Rigid, Sectored-Cylinder, Composite-Sandwich Cofferdam

Pulse detonation engines (PDE) are a revolutionary approach to airbreathing propulsion and have the potential to increase range and thrust. Demonstrating rapid deflagration-to-detonation in a PDE combustor using storable, liquid hydrocarbon fuels isessential to their successful development. Unfortunately, liquid fuels require atomization, which introduces the challenge of detonating a liquid droplet spray. Recent research shows that droplet Sauter-mean diameters of less than 3 mm may be required.New atomization technologies will be required to produce these small droplets, as current liquid atomization techniques do not meet all Navy requirements (droplet size, high temperature operability, low pressure drop, high speed on-off pulsing withzero-drip closure and high flow rate). TDA Research, (TDA) teamed with the University of Colorado-Boulder, proposes a novel high-speed, addressable atomization technology to meet these requirements. Monodisperse droplets with a Sauter-mean diameter lessthan 10 mm will be produced at rates up to 100 kHz with very little pressure drop. The atomizer will be designed to operate with kerosene fuels in the high temperature and pressure environment characteristic of PDEs. Phase I experiments and detaileddesign of a liquid-fueled atomizer will lead to prototype construction and evaluation in Phase II.We anticipate that the atomizer developed by this research will be applicable in a wide range of propulsion and power generation applications includingaircraft and stationary gas turbine engines, ramjets, and liquid fueled rockets. Modern high performance liquid-fueled combustors typically operate at very high energy densities requiring that the fuel be rapidly atomized, evaporated and mixed with theoxidizer. Special attention should also be paid to avoiding combustion instabilities that can impair performance and/or damage hardware. For stationary power generation applications, environmental concerns make prevaporized/premixed operation attractive,but it is again susceptible to combustion instability. The availability of inexpensive, robust injectors that can be modulated at high frequencies will open the door for practical active combustion control. In addition, diesel and gasoline directinjection are potential automotive applications with about the same operational frequency as the PDE. Lastly, agricultural markets exist for fertilizer and pesticide dispersion and cooling of livestock.