Investigation of Breakup of Turbulent Cryogenic Variable-Density Jets

Kurzfassung

This article summarizes recent results of research on the breakup of turbulent liquid jets. The research focuses on observations of atomization phenomena of cryogenic variable-density jets at various back pressures and injection velocities. The experiments used liquid nitrogen (LN2) as simulation fluid for single-component and LN2/He for binary-component injection studies. The theoreticl assessments show that for binary and multicomponent systems a transcritical region exists where surface tension is present even at pressures above the critical pressure as long as the critical mixing temperature is not exceeded. An important finding is that when approaching the critical point (transcritical regime), capillary forces decrease and a principal change of the atomization mechanism indicated by the change of jet contour length scales and ligaments sizes takes place. A discussion of the transcritical jet breakup regime with regard to classical regimes is presented.