On Darcy-Forchheimer flow of carbon nanotubes due to a rotating disk

AbstractThe current research explores incremental effect of thermal radiation on heat transfer improvement corresponds to Darcy–Forchheimer (DF) flow of carbon nanotubes along a stretched rotating surface using RSM. Casson carbon nanotubes’ constructed model in boundary layer flow is being investigated with implications of both single-walled CNTs and multi-walled CNTs. Water and Ethylene glycol are considered a basic fluid. The heat transfer rate is scrutinized via convective condition. Outcomes are observed and evaluated for both SWCNTs and MWCNTs. The Runge–Kutta Fehlberg technique of shooting is utilized to numerically solve transformed nonlinear ordinary differential system. The output parameters of interest are presumed to depend on governing input variables. In addition, sensitivity study is incorporated. It is noted that sensitivity of SFC via SWCNT-Water becomes higher by increasing values of permeability number. Additionaly, sensitivity of SFC via SWCNT-water towards the permeability number is higher than the solid volume fraction for medium and higher permeability levels. It is also noted that sensitivity of SFC (SWCNT-Ethylene-glycol) towards volume fraction is higher for increasing permeability as well as inertia coefficient. Additionally, the sensitivity of LNN towards the Solid volume fraction is higher than the radiation and Biot number for all levels of Biot number. The findings will provide initial direction for future device manufacturing.

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Transportation of hybrid nanoparticles in forced convective Darcy-Forchheimer flow by a rotating disk

International Communications in Heat and Mass Transfer ◽

10.1016/j.icheatmasstransfer.2021.105177 ◽

2021 ◽

Vol 122 ◽

pp. 105177 ◽

Cited By ~ 9

Author(s):

M. Ijaz Khan

Keyword(s):

Rotating Disk ◽

Hybrid Nanoparticles ◽

Forchheimer Flow

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Numerical simulation for Darcy-Forchheimer flow of carbon nanotubes due to convectively heated nonlinear curved stretching surface

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-01-2019-0016 ◽

2019 ◽

Vol 29 (9) ◽

pp. 3290-3304 ◽

Cited By ~ 6

Author(s):

Muhammad Ijaz Khan ◽

Khursheed Muhammad ◽

Tasawar Hayat ◽

Shahid Farooq ◽

Ahmed Alsaedi

Keyword(s):

Carbon Nanotubes ◽

Volume Fraction ◽

Continuous Phase ◽

Curved Surface ◽

Content Type ◽

Porosity Parameter ◽

Forchheimer Number ◽

Forchheimer Flow ◽

Walled Cnts ◽

Behavior Index

Purpose This paper aims to discuss the salient aspects of the Darcy–Forchheimer flow of viscous liquid in carbon nanotubes (CNTs). CNTs are considered as nanofluid, and water is taken as the continuous phase liquid. The flow features are discussed via curved surface. Water is taken as the base liquid. Flow is generated via nonlinear stretching. Energy expression is modeled subject to heat generation/absorption. Furthermore, convective conditions are considered at the boundary. The Xue model is used in the mathematical modeling which describes the features of nanomaterials. Both types of CNTs are considered, i.e. single-walled CNTs and multi-walled CNTs. Design/methodology/approach Appropriate transformations are used to convert the flow expressions into dimensionless differential equations. The bvp4c method is used for solution development. Findings Velocity enhances via higher estimations of nanoparticles volume fraction while decays for higher Forchheimer number, curvature parameter, behavior index and porosity parameter. Furthermore, thermal field is an increasing function of nanoparticle volume fraction, behavior index, Forchheimer number and porosity parameter. Originality/value Here, the authors have discussed two-dimensional CNTs-based nanomaterial Darcy–Forchheimer flow of viscous fluid over a curved surface. The authors believe that all the outcomes and numerical techniques are original and have not been published elsewhere.

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Numerical treatment for Darcy–Forchheimer flow of nanofluid due to a rotating disk with convective heat and mass conditions

International Journal of Numerical Methods for Heat &amp Fluid Flow ◽

10.1108/hff-10-2017-0389 ◽

2018 ◽

Vol 28 (11) ◽

pp. 2531-2550 ◽

Cited By ~ 5

Author(s):

T. Hayat ◽

Arsalan Aziz ◽

Taseer Muhammad ◽

A. Alsaedi

Keyword(s):

Biot Number ◽

Design Methodology ◽

Rotating Disk ◽

Random Motion ◽

Shooting Technique ◽

Content Type ◽

Forchheimer Number ◽

Opposite Trend ◽

Lower Temperature ◽

Forchheimer Flow

Purpose The purpose of this study is to examine the Darcy–Forchheimer flow of viscous nanoliquid because of a rotating disk. Thermophoretic diffusion and random motion aspects are retained. Heat and mass transfer features are analyzed through convective conditions. Design/methodology/approach The governing systems are solved numerically by the shooting technique. Findings Higher porosity parameter and Forchheimer number Fr depict similar trend for both velocity profiles f' and g. Both temperature and concentration profiles show increasing behavior for higher Forchheimer number Fr. An increase in Prandtl number Pr corresponds to lower temperature profile, while opposite trend is noticed for thermal Biot number. Larger concentration Biot number exhibits increasing behavior for both concentration and its associated layer thickness. Originality/value To the best of the author’s knowledge, no such consideration has been given in the literature yet.

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N8− Polynitrogen Stabilized on Nitrogen-Doped Carbon Nanotubes as an Efficient Electrocatalyst for Oxygen Reduction Reaction

Catalysts ◽

10.3390/catal10080864 ◽

2020 ◽

Vol 10 (8) ◽

pp. 864 ◽

Cited By ~ 1

Author(s):

Zhenhua Yao ◽

Ruiyang Fan ◽

Wangyang Ji ◽

Tingxuan Yan ◽

Maocong Hu

Keyword(s):

Carbon Nanotubes ◽

Oxygen Reduction Reaction ◽

Oxygen Reduction ◽

Rotating Disk ◽

Reduction Reaction ◽

Rotating Disk Electrode ◽

Nitrogen Doped ◽

Metal Free ◽

Temperature Programmed ◽

Nitrogen Doped Carbon

In this work, non-traditional metal-free polynitrogen chain N8− deposited on a nitrogen-doped carbon nanotubes (PN-NCNT) catalyst was successfully synthesized by a facile cyclic voltammetry (CV) approach, which was further tested in an oxygen reduction reaction (ORR). The formation of PN on NCNT was confirmed by attenuated total reflectance–Fourier transform infrared spectroscopy (ATR-FTIR) and Raman spectroscopy. Partial positive charge of carbon within NCNT facilitated electron transfer and accordingly induced the formation of more PN species compared to CNT substrate as determined by temperature-programmed decomposition (TPD). Rotating disk electrode (RDE) measurements suggested that a higher current density was achieved over PN-NCNT than that on PN-CNT catalyst, which can be attributed to formation of the larger amount of N8− on NCNT. Kinetic study suggested a four-electron pathway mechanism over PN-NCNT. Moreover, it showed long stability and good methanol tolerance, which indicates its great potential application. This work provides insights on designing and synthesizing non-traditional metal-free catalysts for ORR in fuel cells.

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