This paper describes experimental and computational simulation work on the laminar regime of convective heat transfer of Kerosene-based Ferrofluid (KBFF) (1.36% vol. Fe₃O₄) through a partially heated copper enclosure in the presence of non-uniform magnetic field (NUMF) generated by (a single, double, and circular ring) permanent magnet. Using the finite volume method (FVM) and the control volume methodology, the hydrodynamics and thermal behavior of the flow are explored numerically. The magnetic field strength (MFS), velocities and temperature characteristics and distribution, the HTE, and the Nusselt number (Nu) variation concerning the aspect ratio (l/d) are all examined through several of numerical simulations. This computational simulation and experimental studies observe significant augmentation in the heat transfer FF by applying various concerns and size and their orientation of NUMF. The computational simulation data revealed that magnetizing body force (MBF) influences the heat transfer rate, and the productive data confirm that an MF perpendicular to the can improve heat transfer. Based on the results, the Nu can be controlled externally using the MMF with different shapes, orientations, positions, and gradients. The main reason for the enhancement of heat transfer (in terms of Nu) could be caused due to remarkable changes in thermos-physical properties of KBFF under the influence of applied NUMF.