Numerical analysis of the flapping mechanism for a two-phase coaxial jet. (September 2018)

• Record Type: Journal Article
• Authors: Odier, Nicolas; Balarac, Guillaume; Corre, Christophe
• Is Part Of: International journal of multiphase flow. Volume 106(2018)
• Page Start: 164
• Page End: 178
• Publication Date: 2018-09
• Subjects: Coaxial jet -- Two-phase flow -- Flapping dynamics -- Parametric study; Multiphase flow -- Periodicals; Écoulement polyphasique -- Périodiques; Multiphase flow; Periodicals; 620.1064
• DOI: 10.1016/j.ijmultiphaseflow.2018.05.028
• Languages: English
• ISSNs: 0301-9322

Abstract

Highlights: The flapping mechanism of a two-phase coaxial jet is numerically investigated. This flapping dynamics is characterized, and a mechanism is proposed for this coaxial instability. A sensitivity study to the high-speed stream boundary layer thickness, the velocity ratio, and the momentum flux ratio is performed. The momentum flux ratio is not found to characterize alone neither the flapping dynamics, nor the atomization. Abstract: A numerical study of a coaxial liquid jet sheared by an annular high-speed stream is performed at moderate density and velocity ratio between phases. The destabilization mechanism of the jet is studied : due to the shear induced by the high-speed stream, annular interfacial waves are generated near the jet injection, which subsequently connect and yield a sinuous organization for the whole jet, leading to a global flapping phenomenon. The influence of the high-speed stream boundary layer thickness on this flapping is investigated, as well as the influence of the velocity and the momentum flux ratio between phases. It appears that it is not sufficient to consider only the momentum flux ratio between phases to characterize the flapping dynamics or the steps of the atomization process. On the other hand, the Reynolds and Weber numbers based on the high-speed stream properties display a strong influence on these phenomena.