FUEL DUMP IMPACT ASSESSMENT MODEL

THE OBJECTIVE OF THIS PROGRAM IS THE DEVELOPMENT OF A PROTOTYPE, MICROCOMPUTER BASED MODEL THAT WILL COMPUTE THE QUANTITIES, LOCATIONS, AND DISTRIBUTIONS OF FUEL JETTISONED BY AIRCRAFT THAT REACHES THE GROUND. THE APPROACH PROPOSED CONSISTS OF A DETAILED, MECHANISTIC AND PHYSICALLY REALISTIC MODEL. IT EMPLOYS ELEMENTS OF SPRAY COMBUSTION MODELING WHEREBY DROPLETS ARE DIVIDED INTO REPRESENTATIVE GROUPS AND THESE GROUPS ARE TRACKED AS THEY ARE HEATED, EVAPORATE, BREAKUP, AND MOVE UNDER THE INFLUENCE OF GRAVITY AND LOCAL WINDS. THIS IS A WELL ESTABLISHED AND SUCCESSFUL APPROACH THAT CAN BE EASILY ADAPTED FOR FUEL DROPLETS FALLING THROUGH THE ATMOSPHERE. IN ORDER TO KEEP THE MODEL RUN TIME SHORT ENOUGH TO MAKE THIS APPROACH FEASIBLE FOR A MICROCOMPUTER, ONLY A SMALL PORTION OF THE JETTISONED FUEL WILL BE MODELED IN DETAIL. THE FINAL DISPOSITION OF THE REMAINDER OF THE JETTISONED FUEL CAN BE INFERRED FROM THE TRAJECTORIES AND IMPACT POINTS OF THE FUEL THAT IS TRACKED IN DETAIL. THIS IS MADE POSSIBLE BY DIVIDING THE FLIGHT PATH DURING DUMPING INTO SEGMENTS DURING WHICH THE FORCES ACTING ON THE FUEL DROPLETS DO NOT VARY WITH DUMP LOCATION. ONE OF THE MAJOR OBSTACLES TO THIS APPROACH (OR ANY OTHER REALISTIC APPROACH) TO THIS MODEL IS THE INABILITY TO PREDICT THE INITIAL DROPLET SIZE DISTRIBUTION. WHILE SOME EXCELLENT DATA IS AVAILABLE, IT IS LIMITED TO ONLY A FEW CONDITIONS OF INTEREST, AND THERE IS LITTLE BASIS FOR EXTRAPOLATING THIS DATA TO OTHER AIRCRAFT, FLIGHT PROFILES, FUELS, ETC. THE SOLUTION TO THIS PROBLEM PROPOSED HEREIN IS TO EMPLOY BASIC RESEARCH ATOMIZATION DATA TO PROVIDE BEST ESTIMATES OF THE EFFECT OF UNTESTED VARIABLES ON THE INITIAL DROPLET SIZE DISTRIBUTION.