Effect of convective boundary condition on unsteady flow of CNT-H2O nanofluid towards a stagnation-point on a shrinking/expanding flat sheet

2021 ◽  
pp. 095440892110546
Author(s):  
Sohita Rajput ◽  
Amit Kumar Pandey ◽  
Krishnendu Bhattacharyya ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Carbon Nanotubes ◽  
Boundary Condition ◽  
Stagnation Point ◽  
Numerical Solutions ◽  
Volume Fraction ◽  
Convective Boundary Condition ◽  
Dual Solutions ◽  
Convective Boundary ◽  
Walled Carbon Nanotubes

A model study of unsteady stagnation-point flow of most important nanoparticles, that is, carbon nanotubes suspended nanofluid towards shrinking/expanding sheet with convective boundary condition is demonstrated. Two types of carbon nanotubes, namely, single-wall and multi-wall nanotubes are carefully considered. Numerical solutions of converted equations from governing equation of the problem are obtained and those are graphically presented. Similar to without carbon nanotubes case, dual and unique solutions in specific ranges of velocity ratio parameter are achieved. Analysis disclosures that the condition on range where dual solutions exist is unaltered with solid-volume fraction and type of carbon nanotubes. The surface drag-force and heat transfer rate from wall are larger for single-walled carbon nanotubes nanofluid than multi-walled carbon nanotubes nanofluid. An increment in the parameter related to convective boundary condition generates high rate of heat transfer. After stability analysis, it is identified that in case of dual solutions, upper branch is stable and lower branch is unstable, while unique solution is always stable.

INFLUENCE OF HEAT TRANSFER ON THE MHD STAGNATION POINT FLOW OF A POWER LAW FLUID WITH CONVECTIVE BOUNDARY CONDITION

2015 ◽  
Vol 77 (20) ◽  
Author(s):  
Shah Jahan ◽  
Hamzah Sakidin
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Differential Equations ◽  
Stagnation Point ◽  
Power Law ◽  
Convective Boundary Condition ◽  
Stagnation Point Flow ◽  
Power Law Fluid ◽  
Convective Boundary ◽  
The Impact

In this article, we examined the impact of heat transfer on the magnetohydrodynamic (MHD) stagnation point flow of a non-Newtonian power- law fluid with convective boundary condition. By using suitable similarity transformations, coupled nonlinear partial differential equations are transformed to ordinary differential equations. Then solved the resulting equations with Homotopy analysis method.  Interesting flow parameters such as MHD , stagnation parameter  convective parameter  are discussed graphically. Convergence is checked at 20th order of approximation. Numerical values of physical interested parameter such as local Nusselt number are also tabulated.

scholarly journals Flow and Heat Transfer of MHD Dusty Nanofluid Toward Moving Plate with Convective Boundary Condition

2021 ◽  
Vol 89 (2) ◽  
pp. 43-55
Author(s):  
Euwing Low ◽  
Syahira Mansur ◽  
Yaan Yee Choy ◽  
Eugene Low
Keyword(s):  
Heat Transfer ◽  
Boundary Condition ◽  
Differential Equations ◽  
Volume Fraction ◽  
Particle Interaction ◽  
Convective Boundary Condition ◽  
Moving Plate ◽  
Convective Boundary ◽  
Linear Ordinary Differential Equations ◽  
Flow And Heat Transfer

This paper considers the flow and heat transfer characteristics of dusty nanofluid over a moving plate in the presence of magnetohydrodynamic (MHD) with convective boundary condition. Two types of nanofluid namely CuO-water and Al2O3-water permeated with dust particles are considered. The governing partial differential equations are converted into a system of non-linear ordinary differential equations using similarity transformation, then the non-linear ordinary differential equations are solved using shooting method with fourth-fifth order Runge-Kutta Fehlberg method (RKF45). The influence of non-dimensional governing parameters such as velocity ratio parameter, magnetic field parameter, volume fraction of the nanoparticle, volume fraction of the dust particle, mass concentration of the dust particle, fluid particle interaction parameter for velocity, fluid particle interaction parameter for temperature and Biot number on the velocity and temperature profiles for fluid and dust phases of CuO-water and Al2O3-water dusty nanofluids are discussed and presented through graphs. The skin friction coefficient and Nusselt number are discussed and presented in tabular form.

Numerical solutions of non-alignment stagnation-point flow and heat transfer over a stretching/shrinking surface in a nanofluid

2016 ◽  
Vol 26 (6) ◽  
pp. 1747-1767 ◽  
Author(s):  
Ioan Pop ◽  
Kohi Naganthran ◽  
Roslinda Nazar
Keyword(s):  
Heat Transfer ◽  
Differential Equations ◽  
Stagnation Point ◽  
Numerical Solutions ◽  
Dual Solutions ◽  
Stagnation Point Flow ◽  
Content Type ◽  
Boundary Layer Equations ◽  
Flow And Heat Transfer ◽  
Shrinking Surface

Purpose – The purpose of this paper is to analyse numerically the steady stagnation-point flow of a viscous and incompressible fluid over continuously non-aligned stretching or shrinking surface in its own plane in a water-based nanofluid which contains three different types of nanoparticles, namely, Cu, Al2O3 and TiO2. Design/methodology/approach – Similarity transformation is used to convert the system of boundary layer equations which are in the form of partial differential equations into a system of ordinary differential equations. The system of similarity governing equations is then reduced to a system of first-order differential equations and solved numerically using the bvp4c function in Matlab software. Findings – Unique solution exists when the surface is stretched and dual solutions exist as the surface shrunk. For the dual solutions, stability analysis has revealed that the first solution (upper branch) is stable and physically realizable, while the second solution (lower branch) is unstable. The effect of non-alignment is huge for the shrinking surface which is in contrast with the stretching surface. Practical implications – The results obtained can be used to explain the characteristics and applications of nanofluids, which are widely used as coolants, lubricants, heat exchangers and micro-channel heat sinks. This problem also applies to some situations such as materials which are manufactured by extrusion, production of glass-fibre and shrinking balloon. In this kind of circumstance, the rate of cooling and the stretching/shrinking process play an important role in moulding the final product according to preferable features. Originality/value – The present results are original and new for the study of fluid flow and heat transfer over a stretching/shrinking surface for the problem considered by Wang (2008) in a viscous fluid and extends to nanofluid by using the Tiwari and Das (2007) model.

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