TRANSPORT OF EXHAUST PRODUCTS IN THE NEAR TRAIL OF A JET ENGINE UNDERATMOSPHERIC CONDITIONS

The transport of exhaust effluents and the possibility of water ice co ntrail formation axe investigated under the specific fluid dynamical c onditions in the near exhaust trail of a subsonic jet aircraft at crui se altitude. By means of a computational model describing the two-dime nsional turbulent mixing of a single jet of hot exhaust gas with the a tmosphere, representative results are discussed on the temperature and saturation ratio evolutions of air parcels in the jet flow field as w ell as on radial distributions of exhaust effluents undergoing chemica l reactions behind the nozzle exit with prescribed, typical net reacti on rates. The results underline the importance of a simultaneous treat ment of spatially resolved jet expansion together with microphysical a nd chemical processes, because this coupling leads to distinct concent ration patterns for various classes of chemical reactants and is essen tial for the detailed prediction of contrails.