Topological flow transformations in a universal vortex bioreactor.

• The development of aerial vortex bioreactors led to interest in two-fluid or multiphase flows. • The study is related to hydrodynamics and mass transfer in vortex flows for chemical and biotechnology application. • The vortex bioreactor provides the gentle mixing of ingredients required for the efficient growth of tissue cultures. • The results are of great interest for identify the kinematic parameters of opaque media of the cultured biomaterial. Research into the flow structure in an aerial vortex bioreactor is relevant for developing the methods to grow cell cultures. It is especially important in the case when, with the culture growth in the bioreactor, such parameters of the medium as density and viscosity can significantly change, accordingly altering the characteristic flow regimes. Since the cultivated culture is not transparent in most cases, it is impossible to visually determine the flow regime. Therefore, a detailed study of the regularities of flow regimes in an aerial vortex reactor is of great fundamental and applied interest. The research was carried out in an 8.5 L universal glass aerial vortex bioreactor, with a washer freely floating on its surface and stabilizing the motion of the working fluid. The regularities of the vortex motion of the culture medium depend on its volume and the rotation intensity of the activator generating vortex motion in the air. The air vortex generated by the impeller (activator) above the liquid surface spins the working fluid and a free-floating washer. The study reveals that despite the complex configuration of the flow stabilizing device (a free-floating washer), the observed vortex structure and its dynamics with increasing flow swirl intensity coincides with the structure of a confined vortex flow in a cylindrical container for both single-fluid and immiscible two-fluid configurations. [Display omitted] [ABSTRACT FROM AUTHOR]