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Accueil du site > Évènements > Séminaires > Séminaires IRPHE > Archives IRPHE > 2022

Vendredi 2 Décembre 2022 / IRPHE

publié le

Séminaire IRPHE

Towards a quantitative framework for change of regimes in two-fluid coaxial atomization

Orateur : Nathanaël Machicoane / LEGI, University Grenoble Alps

Abstract : The destabilization and subsequent fragmentation of a liquid phase by a turbulent gas phase is at the core of many applications that aim at producing high-quality sprays. Certain underlying physical mechanisms of spray formation remain unresolved, hindering process efficiency and control. I will present a multiscale characterization of these mechanisms in a two-fluid atomizer. The interfacial instabilities, and resulting large-scale dynamics, are experimentally characterized using two high-speed imaging methods, back-lit optical imaging and synchrotron X-ray radiography. A spatial characterization of the flapping dynamics of the liquid jet indicates that the flapping dimensionality is related to change between shear break-up to bag break-up. At higher gas velocities, the scaling laws of the transport of the interfacial instabilities highlight the change to fiber-type atomization. In addition, I will show how introducing angular momentum (swirl) in the gas co-flow dramatically changes the topology and dynamics of the atomized liquid jet, resulting in drastic changes in the spray. This is important for atomization control applications, such as ensuring engine restart at high altitude in the context of aircraft propulsion.

Date et lieu : le vendredi 2 décembre à 11h00, salle de séminaires IRPHE

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