scholarly journals The natural convective graphene oxide nanofluid flow in an upright squeezing channel

2019 ◽  
Vol 23 (Suppl. 6) ◽  
pp. 1981-1989 ◽  
Author(s):  
Malik Ullah ◽  
Taza Gul ◽  
Ali Alshomrani ◽  
Dumitru Baleanu

The 3-D flow of water based graphene oxide (GO-W) and ethylene glycol based graphene oxide (GO-EG) nanofluids amongst the binary upright and parallel plates is considered. The unsteady movement of the nanofluid is associated with the porous medium and the unbroken magnetic field is executed in the perpendicular track of the flow field. The basic governing equations have been altered using the Von Karman transformation, including the natural-convection in the downward direction. The solution for the modeled problem has been attained by means of optimal homotopy analysis method (OHAM). The influence of the physical parameters on the momentum boundary-layer, pressure and temperature fields is mainly focused. Moreover, the comparison of the GO-W and GO-EG nanofluids under the impact of physical constraints have been analyzed graphically and numerically. The imperative physical constraints of the drag force and heat transfer rate have been computed and conferred. The consequences have been validated using the error analysis and the obtained outcomes have been shown and discussed.

2019 ◽  
Vol 11 (6) ◽  
pp. 168781401985677 ◽  
Author(s):  
Taza Gul ◽  
Waqas Noman ◽  
Muhammad Sohail ◽  
Muhammad Altaf Khan

The low thermal efficiency of the base liquids is the main issue among the researchers and to resolve this issue, scientists use the small-sized (1–100 nm) metal solid particles in the base liquids to increase the thermal efficiency of the base solvents. In the recent article, a theoretical study has been carried out for the thermal application functioning of graphene-oxide-water-based and graphene-oxide-ethylene-glycol-based nanofluids under the impact of the Marangoni convection. The nanofluid flow is also subjected to thermal radiation and magnetic field. The problem has been solved through optimal homotopy analysis method. The impacts of the embedded parameters over the velocity and temperature pitches have been analysed. Due to strong thermophysical properties of graphene-oxide-ethylene-glycol-based nanofluid, it is observed that the heat transfer rate of this sort of nanofluid is more efficient as compared to the graphene-oxide-water-based nanofluids. All the obtained outputs have been presented graphically and numerically.


Processes ◽  
2019 ◽  
Vol 7 (6) ◽  
pp. 392 ◽  
Author(s):  
Ali Rehman ◽  
Taza Gul ◽  
Zabidin Salleh ◽  
Safyan Mukhtar ◽  
Fawad Hussain ◽  
...  

The gradient of surface temperature is known as Marangoni convection and plays an important role in silicon melt, spray, atomic reactors, and thin fluid films. Marangoni convection has been considered in the liquid film spray of carbon nanotube (CNT) nanofluid over the unsteady extending surface of a cylinder. The two kinds of CNTs, single-wall carbon nanotubes (SWCNTs) and multiple-wall carbon nanotubes (MWCNTs), formulated as water-based nanofluids have been used for thermal spray analysis. The thickness of the nanofluid film was kept variable for a stable spray rate and pressure distribution. The transformed equations of the flow problem have been solved using the optimal homotopy analysis method (OHAM). The obtained results have been validated through the sum of the total residual errors numerically and graphically for both types of nanofluids. The impact of the physical parameters versus velocity, pressure, and temperature pitches under the influence of the Marangoni convection have been obtained and discussed. The obtained results are validated using the comparison of OHAM and the (ND-solve) method.


2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Najeeb Alam Khan ◽  
Faqiha Sultan ◽  
Fatima Riaz ◽  
Muhammad Jamil

Abstract This study is an investigation of fully-developed laminar flow in a two-layer vertical channel; one part filled with couple stress nanofluid and the other part with clear couple stress fluid. The flow is examined for combined heat and mass transfer using uniform wall temperature and concentration boundary conditions. Optimal homotopy analysis method (OHAM) is used to solve the nonlinear coupled ordinary differential equations (ODEs) governing the flow in each region. This method is based on the homotopy analysis method (HAM)which is an effective method to analytically approximate the solution of highly nonlinear problems. The influence of pertinent parameters is observed on velocity, temperature, and concentration distributions, specifically, the effect of Brownian parameter on couple stress fluid is mentioned.


2019 ◽  
Vol 8 (8) ◽  
pp. 1661-1667
Author(s):  
Ali Rehman ◽  
Zabidin Salleh ◽  
Taza Gul

This research paper presents the impact of dynamics viscosity of water base GO–EG (graphene oxide–ethylene glycol)/GO–W (graphene oxide–water) nanofluid over a stretching cylinder with non-porous medium. The impact of different parameter for both velocity and temperature profile are displayed and discussed graphically. The similarity transformation are used to convert the partial differential equation to nonlinear ordinary differential equation. The solution of the problem is obtained using the optimal homotopy analysis method (OHAM). (Liao, S. J., 2010. An optimal homotopy-analysis approach for strongly nonlinear differential equations. Communications in Nonlinear Science and Numerical Simulation, 15, pp.2003–2016) used this method for the solution of nonlinear problem and show that this method is quickly convergent to the approximate solution. This method gives us series solution in the form of function, and all the physical parameters of the problem involved in this method. The stability of the problems is also obtained up to the 30th order approximation using the BVPh 2.0 package. The outputs are displayed graphically and discussed. The effects of various parameters on the skin friction coefficient and Nusselt number coefficient of base GO–EG/GO–Ware displayed and discussed.


2020 ◽  
Vol 9 (4) ◽  
pp. 362-374
Author(s):  
J. C. Umavathi ◽  
Ali J. Chamkha

Nanotechnology has infiltrated into duct design in parallel with many other fields of mechanical, medical and energy engineering. Motivated by the excellent potential of nanofluids, a subset of materials engineered at the nanoscale, in the present work, a new mathematical model is developed for natural convection in a vertical duct containing nanofluid. Numerical scrutiny for the double-diffusive free and forced convection within a duct encumbered with nanofluid is performed. Buongiorno’s model is deployed to define the nanofluid. Robin boundary conditions are used to define the surface boundary conditions. Thermal and concentration equations envisage the viscous, Brownian motion, thermosphores of the nanofluid, Soret and Dufour effects. Using the Boussi-nesq approximation the solutal buoyancy effect as a result of gradients in concentration are incorporated. The conservation equations which are nonlinear are numerically estimated using fourth order Runge-Kutta methodology and analytically ratifying regular perturbation scheme. The mass, heat, nanoparticle concentration and species concentration fields on eight dimensionless physical parameters such as thermal and mass Grashof numbers, Brownian motion parameter, thermal parameter, Prandtl number, Eckert number, Schmidt parameter, and Soret parameter are calculated. The impact of these parameters are outlined pictorially. The velocity and temperature fields are boosted with the thermal Grashof number. The Soret and the Schemidt parameters reduces the nanoparticle volume fraction but it heightens the momentum, temperature and concentration. At the cold wall thermal and concentration Grashof numbers reduces the Nusselt values but they increase the Nusselt values at the hot wall. The reversal consequence was attained at the hot plate. The perturbation and Runge-Kutta solutions are equal in the nonappearance of Prandtl number. The (E. Zanchini, Int. J. Heat Mass Transfer 41, 3949 (1998)). results are restored for the regular fluid. The heat transfer rate is high for nanofluid when matched with regular fluid.


Author(s):  
Ghulam Rasool ◽  
Anum Shafiq ◽  
Yu-Ming Chu ◽  
Muhammad Shoaib Bhutta ◽  
Amjad Ali

Introduction: In this article Optimal Homotopy analysis method (oHAM) is used for exploration of the features of Cattaneo-Christov model in viscous and chemically reactive nanofluid flow through a porous medium with stretching velocity at the solid/sheet surface and free stream velocity at the free surface. Methods: The two important aspects, Brownian motion and Thermophoresis are considered. Thermal radiation is also included in present model. Based on the heat and mass flux, the Cattaneo-Christov model is implemented on the Temperature and Concentration distributions. The governing Partial Differential Equations (PDEs) are converted into Ordinary Differential Equations (ODEs) using similarity transformations. The results are achieved using the optimal homotopy analysis method (oHAM). The optimal convergence and residual errors have been calculated to preserve the validity of the model. Results: The results are plotted graphically to see the variations in three main profiles i.e. momentum, temperature and concentration profile. Conclusion: The outcomes indicate that skin friction enhances due to implementation of Darcy medium. It is also noted that the relaxation time parameter results in enhancement of the temperature distribution. Thermal radiation enhances the temperature distribution and so is the case with skin friction.


2010 ◽  
Vol 88 (12) ◽  
pp. 911-917 ◽  
Author(s):  
T. Hayat ◽  
M. Nawaz ◽  
S. Asghar ◽  
Awatif A. Hendi

This study explores the flow of a second-grade fluid in divergent–convergent channel. The problem formulation is first developed, and then the corresponding nonlinear problem is solved by homotopy analysis method (HAM). The effects of different physical parameters on the velocity profile are shown. The numerical values of the skin friction coefficient for different values of parameters are tabulated.


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