MODELING OF THE OPERATING MODES OF THE EJECTOR-CAVITATOR TO DETERMINE ITS OPTIMAL DESIGN AND TECHNOLOGICAL PARAMETERS

The article presents the results of the development and scientific substantiation of the technology of cavitation activation of natural zeolites of the Sokyrnytske deposit (Transcarpathian region) and the Nyzhnohrabovetske deposit (Slovakia) to significantly increase their sorption capacity for heavy metal ions (Pb, Cd, Zn, Cu, etc.), radionuclides (¹³⁷Cs, ⁹⁰Sr) and nitrogen compounds (nitrates, ammonium). The use of hydrodynamic cavitation in a Venturi tube and a modified ejector-cavitator is proposed as an environmentally safe, energy-efficient and reagent-free method of modifying sorbents, which fully complies with the principles of green chemistry and the objectives of the Water Strategy of Ukraine until 2030. A comprehensive CFD modeling (Ansys Fluent 2023 R2) with a multiphase VOF+URANS approach, a Schnerr-Sauer cavitation model, and a discrete-phase model for estimating trajectories and collapse of cavitation cavities was performed. The independence of the solution from the computational grid was verified with more than 100 thousand elements. Single-phase and multiphase modelingswere compared. The multiphase approach provides physically realistic values of pressure (up to 215 atm) and temperature (~800 K) of cavity collapse, while the single-phase approach significantly overestimates these parameters, but is suitable for quick qualitative assessment and preliminary optimization of geometry and operating modes. The optimal inlet pressure of 7 bar was established, having which the maximum intensity of the cavitation effect is achieved with minimal energy costs. A hybrid optimization strategy was developed, which consists of the initial rapid screening of promising designs by single-phase modeling with subsequent detailed multi-phase analysis of the best options. Based on the results of modeling the operating modes of the ejector-cavitator, its optimal design and technological parameters were obtained. Using the obtained data, a laboratory recirculation unit (volume 20 l, pump 1,1 kW, pressure regulation up to 10 bar) and an ejector-cavitator design for manufacturing by 3D printing from cavitation-resistant Spectrum PP polypropylene will be created. The obtained results are a scientific and technical basis for making highly efficient sorption materials and water purification technologies with high potential for industrial scaling.