Hydraulic characteristics of the convergent-divergent nozzle with the inner electrode in cavitating conditions

Abstract

The knowledge of hydraulic characteristics of convergentdivergent nozzles will lead to the optimal design of a nozzle for generating a cavitation cloud. Such a nozzle is a crucial component of the CaviPlasma device, which aims to tackle the ever-growing water treatment and purification issue. To measure the characteristics, a closed hydraulic circuit was used to measure pressure differences before and behind the nozzle, and the flow rate. The characteristics were then developed based on the calculated loss coefficient ξ and the cavitation number σ. Three different nozzle designs were tested (with diameters of necks 3 mm, 4 mm, and 5 mm respectively), and multiple positions of the inner electrode were set for each design. This resulted in several characteristic curves for each design and electrode position. The study will contribute to the development of an optimal nozzle for the CaviPlasma device, enhancing its efficiency in water treatment and purification.