A MEMS Fuel Atomizer for Advanced Engines

Future aircraft and weapons need highly efficient propulsive power plants to achieve their performance goals. Higher performance engines such as the pulse detonation engine (PDE) are needed. The pulse detonation engine is an exciting airbreathing propulsion cycle with great potential for improved range and thrust. Most research has been performed with gaseous fuels, so demonstrating rapid deflagration-to-detonation using storable, liquid hydrocarbon fuels is essential to successful development and application of this engine. Unfortunately, liquid fuels require atomization unless pre-vaporized, which introduces the challenge of detonating a liquid spray. Recent research shows that droplet Sauter-mean diameters as small as 3 µm may be required for successful detonations. Unfortunately, currently available atomizers produce a droplet distribution that has an unacceptably large number of big droplets (up to 200µm) even though the Sautermean diameter can be as small as 30-40µm. Thus, new atomization technologies are needed to produce these small droplets. Using microelectromechanical (MEMS) technology, atomizers can be built with the micron scale features needed to obtain very fine droplet atomization. In this paper we describe the design, fabrication and packaging challenges encountered in building a MEMS fuel atomizer for use in advanced engines.