Closed-Loop Turbo-Brayton Power System for High-Altitude Aircraft

ABSTRACT: The success of unmanned aerial systems (UASs) has prompted rapid expansion of their capabilities and duties. The sensors and equipment that enable their activities require significant electric power, which can be provided by an auxiliary power unit (APU) that operates independently from the main engine. Conventional APUs are relatively heavy and inefficient for common high-altitude UAS missions because they use ambient air for their working fluid, which has low density at high altitudes. In response, we propose to develop a gas-turbine APU that has a closed-loop configuration with a dense working fluid to make it extremely compact and lightweight. Our team is well suited to succeed because we have a long history developing innovative thermodynamic systems, miniature turbomachines, compact heat exchangers, and advanced combustion systems for challenging applications. During the Phase I project, we will optimize design trades, create a preliminary design, and conduct combustor tests. We will then fabricate and test a prototype system during the Phase II project. BENEFIT: The proposed system will enhance electric power generation for military and civilian applications. Low mass, compact size, and high efficiency make it ideal for aircraft, watercraft, land vehicles, and standalone mobile generators. In addition, high reliability in harsh environments is extremely attractive for military, construction, remote scientific, and off-grid recreational uses.