The centerline pressure and cavity shape of horizontal plane choked vapor jets with low condensation potential

A study of plane, underexpanded, condensing vapor jets was undertaken using flash photography and a ventilated pressure probe. This study examined hor izontal jets with much lower condensation driving potentials than have been previously studied. Photographic measurements of jet expansion angles, spr ead angles, cavity lengths, and cavity shapes were recorded and compared wi th numerical predictions using a parabolic, locally homogeneous flow model that had been modified to incorporate entrainment and condensation effects. When rendered dimensionless by the nozzle width rather than diameter, the plane condensation length agreed well with previously published round jet c orrelations for higher condensation driving potentials. At lower condensati on driving potentials, the jets began to disperse, showing behavior similar to submerged air and energetic reacting vapor jets. Numerical predictions of condensation length were in good agreement over the entire range of meas urement. Numerical predictions of vapor cavity shape were in reasonable agr eement at higher condensation potentials but underpredicted the width of th e vapor cavity at lower potentials. Pressure measurements showed the existe nce of periodic expansian/compression cells associated with under expanded noncondensing gas jets. When these measurements were compared with similar measurements of air jets into quiescent wafer baths, the lengths of the ini tial steam vapor expansian/compression cells were substantially greater tha n those of the air jets, and the degree of pressure recovery over the cell length was substantially less.