Liquid films are frequently used, for example, to set adhering, immiscible fluids in motion, such as in coating technology (two-layer coating), oil separation, three-phase rectification, or absorption processes. Liquid films are frequently used, particularly for cleaning in the food and pharmaceutical industries (Cleaning-in-Place or Washing-in-Place (CIP/WIP)).

The challenge lies in the lack of detailed parameterization of the factors influencing the mobilization of adherent fluids by the film. With regard to mechanisms of action and efficiency, plant design has thus far relied primarily on empirical values.

In this collaborative project between the Chair of Fluid Mechanics (LSM) at BUW and the Chair of Measurement and Sensor Systems Technology (MST) at TU Dresden, a parameterized, key-figure-based description of the degree of mobilization of the secondary, adherent phase by undulating primary films (“cleaning efficiency”) is being developed, which can be used directly by SMEs for the design of a process or a technical apparatus. SMEs in the simulation industry can implement this into a simulation tool to incorporate more precise correlations between the parameter space and the (cleaning) effect into, for example, the preliminary design of a plant.

Since, among other factors, the wall shear stress—that is, the velocity gradient—has a direct effect on the transport rate, high-resolution flow measurement is required, involving measurement across the open, fluctuating liquid surface. Therefore, the project’s second objective is to develop a flow measurement technique with aberration correction that reduces the undesirable effects of light refraction and enables spatially and temporally high-resolution three-dimensional investigations of multilayer flows with moving surfaces/phase boundaries. In the process, both the 3D measurement system and the aberration correction can be further developed by SMEs in the measurement technology sector into a product ready for series production. 

The project (01IF23613N) of the DECHEMA e.V. research association is funded by the Federal Ministry for Economic Affairs and Energy as part of the Program for the Promotion of Industrial Collaborative Research (IGF), based on a resolution of the German Bundestag.