Abstract: This paper presents a numerical analysis of three-dimensional convection flow and heat transfer in a copper–water nanofluid, incorporating key thermal effects relevant to modern engineering applications. The model accounts for thermal radiation, viscous dissipation, Joule heating, and spatially dependent internal heat generation. Similarity transformations reduce the governing equations to a system of nonlinear ordinary differential equations, solved using the Runge-Kutta-Fehlberg (RKF) method. Results show that electromagnetic forces combined with localized heat sources significantly elevate temperature distribution and thermal boundary layer thickness. The copper–water nanofluid exhibits superior heat transfer performance due to its high thermal conductivity.

Keywords: Copper–water nanofluid; Mixed convection; Thermal radiation; Viscous dissipation; Joule heating; Slip flow; Exponential heat source.

VOLUME 9 ISSUE 12 2025: 52 – 80