Micro-Propulsion Systems Hybrid Combustor/Solid Oxide Fuel Cell Power System for Micro Air Vehicles
The overall objective of this work is to develop a compact, liquid hydrocarbon-based power system that can be used as a hybrid propulsion system for a small unmanned air vehicle (UAV) that is quiet, highly efficient, and capable of operating on tactical fuels like JP8. The proposed system illustrated in Figure 1 consists of a partial oxidation reactor, solid oxide fuel cell, and micro-combustor. The flow path through the device is designed so that heat release in the combustor provides the reactant pre-heating necessary to operate the reformer and solid oxide fuel cell. However, it offers several additional benefits. First, it enables recovery of chemical potential energy that would otherwise be lost in the exhaust. Second, it allows one to adjust the mode of power output from mostly heat (that is convertible to mechanical thrust) for takeoff and maneuvering to mostly electrical output for cruise when the vehicle’s sensing and transmitting systems require more power. The approach is to develop experimentally validated thermodynamic models for the individual system components, use these component models to develop a thermodynamic model of the system, and then to design and construct a prototype.