High Fuel-Air Ratio (FAR) Combustor Modeling

"Advanced mission requirements for both military and civilian aircraft demand greater engine efficiency and increased thrust-to-weight ratios. These requirements have driven aircraft engine designers to increased pressure ratios and higher totaltemperatures for next generation engines. This increased performance relies, in part, on an increase in fuel-air ratio (FAR). However, as overall FARs reach levels of 0.040, some regions of the combustors will be operating at rich local fuel-air ratios.These regions can lead to burning in the turbine or along the combustor walls where cooling air is available. Since mixing and kinetics control these rich zones, current assessment tools that rely on equilibrium assumptions are not adequate for evaluatingthe performance of high FAR engines. Thus, the need exists for new kinetics-based modeling tools to assist engine builders in the design and development of high FAR engines. These tools must enable designers to make reasonable predictions of the effectof fuel-air ratio on temperature and species at the combustor exit and at other boundary areas of the combustors such as along film-cooled walls. Combustion Science & Engineering, Inc. proposes to develop a flexible computational tool based on chemicalreactor modeling for the initial stages of gas turbine combustor design. The chemical reactor modeling (CRM) tool to be developed will provide detailed information about the combustion chemist