Numerical study of Critical Flow Venturi Nozzles for massflow metering of high-pressure gases

The present study investigated the effectiveness of numerical models in view of obtaining reliable evaluations of nozzle flow structure in critical conditions. In particular, this project focused on three essential points: 1. The detailed characterization of the capacity of different RANS models to capture the growth of laminar or turbulent boundary layer in situation of highly accelerated or decelerated flows. 2. The integration of laminar to turbulent transition models. 3. The study of the influence of the gas properties (air versus hydrogen) on the flow structures. The simulations were carried out with the open-source CFD code SU2 for which dedicated python-based pre and post-treatment tools were currently developed.