Analysis and Comparison of Three Alternate Direct Liquid Cooling Concepts for Segmented Axial Flux Machines

Effective thermal management systems (TMS) are essential for achieving high current and power densities in electric machines. This study presents a comparative evaluation of three direct liquid cooling (DLC) strategies for a yokeless and segmented armature (YASA) axial flux machine (AFM): a flooded stator (FS), an end-winding jet (EWJ) system, and modular encased segments (MES). Using steady-state thermal simulations, the configurations are assessed in terms of heat transfer, required pumping power, and temperature uniformity. Results highlight key trade-offs between performance and design complexity, with the MES configuration demonstrating superior thermal efficiency, requiring 39% less flow than the FS and 60% less than the EWJ.