Enhancing Engine Operating Envelope by Ignition and Lean Blowout Modeling and Simulation

Combustion Science & Engineering, Inc. (CSE) proposes to develop an advanced modeling tool that incorporates the abilities of CFD to properly predict flow field variables with the ability to consider complicated chemical kinetics through the use ofchemical reactor modeling. This tool will be capable of predicting the ignition, relight, and lean blowout behavior of aircraft gas turbine combustor designs. Previous research has shown that the complex chemical processes involved in ignition andblowout could not be adequately represented by a single global reaction rate. Hence, analytical techniques that allow for the use of detailed chemical kinetics must be used for predicting events such as ignition, relight, or lean blowout. CSE hasdeveloped techniques that combine the use of CFD with chemical reactor modeling to predict the flameholding or blowout potential of stagnation or recirculation zones in combustors operating using lean, premixed natural gas / air mixtures. Blowout ispredicted incorporating the important fluid mechanic parameters of the potential flameholding region (determined from CFD) in PSR codes, which allow for the consideration of complex kinetics. This work serves as the basis for the proposed modeling tool.These techniques must be refined and extended for use in aircraft gas turbine engines. An important product from this project will be the development of an automated algorithm for predicting ignition and flameholding potential in combustors. Thisproduct will give the design engineer much more freedom to test new combustor designs operating at wider range of pressures, temperature and fuel / air mixtures. The market for this product will include gas turbine designers and manufacturers for bothmilitary and civilian aircraft. The use of this tool will significantly reduce development costs by eliminating some design iterations and hardware testing, which is quite expensive and time-consuming. This tool will also be useful for engineersdeveloping stationary gas turbines for power generation.