Comparative study of SWCNT and MWCNT‐water based non‐axisymmetric Hiemenz stagnation point flow

Abstract This study examines the flow and heat transfer behavior of carbon nanotube (CNT)‐based nanofluids in non‐axisymmetric Hiemenz stagnation‐point flow with single‐walled (SWCNT) and multi‐walled (MWCNT) suspensions in water. CNT nanofluids are of interest due to their superior thermal conductivity, which can significantly improve heat removal and energy transport in advanced engineering systems. Using Xue's model with convective boundary conditions and assuming an undisturbed surface, the governing momentum and energy equations are transformed via similarity transformations into nonlinear ordinary differential equations and solved numerically using the bvp4c method. The effects of viscous dissipation, magnetic field strength, Biot number, stress‐to‐strain‐rate ratio, and surface heat source/sink are analyzed on physical quantities. Results show that incorporating CNTs enhances heat transfer, with MWCNTs providing superior performance over SWCNTs. Stronger convective heating raises the fluid temperature, while the skin friction coefficient increases along the x ‐direction and decreases along the y ‐direction.