Cavitation Flow of Oil and Water Through the Nozzle

Abstract

The hydraulic equipment and elements are designed so that the flow is not significantly affected by the content of gases in the fluid. In the case of cavitation, there is a change in the volumetric amount of gas, which in water is due to the air and water vapour present, and in the case of oils, especially the air content. This phenomenon causes a significant change in the loss coefficient of the element. The problem of cavitation is solved in the literature for water flow, for other hydraulic fluids (e.g. hydraulic oils operated at different temperatures) the problem is still not solved to a sufficient extent. The article deals with the issue of cavitation in systems in which different types of liquids are used. In the introduction, the physical properties of the used liquids are evaluated, because they significantly influence the origin and development of cavitation. Subsequently, an experimental device with a transparent nozzle is described, on which the measurement. The dependence of the loss coefficient and the cavitation number on the Reynolds number is evaluated. Cavitation is evaluated by a high-speed camera, where it is possible to monitor the behaviour of the cavitation cloud.