In the context of sustainable manufacturing, an efficient coolant delivery system is essential to minimize tool wear while maintaining the machined surface quality. The cooling performance, however, strongly varies depending on operating parameters and tool-workpiece interaction. The current study addressed this issue and developed a Computational Fluid Dynamics (CFD) model to evaluate coolant flow behavior in internally cooled milling. The simulations from the model were tested against surrogated experimental rigs, and the comparison showed good agreement. The analysis was based on the Design of Experiments (DOE) framework, particularly Central Composite Design (CCD), where the influence of three factors, namely workpiece geometry (flat vs.