Hydrodynamic cavitation is the formation, growth and subsequent collapse of vapor bubbles in a moving liquid. It is extremely important to determine conditions of cavitation inception and when it starts damaging industrial equipment. In some cases, such as hydrodynamic cleaning it is important to understand how to improve the cavitation phenomenon in order to enhance cleaning properties. The cavitation number is a parameter used to predict cavitation and its potential effects. In this paper we discuss limitations of this parameter and demonstrate that it cannot be considered sufficient to predict cavitation inception and development in the fluid flow. The experimental setup was designed and built to study cavitation inception in various nozzles. RANS SST k–ω turbulence model was used in this study to model turbulent flow in ANSYS Fluent. CFD calculations were compared to experimental results. It was shown that cavitation inception was sensitive to change in nozzle geometry and, since geometrical parameters are not included in cavitation number formula, scenarios of cavitation inception can be different at the same cavitation number.

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Groundwater wells are widely used in the energy sector, including for drinking water supplies and as water source wells in the oil and gas industry to increase production of natural gas and petroleum. Water well clogging, which can happen to any well for various reasons, is a serious problem that can lead to increased power costs due to a higher head to the pump, a reduction in the flow rate and various drawdown issues. If rehabilitation procedures do not take place in time, this can result in permanent loss of the well, and a new well must be drilled, which is not a sustainable approach. Rehabilitation methods for water wells usually include mechanical and chemical treatments, and even though these methods are well established and have been used for many years we can still observe many abandoned wells which could be rehabilitated. In this study, sets of cavitation generators are developed and used in combination with common conic hydrodynamic nozzles. This combination reduces the pressure in the system and makes the cleaning setup much lighter and more mobile. The designed nozzles were successfully used in hydrodynamic cleaning of four water wells.

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