Influence of Design Parameters on the Air/Liquid Ratio of an Air Induction Nozzle

A two-phase flow parametric study on an air induction nozzle with water and air as the working fluids is presented. Liquid was supplied at the pre-orifice with various inlet pressures ranging from 3 to 6 bar. The interaction between air and water at the molecular level at the orifice exit leads to formation of a strong shear layer that is intensified with the increase in inlet pressure. Thus, it is vital to regulate the ratio of the intake air to the supplied liquid so that the generated micro bubbles fit the design criteria. CFD analysis was conducted using the commercial software STAR CCM+ from Siemens and validated against experimental data to investigate the design parameters and their effect on the ALR. A volume of fluid (VOF) method of the RANS models was used to undertake the air-water interaction. Parameters such as the throat, air orifice, and air inlet diameter, along with the diffuser angle, were investigated. It was found that certain parameters such as the throat diameter have a more significant effect on the air/liquid entrainment ratio than other parameters.