A Study of External Fuel Vaporization

Abstract

A conceptual design study was conducted to devise and evaluate techniques for the external vaporization of fuel for use in an aircraft gas turbine with characteristics similar to the Energy Efficient Engine (E3). A second purpose of the study was to select the most favorable fuel vaporization concept. In the study, three candidate concepts were analyzed from the standpoint of fuel thermal stability, integration of the vaporizer system into the aircraft engine, engine and vaporizer dynamic response, startup and altitude restart, engine performance, control requirements, safety, and maintenance. The results of the study indicate that an external vaporization system can be devised for an E3 -type engine with hardware of reasonable size. The hardware can be packaged without increasing the total engine volume and the system is not unduly complex. The selected concept offers potential gains in engine performance in terms of reduced specific fuel consumption and improved engine thrust/weight ratio. The thrust/weight improvement can be traded against vaporization system weight. However, the vaporizer is subject to fouling with deposits formed at the walls exposed to heated fuel.