Transient Velocity And Steady State Entropy Generation In A Microfluidic Couette Flow Containing Charged Nano Particles

2020

HFF

Self Cite

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.

Section: Hall Effect Of Natural Convection Flowmentioning

confidence: 99%

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

Roja

2020

HFF

Self Cite

“…The convergence criteria and step size are chosen as 10 À6 and r ¼ 0:001. From the process of numerical computation, we obtain the entropy generation rate, and the Bejan number as given by equations (11) and (12).…”

Section: Solution Proceduresmentioning

confidence: 99%

“…The transient velocity and steady state entropy generation in a microfluidic Couette flow influenced by the electro-kinetic effect of charged nanoparticles has been studied by Gorla and Gireesha. 12 Ranjit and Shit 13 developed a mathematical model for electromagnetohydrodynamic flow of biofluids over a hydrophobic microchannel with different zeta potential and expanding walls under the influence of an axially applied electric field. In this direction, various investigators [14][15][16][17] have explored the importance of fluid flow in microchannels.…”

Section: Introductionmentioning

confidence: 99%

Entropy generation and heat transport analysis of Casson fluid flow with viscous and Joule heating in an inclined porous microchannel

Proceedings of the Institution of Mechanical Engineers, Part E:

Srinivasa

Shashikumar

et al. 2019

The combined effects of the magnetic field, suction/injection, and convective boundary condition on heat transfer and entropy generation in an electrically conducting Casson fluid flow through an inclined porous microchannel are scrutinized. The temperature-dependent heat source is also accounted. Numerical simulation for the modelled problem is presented via Runge–Kutta–Felhberg-based shooting technique. Special attention is given to analyze the impact of involved parameters on the profiles of velocity [Formula: see text], temperature [Formula: see text], entropy generation [Formula: see text], and Bejan number [Formula: see text]. It is established that entropy generation rate decreases at the walls with an increase in Hartmann number [Formula: see text], while it increases at the center region of the microchannel.

“…They have interestingly noticed that the thermal conductivity ratio from the porous medium to the solid part may enhance or decelerate the fluid friction irreversibility with the dependency of the channel boundary condition. The entropy generation and transient velocity in microfluidic Couette flow in a steady state has been investigated by Gorla and Gireesha (2015). They have discussed the influence of irreversibility ratio, fluid friction irreversibility and heat transfer on the height of the channel, Brinkman number, ratio of dimensionless temperature and nanoparticle volume fraction.…”

Section: Introductionmentioning

confidence: 99%

Second law analysis of MHD natural convection slip flow of Casson fluid through an inclined microchannel

Roja

2020

MMMS

Self Cite

PurposeMicrofluidics is one of the interesting areas of the research in thermal and engineering fields due to its wide range of applications in a variety of heat transport problems such as micromixers, micropumps, cooling systems for microelectromechanical systems (MEMS) micro heat exchangers, etc. Lower cost with better thermal performance is the main objective of these devices. Therefore, in this study, the entropy generation in an electrically conducting Casson fluid flow through an inclined microchannel with hydraulic slip and the convective condition hves been numerically investigated. Aspects of viscous dissipation, natural convection, joule heating, magnetic field and uniform heat source/sink are usedDesign/methodology/approachSuitable non-dimensional variables are used to reduce the non-linear system of ordinary differential equations, and then this system is solved numerically using Runge-Kutta-Fehlberg fourth fifth order method along with shooting technique. The obtained numerical solutions of the fluid velocity and temperature are used to characterize the entropy generation and Bejan number. Also, the Nusselt number and skin friction coefficient for various values of parameters are examined in detail through graphs. The obtained present results are compared with the existing one which is perfectly found to be in good agreement.FindingsIt is established that the production of the entropy can be improved with the aspects of joule heating, viscous dissipation and internal heat source/sink. The entropy generation enhances for increasing values of Casson Parameter (β) and Biot number (Bi). Furthermore, it is interestingly noticed that the enhancement of Reynolds number and uniform heat source/sink shows the dual behaviour of the entropy generation due to significant influence of the viscous forces in the region close to the channel walls. It was observed that increasing behaviour of the heat transfer rate for enhancement values of the Eckert number and heat source/sink ratio parameter and the drag force are retarded with higher estimations of Reynolds number.Originality/valueEntropy generation analysis on MHD Casson fluid flow through an inclined microchannel with the aspects of convective, Joule heating, viscous dissipation, magnetism, hydraulic slip and internal heat source/sink has been numerically investigated.