Additively Manufactured Hollow Conductors Integrated With Heat Pipes: Design Tradeoffs and Hardware Demonstration

This article investigates the design of a 250 kW permanent magnet (PM) machine used for aircraft propulsion. The focus is to pursue high specific power (>20 kW/kg), high efficiency (>95%), and low thermal resistance direct-cooling design for the demanding aerospace applications. The proposed key-enabling technology is additively manufactured hollow conductors integrated with heat pipes. Compared to the existing high specific power PM machines for aerospace applications, the proposed design features a much lower speed - 5000 r/min without any torque amplifier, which helps promote the specific power of the overall system. Based on parametric finite-element analysis, tradeoff studies on a variety of winding configurations as well as geometrical parameters have been carried out, highlighting their impact on specific power, winding ac losses, and efficiency. AlSi10Mg coil samples printed by direct metal laser sintering as well as thermal management system have been demonstrated to show the feasibility of the concepts.