CALCULATION OF EXHAUST PLUME STRUCTURE AND EMISSIONS OF THE ER-2 AIRCRAFT IN THE STRATOSPHERE

Calculations are presented for the NASA ER 2 aircraft at high altitude to simulate measurements taken of its own emissions during a wake-cro ssing event. Results are presented for a Mach = 0.71 case in the lower stratosphere with an engine NOX emission index of 4.6 corresponding t o the measured value. A series of codes was used in the analysis to ca lculate the flow field and chemical kinetics, from the engine combusto r out to a distance of about 20.2 km (97 s). Initial plume properties were calculated with a two-dimensional computational fluid dynamics (C FD) code with finite rate chemistry. The results of the plume code ini tialized a three-dimensional parabolized Navier-Stokes (PNS) reacting flow solution, where the plume dynamics interacting with the aircraft wake were calculated out to the region of plume breakup. Results show that the early shape and mixing rate of the engine exhaust plume are d ominated by the presence of the aircraft vortex wake. Model results fo r NOY emissions compare well to in situ measurements taken in the fiel d. Calculated exhaust species evolutions predict several species ratio s in good agreement with field data. The mixing rate of the engine plu me was also predicted to be consistent with dilution measured in the f ield.