Small scale · Work package b and c
The Single Bubble Rig is a square column made of transparent plexiglass (60 × 60 mm internal cross-section, 1000 mm high). It supports the study of isolated rising bubbles, as part of our goal of understanding the multiscale connection between small and large scales in multiphase flows.
Bubbles are generated at the base of the column with injection needles, mounted in a dedicated port, or with capillaries for the large diameters. This covers bubble sizes from 2 to 8 mm. The gas is always air, supplied from the compressed-air line, with the pressure set by a pressure reducer and the flow rate metered by a flowmeter. The liquids are bi-distilled water, used as the baseline for comparison, and ionic liquid solutions prepared from it.
The rising bubble is recorded with a Phantom Miro C321 high-speed camera, using a Neewer NL660 light source for backlighting. Since only one bubble is present and no tracer particles are needed, the images are processed with edge-detection algorithms, which extract the bubble contour in every frame. From it we obtain the rise velocity, the shape and deformation of the bubble, and the drag. The image analysis and post-processing of the experimental data run on an NVIDIA H200 GPU.
Measurement set-up
