect of natural convection flow in a vertical channel with slip and temperature jump condition is considered. The impacts of radiative heat flux, uniform heat source/sink, viscous dissipation and joule heating are also taken into account. Design/methodology/approach Suitable non-dimension variables are applied to the governing equations to reduce the system into ordinary differential equations. The reduced nonlinear system is then solved numerically using Runge–Kutta–Fehlberg fourth–fifth-order method along with shooting technique. The impact of different pertinent parameters on numerical solutions of primary velocity, secondary velocity, temperature, entropy generation and Bejan number is comprehensively discussed in detail. Also, the obtained numerical results are compared with existing one which perfectly found to be in good agreement. Findings It is established that, with the aspects of Joule heating, viscous dissipation, radiative heat flux and uniform heat source/sink, the production in the entropy can be improved. Further, it is found that the increasing ratio of wall ambient temperature difference and nanoparticle volume fraction leads to enhance the entropy generation. The same effect reverses with increasing values of fluid wall interaction parameter (FWIP) and rare faction. The irreversibility ratio enhances with larger values of nanoparticle volume fraction and decelerates with increment values of FWIP. Originality/value The impact of single wall carbon nanoliquid in a vertical channel flow by using radiative heat flux, heat source/sink, joule heating and viscous dissipation is first time investigated. Further, the influence of Hall current is explored in detail.

MHD micropolar nanofluid flow through an inclined channel with entropy generation subjected to radiative heat flux, viscous dissipation and multiple slip effects

2020 ◽  
Vol 16 (6) ◽  
pp. 1475-1496
Author(s):  
A. Roja ◽  
B.J. Gireesha ◽  
B.C. Prasannakumara
Keyword(s):  
Heat Flux ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Radiative Heat ◽  
Radiative Heat Flux ◽  
Nanofluid Flow ◽  
Content Type ◽  
Inclined Channel ◽  
Micropolar Nanofluid ◽  
Flow Through

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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