scholarly journals Entropy generation and activation energy mechanism in nonlinear radiative flow of Sisko nanofluid: rotating disk

Heliyon ◽  
2019 ◽  
Vol 5 (6) ◽  
pp. e01863 ◽  
Author(s):  
M. Ijaz ◽  
M. Ayub ◽  
H. Khan
2021 ◽  
Vol 13 (3) ◽  
pp. 168781402110065
Author(s):  
Hu Ge-JiLe ◽  
Sumaira Qayyum ◽  
Faisal Shah ◽  
M Ijaz Khan ◽  
Sami Ullah Khan

The growing development in the thermal engineering and nano-technology, much attention has been paid on the thermal properties of nanoparticles which convey many applications in industrial, technological and medical era of sciences. The noteworthy applications of nano-materials included heat transfer enhancement, thermal energy, solar systems, cooling of electronics, controlling the heat mechanisms etc. Beside this, entropy generation is an optimized scheme which reflects significances in thermodynamics systems to control the higher energy efficiency. On this end, present work presents the slip flow of Jeffrey nanofluid over a stretching sheet with applications of activation energy and viscous dissipation. The entropy generation features along with Bejan number significance is also addressed in present analysis. Buongiorno model of nanofluid is used to discuss the heat and mass transfer. The formulated flow equations are attained into non-dimensional form. An appropriate ND MATHEMATICA built-in scheme is used to find the solution. The solution confirmation is verified by performing the error analysis. For developed flow model and impacted parameters, a comprehensive graphical analysis is performed. It is observed that slip phenomenon is used to decays the velocity profile. Temperature and concentration are in direct relation with Brownian motion parameter and activation energy respectively. Entropy and Bejan number have same results for greater diffusion parameter.


2010 ◽  
Vol 132 (11) ◽  
Author(s):  
A. Arikoglu ◽  
G. Komurgoz ◽  
I. Ozkol ◽  
A. Y. Gunes

The present work examines the effects of temperature and velocity jump conditions on heat transfer, fluid flow, and entropy generation. As the physical model, the axially symmetrical steady flow of a Newtonian ambient fluid over a single rotating disk is chosen. The related nonlinear governing equations for flow and thermal fields are reduced to ordinary differential equations by applying so-called classical approach, which was first introduced by von Karman. Instead of a numerical method, a recently developed popular semi numerical-analytical technique; differential transform method is employed to solve the reduced governing equations under the assumptions of velocity and thermal jump conditions on the disk surface. The combined effects of the velocity slip and temperature jump on the thermal and flow fields are investigated in great detail for different values of the nondimensional field parameters. In order to evaluate the efficiency of such rotating fluidic system, the entropy generation equation is derived and nondimensionalized. Additionally, special attention has been given to entropy generation, its characteristic and dependency on various parameters, i.e., group parameter, Kn and Re numbers, etc. It is observed that thermal and velocity jump strongly reduce the magnitude of entropy generation throughout the flow domain. As a result, the efficiency of the related physical system increases. A noticeable objective of this study is to give an open form solution of nonlinear field equations. The reduced recurative form of the governing equations presented gives the reader an opportunity to see the solution in open series form.


2021 ◽  
Author(s):  
M R Acharya ◽  
P Mishra ◽  
Satyananda Panda

Abstract This paper analyses the augmentation entropy generation number for a viscous nanofluid flow over a non-isothermal wedge including the effects of non-linear radiation and activation energy. We discuss the influence of thermodynamically important parameters during the study, namely, the Bejan number, entropy generation number, and the augmentation entropy generation number. The mathematical formulation for thermal conductivity and viscosity of nanofluid for Al2O3 − EG mixture has been considered. The results were numerically computed using implicit Keller-Box method and depicted graphically. The important result is the change in augmentation entropy generation number with Reynolds number. We observed that adding nanoparticles (volume fraction) tend to enhance augmentation entropy generation number for Al2O3 − EG nanofluid. Further, the investigation on the thermodynamic performance of non-isothermal nanofluid flow over a wedge reveals that adding nanoparticles to the base fluid is effective only when the contribution of heat transfer irreversibility is more than fluid friction irreversibility. This work also discusses the physical interpretation of heat transfer irreversibility and pressure drop irreversibility. This dependency includes Reynolds number and volume fraction parameter. Other than these, the research looked at a variety of physical characteristics associated with the flow of fluid, heat and mass transfer.


2008 ◽  
Vol 85 (12) ◽  
pp. 1225-1236 ◽  
Author(s):  
Aytac Arikoglu ◽  
Ibrahim Ozkol ◽  
Guven Komurgoz

Author(s):  
Анна Игоревна Пичугина ◽  
Ирина Геннадьевна Критова

В работе представлены результаты математического моделирования окислительного растворения хизлевудита в растворах азотной кислоты в условиях равнодоступной поверхности вращающегося диска с применением метода полного факторного эксперимента. Получены и проанализированы зависимости скорости процесса гидрохимического окисления сульфида никеля (W, моль/смс) от продолжительности взаимодействия (τ, с), влияния концентрации азотной кислоты (С, моль/дм), частоты вращения диска (ω, с) и температуры (Т, К). Определены основные кинетические параметры: константа скорости и эффективная энергия активации процесса. Установлены режимы взаимодействия хизлевудита с азотной кислотой, выявлены вероятные лимитирующие стадии взаимодействия. The paper presents the results of mathematical modeling of the oxidative dissolution of hizlewudite in solutions of nitric acid using the rotating disk method and the factor experimental design. The dependences of specific speed of dissolution of sulfide of nickel Nickel sulfide (W, mol/cmc) on the duration of interaction (τ, s), the influence of nitric acid concentration (C, mol/dm), frequencies of rotation disk (ω, s) and temperatures (T, K) were obtained and analyzed. The main kinetic parameters are determined: the rate constant and the activation energy of the process. Established modes of interaction heazlewoodite with nitric acid, identified probable limiting stage of the interaction.


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