Scientists at Novosibirsk State Technical University (NSTU) are engaged in a comparative study of optical methods — Hilbert optics, speckle interferometry and laser-induced fluorescence, which will help control the process of hydrodynamic cavitation, namely— to control the nucleation, growth and collapse of cavitation cavities in liquids.
As part of the national "Bioeconomics" project, scientists are paying attention to nature-like technologies that copy natural processes. One of these processes is hydrodynamic cavitation, which is the formation and subsequent "cold boiling" of bubble cavities in a liquid stream.
The energy of the hydraulic shock resulting from the collapse of cavitation cavities can be used to solve a variety of applied problems, from the intensification of mixing and emulsification to surface cleaning and disinfection of liquids, which makes this phenomenon in demand in the food, chemical, pharmaceutical and water treatment industries.
However, the practical implementation of cavitation technologies faces serious difficulties: the process is influenced by many hydrodynamic and thermodynamic factors (pressure, temperature, flow velocity, liquid properties), which makes it difficult to control in real technological cycles.
"To overcome this barrier, we intend to study in detail the key parameters of the process — the energy released during the collapse of individual bubbles, local temperatures in the collapse zone and the dynamics of changes in these parameters over time. Based on the experimental data obtained, a mathematical model will be developed that describes the relationship between control actions and the response of the cavitation field. Such a model will make the process predictable, manageable and, therefore, suitable for large—scale industrial applications," said Anna Pronchenko, a graduate student at the Department of Laser Systems at the Faculty of Physics and Technology, NSTU-NETI.
According to the researcher, the study of methods of Hilbert optics, speckle interferometry and laser-induced fluorescence (LIF) will help control the process of hydrodynamic cavitation, which opens up new prospects in biotechnology and the food industry, where cavitation control is critically important for the quality of final products.
"To develop physical methods of cavitation control, we conducted a series of experiments on a laboratory stand, which consists of a hydrodynamic cavitator, a circulation pump, a plexiglass cuvette and an optical registration system. This scheme will allow to implement three independent optical approaches in luminal geometry, differing in the way of processing transmitted or scattered radiation," said Anna Pronchenko.
"The results obtained will allow us to determine a strategy for further research, select a calibration stage methodology, and select the optimal way to track cavitation parameters in real time," the scientist noted.