Theoretical determination of the mixer inner ring minimum allowable diameter to produce a two-phase mixture

Abstract

When flushing marine systems and their components, a mixed flow of water and air can be used. This method of intensifying the flushing process of ship systems brings tangible results, but currently has a number of unresolved tasks. One of these tasks is the issue related to the risk of cavitation phenomena when using a two-phase mixture. The occurrence of cavitation depends on a number of factors, but primarily on the mass content of air in the water stream. An attempt has been made to assess the development of cavitation in the elements of a mixer used to produce a stable mixture of water and air. The design of the mixer is considered. The main theoretical dependence of the minimum allowable diameter of the narrow ring of the mixer on the main parameters of the mixed flow is determined: the densities of the phases of the mixture, the mass content of air in the stream, the initial diameter of the pipeline and the compression ratio of the jet in a narrow section, as well as on the initial pressure of the flushing flow. In the study of cavitation phenomena, a homogeneous model of a two-phase mixture was used as the most suitable for the flushing mode with a two-phase pulsating flow. The main calculation dependencies for determining the minimum allowable diameter of the narrow ring of the mixer are determined. The influence of various factors on the development of cavitation phenomena has been assessed. Recommendations are given on the choice of the diameter of the narrow ring of the mixer.