A NEW UNSTEADY MIXING MODEL TO PREDICT NOX PRODUCTION DURINGRAPID MIXING IN A DUAL-STAGE COMBUSTOR

AN ADVANCED GAS TURBINE ENGINE TO POWER SUPERSONIC TRANSPORTAIRCRAFT IS CURRENTLY UNDER STUDY. IN ADDITION TO HIGH COMBUSTION-EFFICIENCY REQUIREMENTS, ENVIRONMENTAL CONCERNS HAVE PLACED STRINGENT RESTRICTIONS ON THE POLLUTANT EMISSIONS FROM THESE ENGINES. A COMBUSTOR DESIGN WITH THE POTENTIAL FOR MINIMIZING POLLUTANTS SUCH AS NOX EMMISSIONS IS UNDERGOING EXPERIMENTAL EVALUATION. A MAJOR TECHNICAL ISSUE IN THE DESIGN OF THIS COMBUSTOR IS HOW TO RAPIDLY MIX THE HOT, FUEL-RICH PRIMARY-ZONE PRODUCT WITH THE SECONDARY DILUENT AIR TO OBTAIN A FUEL-LEAN MIXTURE FOR COMBUSTION IN THE SECONDARY STAGE. NUMERICAL PREDICTIONS USING STEADY-STATE METHODS CANNOT ACCOUNT FOR THE UNSTEADY PHENOMENA IN THE MIXING REGION. THEREFORE, THIS PROJECT ADDRESSES A NOVEL UNSTEADY MIXING MODEL THAT CAN BE USED TO EVALUATE MIXING AND COMBUSTION, INCLUDING NO PRODUCTION WITHIN THE MIXING REGION. THIS MODEL WILL BE DEVELOPED FOR USE IN CONJUNCTION WITH STEADY-STATE PREDICTION METHODS AND THUS WILL HAVE THE POTENTIAL FOR PROVIDING AN IMPROVED ENGINEERING DESIGN ANALYSIS TOOL. THE CAPABILITY OF THIS MODEL WILL BE DEMONSTRATED IN PHASE I WITH THE EVENTUAL OBJECTIVE OF COUPLING THE MODEL TO A STEADY-STATE SOLVER IN PHASE II. AN ADVANCED GAS TURBINE ENGINE TO POWER SUPERSONIC TRANSPORTAIRCRAFT IS CURRENTLY UNDER STUDY. IN ADDITION TO HIGH COMBUSTION-EFFICIENCY REQUIREMENTS, ENVIRONMENTAL CONCERNS HAVE PLACED STRINGENT RESTRICTIONS ON THE POLLUTANT EMISSIONS FROM THESE ENGINES. A COMBUSTOR DESIGN WITH THE POTENTIAL FOR MINIMIZING POLLUTANTS SUCH AS NOX EMMISSIONS IS UNDERGOING EXPERIMENTAL EVALUATION. A MAJOR TECHNICAL ISSUE IN THE DESIGN OF THIS COMBUSTOR IS HOW TO RAPIDLY MIX THE HOT, FUEL-RICH PRIMARY-ZONE PRODUCT WITH THE SECONDARY DILUENT AIR TO OBTAIN A FUEL-LEAN MIXTURE FOR COMBUSTION IN THE SECONDARY STAGE. NUMERICAL PREDICTIONS USING STEADY-STATE METHODS CANNOT ACCOUNT FOR THE UNSTEADY PHENOMENA IN THE MIXING REGION. THEREFORE, THIS PROJECT ADDRESSES A NOVEL UNSTEADY MIXING MODEL THAT CAN BE USED TO EVALUATE MIXING AND COMBUSTION, INCLUDING NO PRODUCTION WITHIN THE MIXING REGION. THIS MODEL WILL BE DEVELOPED FOR USE IN CONJUNCTION WITH STEADY-STATE PREDICTION METHODS AND THUS WILL HAVE THE POTENTIAL FOR PROVIDING AN IMPROVED ENGINEERING DESIGN ANALYSIS TOOL. THE CAPABILITY OF THIS MODEL WILL BE DEMONSTRATED IN PHASE I WITH THE EVENTUAL OBJECTIVE OF COUPLING THE MODEL TO A STEADY-STATE SOLVER IN PHASE II.