Velocity and Thermal Slip of Hybrid Carbon Nanotubes via Extendable/Shrinkable Cylinder: Heat Transfer Optimization

ABSTRACT The implementation of hybrid carbon nanotubes (CNTs) represents a significant advancement in enhancing heat transfer efficiency compared to conventional fluids. This study investigates the role of hybrid CNTs in stretch/shrink cylindrical frameworks, considering the effects of thermal slip and radiation on velocity. The hybrid nanofluid flow model is formulated using partial differential equations (PDEs) with appropriate boundary conditions (BCs), which are then transformed into ordinary differential equations (ODEs) via similarity solutions and numerically solved using bvp4c in MATLAB. The analysis evaluates the impact of slip, curvature, and radiation on the local Nusselt number and skin friction coefficient, offering deeper insights into the underlying heat transfer mechanisms. The results indicate that hybrid CNTs enhance both skin friction and heat transfer efficiency compared to single‐walled (SWCNT) and multi‐walled (MWCNT) CNTs. Furthermore, response surface methodology (RSM) is employed to establish the relationship between the Nusselt number and governing equation parameters, providing a comprehensive understanding of the parametric influences on heat transfer optimization. These findings underscore the practical significance of hybrid CNTs in improving thermal performance for various engineering applications, such as in polymer extrusion, cooling of flexible materials, micro‐scale heat exchangers, and advanced thermal management systems, where efficient control of heat and fluid flow is crucial.