Electrostatically Actuated Fuel Atomizer Design for the Pulse Detonation Engine

The pulse detonation engine (PDE) 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 droplet spray. Recent research (1-2) shows that droplet Sauter-mean diameters as small as 3 µm may be required. New atomization technologies will be required to produce these small droplets with low supply pressure. The atomizer must also deliver high flow rate, be operable to high temperature, and have high-speed on/off pulsing capability with zero- drip closure. TDA Research, teamed with the University of Colorado-Boulder is developing technology for a novel high-speed atomizer based on electrostatic inkjet technology. Nearly monodisperse droplets with a Sauter-mean diameter of less than 10 µm should be produced at rates up to 100 kHz with very little pressure drop. Inkjets use individual nozzle addressing, which should not be required for the PDE application. Still, the desired pulse injection cycle time (near 100 Hz) to optimize the engine specific impulse can be precisely and independently controlled. Analyses indicates that atomizer development will be required to achieve the high mass flow rate using kerosene-type fuels in the thermal and dynamic pressure environment characteristic of PDEs. NOMENCLATURE