Development of a method for calculating the gas-optically transparent liquid interfacial surface area based on a 2D image

The interfacial surface is the principal factor ensuring the efficiency of chemical engineering processes in gas–liquid systems. The most reliable method for registering the interfacial surface is high-speed cinematography, since the process is characterized by a complex interfacial structure and a high rate of occurrence (the period of ultrasonic oscillations does not exceed 46 μs). Within the framework of this study, the objective was to develop and implement an improved method for processing a high-speed cinematographic still frame of a gas bubble in a liquid as a function of its viscosity. To achieve this objective, an integrated approach was applied, including the use of modern specialized computer vision libraries for image processing, appropriate image filtering methods, and the most suitable programming languages. A correlation was established between the interfacial surface area calculated from the contour length and the average energy of the harmonics of the spatial distribution of light intensity in the image. An algorithm for reconstructing the profile of the interfacial surface based on image brightness gradients was developed, and its individual stages were tested using the profile of a test image of the liquid–bubble interfacial surface obtained by high-speed cinematography of the ultrasonic oscillation effects on a barbotage process. The existence of a limiting viscosity at which an increase in the interfacial surface is achieved was established.