Bubbly flows play a significant role in various industrial and geophysical processes: chemical and nuclear reactors, atmosphere-ocean exchanges. In addition, the current technologies to capture carbon dioxide involve chemical reactions between CO2-bubbles and liquid reagents. Nevertheless, the current design of these devices is still based on global empirical correlations.
Predicting the motion of bubbles, how they affect the liquid phase and the associated heat and mass transfer are still crucial problems in fluid mechanics even without phase transitions and chemical reactions.
This project aims to investigate and quantify the transport mechanisms of a diffusive scalar field in gravity-driven turbulent bubbly suspensions using fully-resolved Direct Numerical Simulations (DNS). The computational challenge is to study for the first time the transport of a scalar (like temperature or concentration) at Prandtl/Schmidt numbers up to seven (comparable with the values of water). In these regimes, the simulation cost increases up to thirty/forty times compared with a case without scalar transport, given the necessity of resolving the fine length scales induced by the diffusivity.
The new scientific knowledge and the produced numerical database can be used to formulate new mathematical models to design more efficient and sustainable chemical reactors.