Unsteady MHD stagnation-point flow with heat and mass transfer for a three-dimensional porous body in the presence of heat generation/absorption and chemical reaction

2011 ◽  
Vol 11 (6) ◽  
pp. 388 ◽  
Author(s):  
Ali J. Chamkha ◽  
Sameh E. Ahmed
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Stagnation Point ◽  
Chemical Reaction ◽  
Heat Generation ◽  
Porous Body ◽  
Three Dimensional ◽  
Stagnation Point Flow

Unsteady convective heat and mass transfer of a nanofluid in Howarth’s stagnation point by Buongiorno’s model

2015 ◽  
Vol 25 (5) ◽  
pp. 1176-1197 ◽  
Author(s):  
Saeed Dinarvand ◽  
Reza Hosseini ◽  
Ioan Pop
Keyword(s):  
Mass Transfer ◽  
Nusselt Number ◽  
Brownian Motion ◽  
Heat And Mass Transfer ◽  
Stagnation Point ◽  
Three Dimensional ◽  
Stagnation Point Flow ◽  
Content Type ◽  
Buongiorno’S Model ◽  
Brownian Motion And Thermophoresis

Purpose – The purpose of this paper is to do a comprehensive study on the unsteady general three-dimensional stagnation-point flow and heat transfer of a nanofluid by Buongiorno’s model. Design/methodology/approach – In this study, the convective transport equations include the effects of Brownian motion and thermophoresis. By introducing new similarity transformations for velocity, temperature and nanoparticle volume fraction, the basic equations governing the flow, heat and mass transfer are reduced into highly non-linear ordinary differential equations. The resulting non-linear system has been solved both analytically and numerically. Findings – The analysis shows that velocity, temperature and nanoparticle concentration profiles in the respective boundary layers depend on five parameters, namely unsteadiness parameter A, Brownian motion parameter Nb, thermophoresis parameter Nt, Prandtl number Pr and Lewis number Le. It is found that the thermal boundary layer thickens with a rise in both of the Brownian motion and the thermophoresis effects. Therefore, similar to the earlier reported results, the Nusselt number decreases as the Brownian motion and thermophoresis effects become stronger. A correlation for the Nusselt number has been developed based on a regression analysis of the data. This correlation predicts the numerical results with a maximum error of 9 percent for a usual domain of the physical parameters. Originality/value – The stagnation point flow toward a wavy cylinder (with nodal and saddle stagnation points) that a little attention has been given to it up to now. The examination of unsteadiness effect on the general three-dimensional stagnation-point flow. The application of an interesting and global model (Boungiorno’s model) for the nanofluid that incorporates the effects of Brownian motion and thermophoresis. The study of the effects of Brownian motion and thermophoresis on the nanofluid flow, heat and mass transfer characteristics. The prediction of correlation for the Nusselt number based on a regression analysis of the data. General speaking, we can tell the problem with this geometry, characteristics, the applied model, and comprehensive results, was Not studied and analyzed in literature up to now.

scholarly journals Lie group analysis for the effects of chemical reaction on MHD stagnation-point flow of heat and mass transfer towards a heated porous stretching sheet with suction or injection

2012 ◽  
Vol 17 (1) ◽  
pp. 1-15 ◽  
Author(s):  
Ahmed A. Afify ◽  
Nasser S. Elgazery
Keyword(s):  
Differential Equation ◽  
Mass Transfer ◽  
Ordinary Differential Equation ◽  
Heat And Mass Transfer ◽  
Stagnation Point ◽  
Chemical Reaction ◽  
Stretching Sheet ◽  
Stagnation Point Flow ◽  
Order Ordinary Differential Equation ◽  
Suction Or Injection

An analysis is carried out to study two dimensional stagnation-point flow of heat and mass transfer of an incompressible, electrically conducting fluid towards a heated porous stretching sheet embedded in a porous medium in the presence of chemical reaction, heat generation/absorption and suction or injection effects. A scaling group of transformations is applied to the governing equations. After finding three absolute invariants a third order ordinary differential equation corresponding to the momentum equation and two second order ordinary differential equation corresponding to energy and diffusion equations are derived. Furthermore the similarity equations are solved numerically by using shooting technique with fourth-order Runge–Kutta integration scheme. A comparison with known results is excellent. The phenomenon of stagnation-point flow towards a heated porous stretching sheet in the presence of chemical reaction, suction or injection with heat generation/absorption effects play an important role on MHD heat and mass transfer boundary layer. The results thus obtained are presented graphically and discussed.

Discussion on Quartic Autocatalytic Kind of Chemical Reaction

2019 ◽  
Author(s):  
Isaac L. Animasaun
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Stagnation Point ◽  
Chemical Reaction ◽  
Real Life ◽  
Stagnation Point Flow ◽  
Unpublished Paper ◽  
Sisko Fluid ◽  
Entropy Optimization ◽  
Published Paper

The significance of chemical reaction is inevitable and there exist many kinds in real life. Recently, the concept of quartic autocatalytic kind of chemical reaction was appraised (Refs. [10] – [16]). It is worth remarking that the concept had been wrongly used in a recently published paper. To avoid confusion, this unpublished paper is presented for clarification. In the report “entropy optimization and quartic autocatalysis in MHD chemically reactive stagnation point flow of Sisko nanomaterial, International Journal of Heat and Mass Transfer <a>127</a>, <a>829</a> – <a>837</a>”, the author investigated cubic autocatalytic kind of chemical reaction between non-Newtonian Sisko fluid and two molecules of catalyst situated at the surface. However, in three different places including the title, the author claimed that the reaction is quartic autocatalysis.<br>

Sign in / Sign up

Export Citation Format

Share Document