A PROBABILITY DENSITY FUNCTION (PDF) METHOD FOR TURBULENT REACTING FLOWS

MODELING METHODS DEVELOPED FOR NON-REACTING TURBULENT FLOWS ARE NOT ABLE TO CAPTURE IMPORTANT INTERACTIONS OF TURBULENCE AND COMBUSTION. AN ALTERNATIVE APPROACH SOLVES AN EQUATION FOR THE JOINT PROBABILITY DENSITY FUNCTION (PDF)OF THE LOCAL VELOCITY AND COMPOSITION, INSTEAD OF SOLVING A SET OF EQUATIONS FOR THEIR FIRST-AND SECOND-ORDER MOMENTS. WHILE PDF METHODS HAVE BEEN PROPOSED IN THE PAST, THEY HAVE ONLY BEEN USED IN CERTAIN SIMPLIFIED SITUATIONS. IN THIS PROJECT, THE COMPANY WILL DEVELOP AN EFFICIENT PDF SOLUTION PROCEDURE FOR GENERAL REACTING FLOWS. IN PHASE I, A STAND-ALONE MODULE WILL BE DEVELOPED USING A LAGRANGLAN MONTE CARLO SOLUTION METHOD. THE MODULE WILL BE VALIDATED BY COMPARISON WITH BENCHMARK DATA. THESE COMPARISONS WILL BE USED TO ASSESS THE FEASIBILITY OF THE PDF METHOD AND TO DETERMINE THE REQUIREMENTS FOR COUPLING THE MODULE WITH A FINITE-VOLUME CFD CODE. IN PHASE II, THE COUPLING WOULD BE PERFORMED AND THE METHODOLOGY EXTENDED TO THREE-DIMENSIONAL FLOWS. THE PDF MODULE AND FINITE VOLUME CODE WOULD BE FULLYDOCUMENTED AND DELIVERED TO NASA AT THE END OF PHASE II. MODELING METHODS DEVELOPED FOR NON-REACTING TURBULENT FLOWS ARE NOT ABLE TO CAPTURE IMPORTANT INTERACTIONS OF TURBULENCE AND COMBUSTION. AN ALTERNATIVE APPROACH SOLVES AN EQUATION FOR THE JOINT PROBABILITY DENSITY FUNCTION (PDF)OF THE LOCAL VELOCITY AND COMPOSITION, INSTEAD OF SOLVING A SET OF EQUATIONS FOR THEIR FIRST-AND SECOND-ORDER MOMENTS. WHILE PDF METHODS HAVE BEEN PROPOSED IN THE PAST, THEY HAVE ONLY BEEN USED IN CERTAIN SIMPLIFIED SITUATIONS. IN THIS PROJECT, THE COMPANY WILL DEVELOP AN EFFICIENT PDF SOLUTION PROCEDURE FOR GENERAL REACTING FLOWS. IN PHASE I, A STAND-ALONE MODULE WILL BE DEVELOPED USING A LAGRANGLAN MONTE CARLO SOLUTION METHOD. THE MODULE WILL BE VALIDATED BY COMPARISON WITH BENCHMARK DATA. THESE COMPARISONS WILL BE USED TO ASSESS THE FEASIBILITY OF THE PDF METHOD AND TO DETERMINE THE REQUIREMENTS FOR COUPLING THE MODULE WITH A FINITE-VOLUME CFD CODE. IN PHASE II, THE COUPLING WOULD BE PERFORMED AND THE METHODOLOGY EXTENDED TO THREE-DIMENSIONAL FLOWS. THE PDF MODULE AND FINITE VOLUME CODE WOULD BE FULLYDOCUMENTED AND DELIVERED TO NASA AT THE END OF PHASE II.