Air-Assist Atomizers for Fuel-Flexible Gas Turbine Combustors and Augmentors

ABSTRACT:Jet-in-crossflow fuel injectors are commonly used to fuel gas turbine main combustors and augmentors. The performance of this type of atomizer is sensitive to the engine operating condition, so that fuel placement can vary over the flight envelope. This can lead to suboptimal fueling and combustion stability issues. Similarly, changes in fuel physical properties impact jet penetration and breakup characteristics. The emergence of alternative jet fuels, which can have significantly different physical properties, may exacerbate fuel placement issues. We propose to develop a new fuel injector technology that has improved atomization performance and more optimal fuel placement than existing atomizers. Our approach utilizes air-assist to influence the atomization process. This approach does not involve radical changes to fuel systems, and is therefore well suited for low-cost retrofit on existing engine platforms. Improving atomization performance will enhance both overall combustion stability, and enable the use of alternative fuels with different physical properties without encountering combustion stability issues. In Phase I, we will design and fabricate prototypes and demonstrate their performance relative to jet-in-crossflow injectors in non-reacting flows. In Phase II, we will demonstrate our most promising atomizer designs in an augmentor rig with optical access for direct viewing of fuel placement.BENEFIT:Technology developed under this program will be in the form of new atomizers for gas turbine combustors (both main combustors and augmentors). These atomizers will enhance the combustion stability (static and dynamic) and performance of military jets running JP-8. Furthermore, it will also help enable the transition and certification of alternative fuels. This injector technology will be generally applicable as a replacement technology for systems using jet-in-crossflow fuel injectors including commercial aircraft engines.