Irreversibility scrutiny of SWCNT and MWCNT nanofluid convective flow using Darcy-Forchheimer rule in an upright microchannel with variable thermal conductivity and Brownian motion and thermophoresis

Abstract

Carbon nanotubes are used to attain greater thermal transfer rates in a various of enormous applications in the field of microsystem, emission, conductive polymers, fibers, and fabrics. Hence the aim of this article is to explore the entropy generation analysis of single wall carbon nanotubes and multiwall carbon nanotubes flow in an upright micro channel with variable thermal conductivity. The exponential heat source and non-linear thermal radiation were considered. The micro channel retains the no slip and convective boundary conditions. The Buongiorno model was used in this study, which emphasizes the light on Brownian motion and thermophoresis phenomena that occur during the fluid flow. Darcy- Forchheimer model is also taken into account. The governing equation numerically solved by employing Runge-Kutta Fehlberg's fourth-fifth order. The repercussion of this study upholds that the inflates of variable thermal conductivity magnify the thermal field. Entropy production inflates at right wall of the channel with augmented Brownian parameter and exhibits exactly opposite behavior at left wall of the channel. One of the important tasks of the investigation was to compare SWCNT and MWCNT. The findings confirmed that multiwall carbon nanotubes exhibit more magnificent heat and mass transfer than single wall carbon nanotubes.

KEYWORDS:

• Buongiorno model
• Darcy-Forchheimer rule
• irreversibility analysis
• carbon nanotubes
• variable thermal conductivity
• non-linear radiation

Acknowledgement

The authors thank the Department of Science and Technology, Government of India for their support under DST-FIST programme for HEIs. (grant number SR/FST/MS-I/2018/23(C)).

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author M.L. Keerthi is thankful to the University Grants Commission, New Delhi, India (Student ID: 191620111468)/ (CSIR-UGC NET DEC. 2019) for financial support in the form of UGC-Junior Research Fellowship.