Numerical investigation of entropy production in SWCNT/H2O nanofluid flowing through inwardly corrugated tube in turbulent flow regime

This work numerically investigates the entropy production rate in single-walled carbon nanotubes (SWCNTs)/H2O nanofluid flowing through an inwardly corrugated pipe in turbulent flow regime. The governing equations (continuity, momentum, energy, rate of turbulent production and specific turbulent dissipation) were solved using SSTk-ω\documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$\left( {{\text{SST}}\,k - \omega } \right)$$\end{document} model. Parametric study was carried out on the effect of Reynolds number (5000–40,000), nanoparticle concentration (0–0.25%) and dimensionless amplitude (e/d = 0, 0.08, 0.12 and 0.16) on entropy production rate and Bejan number. The results show the field profile of the Bejan number and the thermal and viscous entropy production rate for various amplitudes of the corrugated pipe. The study also observed that an increment in concentration of SWCNT–water nanofluid and dimensionless amplitude of the corrugation reduced the thermal entropy production but enhanced viscous entropy production. For instance, the change in thermal and viscous entropy production rate at Re = 20,000 and vol = 0.25% between corrugation amplitude 0.12 and 0.16 was − 1.27% and 53.15%, respectively.