Study On The Instability And Breakup Of Liquid Jet In A Coaxial Airflow

A liquid jet is a common phenomenon in various fields.In the internal combustion engine cylinders,fuel injection,split atomization and mixing of fuel and air are the prerequisites for efficient combustion,which has an important impact on engine power,economy and emission characteristics.In addition,the fuel injection atomization process in internal combustion engines is actually the instability process of the liquid jet,which has very important significance for the study on the breakup and atomization of viscous liquid jets.Based on the linear instability analysis,a mathematical model for the instability of a viscous liquid jet in a coaxial twisting compressible airflow has been developed.It takes into account the twist and compressibility of the surrounding airflow,the viscosity of the liquid jet.Then,the established dispersion equation was solved and verified.The paper discusses in groups based on the direction of the surrounding airflow velocity(axial ejection velocity,coaxial swirling velocity,and twisting velocity).Using the established dispersion equation,analyzed the change of jet disturbance growth rate under the different airflow velocity,and discussed the effects of different the compressibility of the surrounding airflow,the liquid viscosity,gas-liquid density ratio,surface tension.It has been clarified that the effect of aerodynamic force and the influence of fluid properties such as the compressibility of airflow through the research of the paper.Based on the established dispersion equation,the development of jet space and the jet mechanism of breakup and atomization were studied.The study has obtained the changing law of jet morphology under different airflow velocity forms.The dimensionless jet splitting length and the split droplet size are taken as the representatives of characteristics of jet splitting and atomization,and the compressibility of the surrounding airflow,liquid viscosity,gas-liquid density ratio and surface tension are discussed separately.Through research,it has been clarified that the effect of aerodynamic force on the jet disturbance shape,and the effect of fluid physical properties such as compressibility of the surrounding airflow on the dimensionless splitting length and splitting liquid under the two different airflow velocity.