A Set of Instruments Useful for Liquid Quality Control During Cavitation Research

Abstract

It is well-accepted by investigators of cavitation phenomena that undissolved and dissolved gas content in the liquid used affect the onset and type of cavitation in many cases. That is why not only cavitation studies have been carried out to understand the hydrodynamic properties and interactions but also to get insight into the relations between cavitation and liquid quality. The liquid quality is a criterion which gives information about the dissolved gas content and about the undissolved gas content in terms of size distribution and concentration of bubbles and gas pockets dispersed in the liquid. Although not every detail of the interaction between cavitation (inception) and liquid quality is known, it is at least necessary to control and to know the liquid quality. In this way experiments become repeatable and the investigator is allowed to focus his attention to hydrodynamical questions only. In this paper some new and modified instruments and control systems in respect to liquid quality are described. They are an automatic dissolved air (gas) content meter, an acoustic doppler system for bubble detection and a bubble filter for injection of a known bubble mixture.