Turbulent air-steam jets with a condensed dispersed phase: Theory, experiment, numerical modeling

Development of a condensed dispersed phase (CDP) in turbulent vapor-air jets in the laboratory and in aircraft engine jets is investigated. Specific features of this condensation process are considered: the overall effect of turbulent mixing between jet and ambient medium on formation of steam supersaturation conditions; development of a “visible” condensation wake at some distance behind the aircraft; the possibility of condensation control by variations of certain parameters at the nozzle exit and in the surrounding space; simultaneous homogeneous and heterogeneous condensation; increased nucleation rates due to turbulent pulsations. A new effect—condensation augmentation and appearance of stratified condensation patterns due to introducing corona ions into the vapor-air jet—is studied. CDP pulsations due to flow turbulence and the corona discharge are investigated. Large differences between CDP and passive additive pulsation intensities due to the droplet inertia are observed and analyzed. The existence of correlations between electric, optical and acoustic signals is detected and analyzed. Numerical modeling of CDP formation in turbulent vapor-air submerged/co-flowing jets is discussed. The general model includes turbulent jet equations; kinetic correlations (approximated by moment equations); an averaging method for source terms in turbulent flow. The problems of formation and growth of water, ice and sulfuric acid aerosols due to the interactions of aircraft engine jets with the atmosphere are described.