TECHNOLOGY AREAS: Air Platform, Ground/Sea Vehicles

OBJECTIVE: Develop a lightweight, efficient, high-temperature blower which enables power-dense SOFC power units for long-endurance unmanned vehicle (UV) and munition applications.

DESCRIPTION: In recent years, UVs and weapon system capabilities have required significant adaptation in order to combat an increasingly mobile and elusive adversary. In one particular application, battlefield persistence will be achieved through the use of small (2 to 4 kW), long-endurance unmanned air vehicle (UAV) munitions which are required to stay aloft for 50 hours or more. To achieve these unprecedented endurances, compact SOFC power units are under development wherein system efficiency and power density are balanced such that far greater mission durations are possible compared to conventional reciprocating engines. These systems are currently being designed to operate on military logistic fuels which could include JP-8, JP-10, and desulfurized jet fuels. High-performance fuel processing and power generation subsystems are being developed to meet these requirements. However, these stringent mission requirements also place considerable constraints upon the cathode air blower, including high desired operation temperatures, low power consumption, high throughput air requirements, low weight and volume, and low acoustic operation. This research topic seeks advanced, lightweight, low-volume designs for SOFC cathode air blower/compressors which assist in enabling these long-endurance, high-power dense applications. The blower unit must be able to operate reliably for a minimum 1000 hours while supplying enough air for 2-kW fuel cell operation. Current technology is designed with the following specifications: speed 36,310 rpm, flow and pressure

400 slpm@15kPa, power 215 W, noise 78dBa. Developments should be focused on significant improvements to the parasitic power consumption and/or efficiency. Vibration and acoustic footprint are also primary concerns. System requirements shall be thoroughly analyzed and potential design approaches shall be presented in Phase I.

PHASE I: Conduct a basic trade analysis to down-select competing approaches, and present a detailed design of the approach. Prototype component(s) shall be assembled and tested to demonstrate progression toward meeting performance objectives.

PHASE II: Multiple prototypes of the enhanced design will be assembled and tested to military specifications to verify that they meet weight and performance objectives. Demonstrate that the device is readily manufacturable and project costs of the unit based upon limited (<1000 units) production. Deliverables will include five units which can be integrated into prototype 2-kW SOFC systems.

PHASE III / DUAL USE: Military application: Compact cathode air blowers are essential for achieving high energy and power density, aggressive weight requirements for long-endurance UAV and munition applications. Commercial application: Potential commercial applications could include homeland security and related commercial aerospace applications.

REFERENCES:
1. Fontell, E., Kivisarri, T., Christiansen, N., Hansen, J.-B., and Palsson, J., J. Power Sources, Vol. 131, pp. 49-56, 2004.

2. Fuel Cell Handbook, 7th ed., U.S. Department of Energy, NETL, Prepared under contract DE-AM26-99FT40575, 2004.

3. http://www.netl.doe.gov/seca/.

KEYWORDS: auxiliary power units, APUs, fuel cell powered generators, solid oxide fuel cells, SOFCs, cathode, air blower

TPOC: Michael Rottmayer
Phone: (937) 255-5582
Fax: (937)656-7529
Email: Michael.Rottmayer@wpafb.af.mil