Thermal-flow characteristics of an Ellis hybrid nanofluid containing polytetrafluoroethylene-SWCNTs over a stretching/shrinking cylinder with slip effect

Abstract

Hybrid nanofluids containing polytetrafluoroethylene (PTFE) nanoparticles and single-walled carbon nanotubes (SWCNTs) in a H₂O–carboxymethyl cellulose (CMC) medium, using Ellis fluid model, exhibit excellent thermal conductivity and enhanced viscosity. These enhanced properties make them ideal for applications in thermal management systems, medical technologies, tribology, and sustainable energy solutions, highlighting their potential for improved performance and efficiency. This study focuses on analyzing the characteristics of Ellis hybrid nanofluid flow along a stretching or shrinking cylinder, considering the combined impacts of thermal radiation, slip, magnetic field, and suction/blowing. A mathematical model is developed using partial differential equations, which are converted into dimensionless ODEs via similarity transformations. These expressions are then solved numerically with the aid of the bvp4c solver. Graphical representations are utilized to examine the effects of key factors on the velocity and temperature profiles, as well as on the skin friction coefficient and the local Nusselt number. The results show that the curvature parameter, Ellis fluid parameter, and stretching/shrinking parameter enhance flow, while Forchheimer number, porosity, slip, and suction/blowing parameters reduce it. Also, an upsurge in Eckert number, magnetic and radiation parameters enhance temperature, while higher porosity and velocity slip reduce it. Moreover, an increase in curvature parameter reduces the absolute value of the skin friction coefficient, along with rises in velocity slip and shrinking parameters.