Examination of carbon-water nanofluid flow with thermal radiation under the effect of Marangoni convection

2017 ◽  
Vol 34 (7) ◽  
pp. 2330-2343 ◽  
Author(s):  
Syed Tauseef Mohyud-Din ◽  
Muhammad Usman ◽  
Kamran Afaq ◽  
Muhammad Hamid ◽  
Wei Wang
Keyword(s):  
Boundary Layer ◽  
Thermal Radiation ◽  
Least Squares ◽  
Marangoni Convection ◽  
Volume Fraction ◽  
Least Squares Method ◽  
Detailed Comparison ◽  
Convection Boundary Layer ◽  
Nanoparticle Volume Fraction ◽  
Content Type

Purpose The purpose of this study is to analyze the effects of carbon nanotubes (CNTs) in the Marangoni convection boundary layer viscous fluid flow. The analysis and formulation for both types of CNTs, namely, single-walled (SWCNTs) and multi-walled (MWCNTs), are described. The influence of thermal radiation effect assumed in the form of energy expression. Design/methodology/approach Appropriate transformations reduced the partial differential systems to a set of nonlinear ordinary differential equations (ODEs). The obtained nonlinear ODE set is solved via the least squares method. A detailed comparison between outcomes obtained by the least squares method, RK-4 and already published work is available. Findings Nusselt number was analyzed and found to be more effective for nanoparticle volume fraction and larger radiation parameters. Additionally, the error and convergence analysis for the least squares method was presented to show the efficiency of the said algorithm. Originality/value The results reveal that velocity is a decreasing function of suction for both CNTs. While enhancing the nanoparticle volume fraction, an increase for both thermal boundary layer thickness and temperature was attained. The radiation parameter has an increasing function as temperature. Velocity behavior is the same for nanoparticle volume fraction and suction. It was observed that velocity is less in SWCNTs as compared to MWCNTs.

Mixed convection boundary layer flow from a vertical truncated cone in a nanofluid

2014 ◽  
Vol 24 (5) ◽  
pp. 1175-1190 ◽  
Author(s):  
F.O. Pătrulescu ◽  
T. Groşan ◽  
I. Pop
Keyword(s):  
Boundary Layer ◽  
Mixed Convection ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Convection Boundary Layer ◽  
Particle Volume ◽  
Content Type ◽  
Mixed Convection Parameter ◽  
Layer Flow ◽  
Convection Parameter

Purpose – The purpose of this paper is to investigate the steady mixed convection boundary layer flow from a vertical frustum of a cone in water-based nanofluids. The problem is formulated to incorporate three kinds of nanoparticles: copper, alumina and titanium oxide. The working fluid is chosen as water with the Prandtl number of 6.2. The mathematical model used for the nanofluid incorporates the particle volume fraction parameter, the effective viscosity and the effective thermal diffusivity. The entire regime of the mixed convection includes the mixed convection parameter, which is positive for the assisting flow (heated surface of the frustum cone) and negative for the opposing flow (cooled surface of the frustum cone), respectively. Design/methodology/approach – The transformed non-linear partial differential equations are solved numerically for some values of the governing parameters. The derivatives with respect to? were discretized using the first order upwind finite differences and the resulting ordinary differential equations with respect to? were solved using bvp4c routine from Matlab. The absolute error tolerance in bvp4c was 1e-9. Findings – The features of the flow and heat transfer characteristics for different values of the governing parameters are analysed and discussed. The effects of the particle volume fraction parameter \phi, the mixed convection parameter \lambda and the dimensionless coordinate? on the flow and heat transfer characteristics are determined only for the Cu nanoparticles. It is found that dual solutions exist for the case of opposing flows. The range of the mixed convection parameter for which the solution exists increases in the presence of the nanofluids. Originality/value – The paper models the mixed convection from a vertical truncated cone using the boundary layer approximation. Multiple (dual) solutions for the flow reversals are obtained and the range of existence of the solutions was found. Particular cases for ?=0 (full cone), ? >>1 and (free convection limit) \lambda>>1were studied. To the authors best knowledge this problem has not been studied before and the results are new and original.

Mixed convection boundary layer flow along vertical thin needles in nanofluids

2014 ◽  
Vol 24 (3) ◽  
pp. 579-594 ◽  
Author(s):  
Radu Trimbitas ◽  
Teodor Grosan ◽  
Ioan Pop
Keyword(s):  
Heat Transfer ◽  
Boundary Layer ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Convection Boundary Layer ◽  
Heat Transfer Characteristics ◽  
Content Type ◽  
Flow And Heat Transfer ◽  
Convection Boundary ◽  
Layer Flow

Purpose – The purpose of this paper is to theoretically study the problem of mixed convection boundary layer flow and heat transfer past a vertical needle with variable wall temperature using nanofluids. The similarity equations are solved numerically for copper nanoparticles in the based fluid of water to investigate the effect of the solid volume fraction parameter of the fluid and heat transfer characteristics. The skin friction coefficient, Nusselt number, and the velocity and temperature profiles and are graphically presented and discussed. Design/methodology/approach – The transformed system of ordinary differential equations was solved using the function bvp4c from Matlab. The relative tolerance was set to 1e-10. For the study of the stability the authors also used the bvp4c function in combination with chebfun package from Matlab. Findings – It is found that the solid volume fraction affects the fluid flow and heat transfer characteristics. The numerical results for a regular fluid and forced convection flow are compared with the corresponding results reported by Chen and Smith. The solutions exists up to a critical value of λ, beyond which the boundary layer separates from the surface and the solution based upon the boundary-layer approximations is not possible Originality/value – The paper describes how multiple (dual) solutions for the flow reversals are obtained. A stability analysis for this flow reversal has been also done showing that the lower solution branches are unstable, while the upper solution branches are stable.

Transient two-dimensional natural convection flow of a nanofluid past an isothermal vertical plate using Buongiorno’s model

2017 ◽  
Vol 27 (1) ◽  
pp. 23-47 ◽  
Author(s):  
Marneni Narahari ◽  
Suresh Kumar Raju Soorapuraju ◽  
Rajashekhar Pendyala ◽  
Ioan Pop
Keyword(s):  
Boundary Layer ◽  
Nusselt Number ◽  
Brownian Motion ◽  
Natural Convection ◽  
Vertical Plate ◽  
Volume Fraction ◽  
Convection Flow ◽  
Nanoparticle Volume Fraction ◽  
Natural Convection Flow ◽  
Content Type

Purpose The purpose of this paper is to present a numerical investigation of the transient two-dimensional natural convective boundary-layer flow of a nanofluid past an isothermal vertical plate by incorporating the effects of Brownian motion and thermophoresis in the mathematical model. Design/methodology/approach The problem is formulated using the Oberbeck–Boussinesq and the standard boundary-layer approximations. The governing coupled non-linear partial differential equations for conservation of mass, momentum, thermal energy and nanoparticle volume fraction have been solved by using an efficient implicit finite-difference scheme of the Crank–Nicolson type, which is stable and convergent. Numerical computations are performed and the results for velocity, temperature and nanoparticle volume fraction are presented in graphs at different values of system parameters such as Brownian motion parameter, thermophoresis parameter, buoyancy ratio parameter, Prandtl number, Lewis number and dimensionless time. The results for local and average skin-friction and Nusselt number are also presented graphically and discussed thoroughly. Findings It is found that the velocity, temperature and nanoparticle volume fraction profiles enhance with respect to time and attain steady-state values as time progresses. The local Nusselt number is found to decrease with increasing thermophoresis parameter, while it increases slightly with increasing Brownian motion parameter. To validate the present numerical results, the steady-state local Nusselt number results for the limiting case of a regular fluid have been compared with the existing well-known results at different Prandtl numbers, and the results are found to be in an excellent agreement. Research limitations/implications The present analysis is limited to the transient laminar natural convection flow of a nanofluid past an isothermal semi-infinite vertical plate in the absence of viscous dissipation and thermal radiation. The unsteady natural convection flow of a nanofluid will be investigated for various physical conditions in a future work. Practical implications Unsteady flow devices offer potential performance improvements as compared with their steady-state counterparts, and the flow fields in the unsteady flow devices are typically transient in nature. The present study provides very useful information for heat transfer engineers to understand the heat transfer enhancement with the nanofluid flows. The present results have immediate relevance in cooling technologies. Originality/value The present research work is relatively original and illustrates the transient nature of the natural convective nanofluid boundary-layer flow in the presence of Brownian motion and thermophoresis.

scholarly journals The effect of thermal radiation, heat generation and suction/injection on the mechanical properties of unsteady continuous moving cylinder in a nanofluid

2015 ◽  
Vol 19 (5) ◽  
pp. 1591-1601 ◽  
Author(s):  
El-Sayed El-Bashbeshy ◽  
Tarek Emam ◽  
Mohamed Abdel-Wahed
Keyword(s):  
Mechanical Properties ◽  
Boundary Layer ◽  
Thermal Radiation ◽  
Heat Generation ◽  
Volume Fraction ◽  
Nanoparticle Volume Fraction ◽  
Radiation Heat ◽  
Cooling Medium ◽  
Moving Cylinder ◽  
Radiation Heat Generation

The effect of thermal radiation, heat generation, suction/injection, nanoparticles type, and nanoparticle volume fraction on heat transfer characteristics and the mechanical properties of unsteady moving cylinder embedded into cooling medium consist of water with Cu; Ag or Al2O3 particles are studied. The governing time dependent boundary layer equations are transformed to ordinary differential equations containing unsteadiness parameter, thermal radiation parameter, heat source parameter, suction/injection parameter, curvature parameter, nanoparticle volume fraction and Prandlt number. These equations are solved numerically. The velocity and Temperature profiles within the boundary layer are plotted and discussed in details for various values of the different parameters. Also the effects of the cooling medium and the external thermal forces on the mechanical properties of the cylinder are investigated.

scholarly journals Magneto-bioconvection flow of a casson thin film with nanoparticles over an unsteady stretching sheet

2019 ◽  
Vol 29 (11) ◽  
pp. 4277-4309 ◽  
Author(s):  
Atul Kumar Ray ◽  
Vasu B. ◽  
O. Anwar Beg ◽  
R.S.R. Gorla ◽  
P.V.S.N. Murthy
Keyword(s):  
Thin Film ◽  
Boundary Layer ◽  
Layer Thickness ◽  
Boundary Layer Thickness ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Numerical Technique ◽  
Nano Particle ◽  
Nanoparticle Volume Fraction ◽  
Content Type

PurposeThis paper aims to numerically investigate the two-dimensional unsteady laminar magnetohydrodynamic bioconvection flow and heat transfer of an electrically conducting non-Newtonian Casson thin film with uniform thickness over a horizontal elastic sheet emerging from a slit in the presence of viscous dissipation. The composite effects of variable heat, mass, nanoparticle volume fraction and gyrotactic micro-organism flux are considered as is hydrodynamic (wall) slip. The Buongiorno nanoscale model is deployed which features Brownian motion and thermophoresis effects. The model studies the manufacturing fluid dynamics of smart magnetic bio-nano-polymer coatings.Design/methodology/approachThe coupled non-linear partial differential boundary-layer equations governing the flow, heat and nano-particle and micro-organism mass transfer are reduced to a set of coupled non-dimensional equations using the appropriate transformations and then solved as an nonlinear boundary value problem with the semi-numerical Liao homotopy analysis method (HAM).Validation with a generalized differential quadrature (GDQ) numerical technique is included.FindingsAn increase in velocity slip results in a significant decrement in skin friction coefficient and Sherwood number, whereas it generates a substantial enhancement in Nusselt number and motile micro-organism number density. The computations reveal that the bioconvection Schmidt number decreases the micro-organism concentration and boundary-layer thickness which is attributable to a rise in viscous diffusion rate. Increasing bioconvection Péclet number substantially elevates the temperatures in the regime, thermal boundary layer thickness, nanoparticle concentration values and nano-particle species boundary layer thickness. The computations demonstrate the excellent versatility of HAM and GDQ in solving nonlinear multi-physical nano-bioconvection flows in thermal sciences and furthermore are relevant to application in the synthesis of smart biopolymers, microbial fuel cell coatings, etc.Research limitations/implicationsThe numerical study is valid for two-dimensional, unsteady, laminar Casson film flow with nanoparticles over an elastic sheet in presence of variable heat, mass and nanoparticle volume fraction flux. The film has uniform thickness and flow is transpiring from slit which is fixed at origin.Social implicationsThe study has significant applications in the manufacturing dynamics of nano-bio-polymers and the magnetic field control of materials processing systems. Furthermore, it is relevant to application in the synthesis of smart biopolymers, microbial fuel cell coatings, etc.Originality/valueThe originality of the study is to address the simultaneous effects of unsteady and variable surface fluxes on Casson nanofluid transport of gyrotactic bio-convection thin film over a stretching sheet in the presence of a transverse magnetic field. Validation of HAM with a GDQ numerical technique is included. The present numerical approaches (HAM and GDQ) offer excellent promise in simulating such multi-physical problems of interest in thermal thin film rheological fluid dynamics.

NUMERICAL SIMULATION OF MARANGONI MAGNETOHYDRODYNAMIC BIO-NANOFLUID CONVECTION FROM A NON-ISOTHERMAL SURFACE WITH MAGNETIC INDUCTION EFFECTS: A BIO-NANOMATERIAL MANUFACTURING TRANSPORT MODEL

2014 ◽  
Vol 14 (03) ◽  
pp. 1450039 ◽  
Author(s):  
O. ANWAR BÉG ◽  
M. FERDOWS ◽  
S. SHAMIMA ◽  
M. NAZRUL ISLAM
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Prandtl Number ◽  
Stream Function ◽  
Magnetic Induction ◽  
Body Force ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Convection Boundary Layer ◽  
Force Parameter

Laminar magnetohydrodynamic Marangoni-forced convection boundary layer flow of a water-based biopolymer nanofluid containing nanoparticles from a non-isothermal plate is studied. Magnetic induction effects are incorporated. A variety of nanoparticles are studied, specifically, silver, copper, aluminium oxide and titanium oxide. The Tiwari–Das model is utilized for simulating nanofluid effects. The normalized ordinary differential boundary layer equations (mass, magnetic field continuity, momentum, induced magnetic field and energy conservation) are solved subject to appropriate boundary conditions using Maple shooting quadrature. The influence of Prandtl number (Pr), magnetohydrodynamic body force parameter (β), reciprocal of magnetic Prandtl number (α) and nanofluid solid volume fraction (φ) on velocity, temperature and magnetic stream function distributions is investigated in the presence of strong Marangoni effects (ξ i.e., Marangoni parameter is set as unity). Magnetic stream function is accentuated with body force parameter. The flow is considerably decelerated as is magnetic stream function gradient, with increasing nanofluid solid volume fraction, whereas temperatures are significantly enhanced. Interesting features in the flow regime are explored. The study finds applications in the fabrication of complex biomedical nanofluids, biopolymers, etc.

scholarly journals Marangoni convection in layers of water-based nanofluids under the effect of rotation

2021 ◽  
Vol 19 (1) ◽  
pp. 1029-1046
Author(s):  
Abeer H. Bakhsh ◽  
Abdullah A. Abdullah
Keyword(s):  
Marangoni Convection ◽  
Volume Fraction ◽  
Steady State Solution ◽  
Horizontal Layer ◽  
Brownian Diffusion ◽  
Nanoparticle Volume Fraction ◽  
Rigid Surface ◽  
Fixed Temperature ◽  
Modified Model ◽  
Conservation Condition

Abstract A linear stability analysis is performed for the onset of Marangoni convection in a horizontal layer of a nanofluid heated from below and affected by rotation. The top boundary of the layer is assumed to be impenetrable to nanoparticles with their distribution being determined from a conservation condition while the bottom boundary is assumed to be a rigid surface with fixed temperature. The motion of the nanoparticles is characterized by the effects of thermophoresis and Brownian diffusion. A modification model is used in which the effects of Brownian diffusion and thermophoresis are taken into consideration by new expressions in the nanoparticle mass flux. Also, material properties of the nanofluid are modelled by non-constant constitutive expressions depending on nanoparticle volume fraction. The steady-state solution is shown to be well approximated by an exponential distribution of the nanoparticle volume fraction. The Chebyshev-Tau method is used to obtain the critical thermal and nanoparticle Marangoni numbers. Different stability boundaries are obtained using the modified model and the rotation.

scholarly journals THERMAL RADIATION EFFECT ON MHD NATURAL CONVECTION BOUNDARY LAYER FLOW OVER A PLATE WITH SUCTION (INJECTION) AND VARIABLE VISCOSITY

2017 ◽  
Vol 5 (4RAST) ◽  
pp. 52-58
Author(s):  
Jalaja P ◽  
Venkataramana B.S ◽  
Naveen V ◽  
K.R. Jayakumar
Keyword(s):  
Magnetic Field ◽  
Boundary Layer ◽  
Natural Convection ◽  
Thermal Radiation ◽  
Boundary Layer Flow ◽  
Variable Viscosity ◽  
Convection Boundary Layer ◽  
Implicit Finite Difference Scheme ◽  
Convection Boundary ◽  
Layer Flow

The effect of thermal radiation on steady natural convection boundary layer flow over a plate with variable viscosity and magnetic field has been studied in this paper. The effect of suction and injection is also considered in the investigation. The system of partial differential equations governing the nonsimilar flow has been solved numerically using implicit finite difference scheme along with a quasilinearization technique. The thermal radiation has significant effect on heat transfer coefficient and thermal transport in presence of viscosity variation parameter and magnetic field in case of suction and injection.

Sign in / Sign up

Export Citation Format

Share Document