Hydrodynamics of laminar jet apparatuses for gas–liquid mass transfer experiments

Abstract Laminar jet apparatuses (LJAs) are employed to study gas–liquid mass transfer and thereby provide insights into the design of technical separation and reaction equipment. The hydrodynamics of the laminar jet determines the operating window of such apparatuses and must therefore be understood for the proper evaluation of experimental results. Although substantial literature exists on free liquid jets, quantitative analyses directly tailored to LJAs and their operating conditions remain scarce. The present work addresses this gap. We investigate all hydrodynamic aspects relevant to the operation of LJAs using computational fluid dynamics (CFD) simulations: the shape of the jet surface (i.e. the gas–liquid interface), the velocity profile within the jet (including the transition from the nozzle to the free jet) and jet breakup. The study is conducted for a square-edged orifice plate nozzle under various flow conditions and analysed using dimensionless numbers. The CFD simulations account for gravity and surface tension and comprise the entire relevant domain (feed line, nozzle, liquid jet and surrounding gas phase). Complementary experiments using a LJA, in which the jet shape was measured, validate the simulation results. The findings provide quantitative guidance for rational design of LJAs and offer a foundation for replacing ad hoc assumptions in the evaluation of the experiments.