Novel Tools for Augmentor Ignition Modeling and Analysis

Reliable ignition is critical to the operational performance of augmented military jet engines. Augmentors must reliably ignite when thrust is needed or the system (and pilot) safety could be compromised. Augmentor ignition is particularly challenging because the igniter must function over a range of operating conditions. In particular, high-altitude, low-pressure conditions are known to confound ignition performance. Augmentor ignition is truly a multi-scale/multi-physics problem, involving electro-magnetism, chemical kinetics, heat transfer, fluid flow, and flame propagation. In this research program, we propose to develop a series of tools that can be used to study the critical processes of the overall ignition process. These include: spark discharge, kernel ignition, and propagation. The ultimate objective of this program will be to exploit these tools to design improved ignition systems for augmentors. In Phase I, we will experimentally characterize the delivered energy of an existing augmentor ignition system. We will then develop a multi-physics simulation tool to reproduce the delivered energy behavior of this igniter, and use the delivered energy data to characterize the ignition performance of the igniter at reduced pressures. In Phase II, we will extend tool development and design and build and test an improved ignition system for augmentors. BENEFIT: Technology derived from this research program will lead to the development of improved ignition systems for augmentors. This technology will enhance the performance and operational reliability of augmented jet engines. Ignition systems are particularly well suited for retro-fit, and could be used for future and legacy systems. In the commercial sector, technology developed under this research program could be applied to any combustion system involving spark ignition, most notably internal combustion engines.