Additively Manufactured, Structurally-Integrated, Passive Two-Phase Heat Sink for Electrified Aircraft Propulsion Systems

In an effort provide significant improvements in aircraft fuel/energy economy and emissions, turbo-, hybrid, and fully electric aircraft are being developed to utilize high-efficiency electric propulsion systems (EAPs). To enable these systems, thermal management systems (TMS) are needed which can be scaled to the power ranges required while providing the efficiency and power density that makes these technologies compelling. ThermAvant Technologies, LLC proposes a novel TMS based on the companyrsquo;s flagship technology: structurally embedded oscillating heat pipes (OHPs). The OHP is a passive two-phase heat transfer device that relies on concentrated heat loads to passively drive a working fluid through a high-density array of microchannels, which are ideal for embedding within thin structures such as a structural skin. Without the need for the wick structures of their conventional predecessor heat pipes, OHPs are especially well suited for integration into materials within which it is difficult to construct traditional heat pipes. In addition to the absence of a wick structure, the OHPrsquo;s unique I-beam architecture (formed by the walls between the microchannels) enables the structure to be multifunctional and serve as a structural member with integrated passive thermal management. Furthermore, through the use of additive manufacturing technology, these devices can be deeply integrated within the structure of EAP systems. These high-conductance, embedded devices will provide significant improvements to power density by both decreasing thermal impedance and reducing mass, and provide additional design freedom for the layout of heat generating components within the EAP system while still providing improved thermal performance. To provide further performance optimization under both transient and steady-state conditions, energy storage devices will be evaluated to independently optimize the conductive and capacitive properties of the heat sink.