Numerical investigation of an air-water ejector in submerged application

Details

Supervisors

Bartosiewicz, Yann ; Duponcheel, Matthieu

Faculty

Ecole polytechnique de Louvain

Degree label

Master [120] : ingénieur civil mécanicien, à finalité spécialisée

Abstract

The objective of this Master’s thesis is to investigate numerically the behavior of an air-water ejector in submerged applications. Air-water jets are employed in several engineering domains such subsea cleaning, transporting multiphase flows, gas recirculation technology, and industrial cooling systems where maintaining the stability of the air layer is crucial for enhancing jet performance and reducing energy losses. However, the mechanisms that govern air suction, air layer formation, and interface stability within multiphase submerged ejectors remain insufficiently understood. This work aims to explore the key factors that influence the suction of air in an ejector system and to identify their numerical implementation that optimize simulation accuracy and stability in Ansys Fluent. More specifically, the study compares two multiphase flow models : the Mixture model and the Volume Of Fluid (VOF) model, as well as the selection of pressure-velocity coupling schemes (SIMPLEC, Coupled) in order to determine which models and schemes provide the most reliable predictions of air entrainment. Subsequently, parameters such as drag and drift forces are analysed. After that, attention is paid to the boundary conditions. The influence of air inlet pressure on the air entrainment is then conducted. The results provide significant insights into the dynamics of submerged liquid-gas ejector and contribute to the optimization of ejector design to improve performance in practical applications.