Film thickness measurement in oil-water pipe flow using image processing technique

Dispersed oil-water flow was studied in a 12 m long horizontal acrylic pipe, with 26 mm of internal diameter, using mineral oil (828 kg/m3 of density and 220 cP of viscosity) and tap water. Experiments with a high-speed video camera were performed to obtain images of the flow near the pipe wall in highly dispersed oil-water flow. A visualization section was properly designed and installed in the pipeline for that purpose. The technique applied in the present work is based on the acquisition of images of the flow, and then the application of digital image processing techniques in order to quantify the film thickness near the wall. A thin water film was detected at the top and bottom of the pipe at highly turbulent oil-water flow. A pre-processing enhancement algorithm and a combined segmentation algorithm are being proposed to measure the film thickness. A comparison with a phenomenological model is also presented. The combined method performs better when compared with the results obtained from the application of the traditional techniques individually.