Practical CFD Models for Predicting Lean Blowout and Ignition in Gas Turbine Combustors

Current steady-state CFD combustion codes cannot predict transient combustion phenomena such as lean blowout (LBO) and ignition in gas turbine combustors. In this SBIR, we propose to develop an innovative analytical capability so that the combustordesigner can address operability issues. The key to predicting LBO/ignition is the use of time-accurate Unsteady Reynolds Averaged Navier Stokes (URANS) or Large Eddy Simulation (LES) analyses, and development/validation of important physical models: 1)atomization/spray models based on first principles, 2) reduced chemistry models that include minor species necessary to predict near extinction reactions, and 3) turbulent-combustion interaction models for highly-strained flames. We will start with ourcurrent URANS/LES software and show the feasibility of predicting LBO in Phase I. LBO of various versions of CFDRC's low emissions fuel injector will be predicted, and compared to experimental measurements. Various physical models will be employed, as wetry to balance fidelity with computational expense. In Phase II, improved spray/atomization models and practical laminar flamelet models based on JP8-air chemistry will be implemented and validated. Ignition models will be implemented that includeionization chemistry and flame kernel growth. The final CFD software will be applied to the Rolls-Royce JSF F136 combustor, including CFDRC's fuel injector being considered as a candidate design. The final products of this SBIR will be validated CFDmodels developed specifically for predicting/analyzing LBO and ignition in advanced military gas turbine combustors such as JSF and VAATE. Combustor designers and Air Force personnel will be able to use the software to address operability issues, thusavoiding extensive rig/engine tests and their associated costs. The CFD models will be implemented and validated in a commercial CFD code, CFD-ACE+, and licensed to interested parties, specifically gas turbine engine companies and fuel nozzle vendors. Inaddition, stand-alone modules for spray and chemistry will be made available for licensing and implementation into other CFD codes.