The rapid advancement of Urban Air Mobility (UAM) in the 21st century has led to an increasing demand for efficient and compact thermal management systems to support high power electric vertical take-off-landing (eVTOL) vehicles. This paper presents a novel, high-performance thermal solution, leveraging bi-modal capillary wick structures fabricated through an innovative high voltage Press Sinter Method (PSM) which is critical to advancing the UAM program. These structures are designed to meet the high-power demands of the eVTOL propulsion system by enhancing two-phase heat transfer in heat pipes, which is a key component for managing the thermal loads of the electrified propulsion systems operating in megawatt power levels, improving heat dissipation and cooling efficiency. The bi-modal capillary wick structures have been engineered with controlled porosity and permeability, allowing for superior heat dissipation through enhanced liquid flow, with thermal conductivities hundred times greater than conventional copper heat pipes as discussed in prior literature. The introduction of these structures within the heat pipes ensures a steady and effective cooling of electric motors and associated electronics in eVTOL applications. The wick structure not only reduces thermal resistance in the electric motors, batteries, and electronics, but also addresses the critical heat loads that arise in high power applications. The application of high voltage PSM accelerates the manufacturing process but reduces the manufacturing time by a factor of ten compared to conventional methods, enabling rapid prototyping and flexible design customization for diverse geometries and functional requirements. The research greatly contributes to NASA’s Revolutionary Vertical Lift Technology initiative while exploring the potential for reducing emissions and increasing efficiency in eVTOL propulsion systems, and providing a scalable, low-cost manufacturing solution. Through the integration of advanced materials and additive manufacturing techniques, the research lays the foundation for more efficient, sustainable urban air transportation with emission reducing enhanced thermal management propulsion performance. The findings of this study will have much broader implications for the design of future electric propulsion systems, with the application of cutting-edge manufacturing methodologies in the aviation and transportation industry, and by building upon this foundational work through focusing on the systematic exploration of process variables using a Design of Experiments (DOE) framework. The primary aim is to quantify the sensitivity of porosity and sintering retention outcomes to input conditions, paving the way for more controlled and reproducible wick manufacturing.
Khan et al. (Fri,) studied this question.