年間 6 号発行
ISSN 印刷: 2150-766X
ISSN オンライン: 2150-7678
Indexed in
EXPERIMENTAL STUDY OF SUBCRITICAL TO SUPERCRITICAL JET MIXING
要約
Liquid jet injection into a quiescent gaseous environment has been studied experimentally and analytically covering subcritical to supercritical conditions. The focus was placed on influences the surrounding gas pressure and temperature have on the jet break-up. Subcritical, transcritical and supercritical jet break-up mechanisms were observed. Under the subcritical conditions first and second wind-induced break-up regimes were observed; the surrounding gas inertia and surface tension forces were the controlling factors in this case. Decreasing surface tension influenced the jet surface behavior under transcritical conditions: ligament formation was significantly reduced under these conditions with only occasional drop formation. Further increasing the pressure and temperature led to supercritical break-up modes. This manifested through a smoothening of the liquid-gas interface. Ligament formation was not observed under supercritical conditions; this indicated that surface tension did not play any role in the supercritical jet break-up. Despite the apparent absence of the surface tension the density gradients values observed under supercritical conditions were comparable to those observed under subcritical conditions. The experimental technique, using planar laser induced fluorescence, revealed important core jet structures undetected previously. A linear jet stability analysis was, then, performed to gain physical insight into the jet break-up mechanisms. The results showed good correlation with experimental results under subcritical mixing but failed to predict the transcritical and supercritical regimes.