The project aimed to define an effective procedure to determine pollutant emission from helicopter engines during different flying conditions. The basic strategy was to couple detailed kinetics, needed to determine those components which are present in a low or very low concentration, with detailed fluidynamics necessary to describe in an accurate way the thermal and fluid flow fields, which control the pollutant formation/reduction. After an accurate analysis of the state of the art, starting point of the activity was the definition of the helicopter surrogate fuel and the development, tuning and validation of their combustion kinetics. The resulting detailed mechanism was the starting point for the construction of an optimised global few step kinetic mechanism to be used in CFD computations.

The CFD simulations were based on the global mechanism, the combustor geometry and flying conditions. The temperature and flow field coming from CFD and the detailed kinetic scheme were the input for the postprocessing activity for the pollutant emission estimation. Effective and parallel numerical algorithms increase the performances of such a time-consuming activity. Several CFD and postprocessing computations in the different flying allow to compare with experimental results. In this procedure some iterations could be necessary. The fluidynamic results can show the need of detailed and/or global kinetic refinements. As a consequence, the output of CFD computations can impact on detailed kinetic scheme development and validation and/or to the global few step mechanism. Again, over or under-estimations of the emissions from postprocessor could require revising either the kinetics or the CFD.