scholarly journals Entropy Generation on Nanofluid Flow through a Horizontal Riga Plate

Entropy ◽  
2016 ◽  
Vol 18 (6) ◽  
pp. 223 ◽  
Author(s):  
Tehseen Abbas ◽  
Muhammad Ayub ◽  
Muhammad Bhatti ◽  
Mohammad Rashidi ◽  
Mohamed Ali
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.


2020 ◽  
Vol 45 (3) ◽  
pp. 257-268 ◽  
Author(s):  
Lijun Zhang ◽  
Muhammad Mubashir Bhatti ◽  
Rahmat Ellahi ◽  
Efstathios E. Michaelides

AbstractThe aim of this paper is to analyze the behavior of oxytactic microorganisms and thermo-bioconvection nanofluid flow through a Riga plate with a Darcy–Brinkman–Forchheimer porous medium. The Riga plate is composed of electrodes and magnets that are placed on a plane. The fluid is electrically conducting, and the Lorentz force evolves exponentially along the vertical direction. The governing equations are formulated with the help of dimensionless variables. With the aid of a shooting scheme, the numerical results are presented in graphs and tables. It is noted that the modified Hartmann number boosts the velocity profile when it is positive, but lowers these values when it is negative. The density-based Rayleigh number and the nanoparticle concentration enhance the fluid velocity. The thermal Rayleigh number and the Darcy–Forchheimer number decrease the velocity. An increase in Lewis number causes a remarkable decline in the oxytactic microorganism profile. Several useful results for these flows with oxytactic microorganisms through Darcy–Brinkman–Forchheimer porous media are presented in this paper.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Muhammad Rooman ◽  
Muhammad Asif Jan ◽  
Zahir Shah ◽  
Poom Kumam ◽  
Ahmed Alshehri

AbstractThe entropy generation for a reactive Williamson nanofluid flow past a vertical Riga system is the subject of this article. The effects of MHD, thermophoresis, nonlinear heat radiation and varying heat conductivity are modeled into the heat equation in the established model. Suitable similarity transformations are examined to bring down the partial differential equations into ordinary differential equations. The Homotopy analysis approach is used to solve the dimensionless transport equations analytically. The graphic information of the various parameters that emerged from the model is effectively collected and deliberated. The temperature field expands with thermophoresis, Brownian motion and temperature ratio parameters as the modified Hartmann number forces an increase in velocity, according to the findings of this analysis. With the increase in the fluid material terms, the entropy generation and Bejan number increase. Riga plate has numerous applications in improving the thermo-physics features of a fluid, the value of magnetic field embraces an important role in fluid mechanics. An external electric field can be used to control flow in weak electrically conductive fluids. The Riga plate is one of the devices used in this regard. It’s a device that creates electromagnetic fields. They produce the Lorentz force which is a force that directs fluid flow. The authors have discussed the entropy optimization for a reactive Williamson nanofluid flow past a vertical Riga plate is addressed. This is the first investigation on mass and heat transfer flow that the authors are aware of, and no similar work has yet been published in the literature. A thorough mathematical examination is also required to demonstrate the model’s regularity. The authors believe that the results acquired are novel and have not been plagiarized from any other sources.


2020 ◽  
Vol 95 (11) ◽  
pp. 115004
Author(s):  
Yu-Ming Chu ◽  
Faisal Shah ◽  
M Ijaz Khan ◽  
Shabnam Farooq ◽  
Seifedine Kadry ◽  
...  

Entropy ◽  
2020 ◽  
Vol 22 (9) ◽  
pp. 1008
Author(s):  
Ehsan Aminian ◽  
Hesam Moghadasi ◽  
Hamid Saffari ◽  
Amir Mirza Gheitaghy

Corrugating channel wall is considered to be an efficient procedure for achieving improved heat transfer. Further enhancement can be obtained through the utilization of nanofluids and porous media with high thermal conductivity. This paper presents the effect of geometrical parameters for the determination of an appropriate configuration. Furthermore, the optimization of forced convective heat transfer and fluid/nanofluid flow through a sinusoidal wavy-channel inside a porous medium is performed through the optimization of entropy generation. The fluid flow in porous media is considered to be laminar and Darcy–Brinkman–Forchheimer model has been utilized. The obtained results were compared with the corresponding numerical data in order to ensure the accuracy and reliability of the numerical procedure. As a result, increasing the Darcy number leads to the increased portion of thermal entropy generation as well as the decreased portion of frictional entropy generation in all configurations. Moreover, configuration with wavelength of 10 mm, amplitude of 0.5 mm and phase shift of 60° was selected as an optimum geometry for further investigations on the addition of nanoparticles. Additionally, increasing trend of average Nusselt number and friction factor, besides the decreasing trend of performance evaluation criteria (PEC) index, were inferred by increasing the volume fraction of the nanofluid (Al2O3 and CuO).


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