Combustion technology needs for advanced high pressure cycle engines

The challenges in designing high performance aircraft combustion systems have not changed significantly over the years, but the approach has shifted towards a more sophisticated analytical process. Initially an overview of the U.S. Navy's component technology development procedure is presented to show how technology development is still tied into mission requirements. A more technical discussion on combustion technology status and needs will show that the classic impediments that have hampered progress towards near-stoichiometric combustion still exist. Temperature rise, mixing, liner cooling, stability, fuel effects, temperature profile control, and emissions continue to confront the aerodynamic and mechanical designers with a plethora of engineering dilemmas and trade-offs. In addition, new materials such as ceramic matrix composites (CMC) and intermetallics like titanium aluminides (TiAl) are now being incorporated into every advanced design. The process of combustion design has taken on a new meaning over the past several years as three dimensional codes and other advanced design and validation tools have finally changed the approach from a 'cut and burn' technique to a much more analytical process. All of these new aspects are now integral elements of the new equation for advanced combustion design that must be fully understood and utilized. Only then will the operable, high temperature capable combustion systems needed for future military aircraft be developed.