جستجوی مقالات مرتبط با کلیدواژه « Ghost Fluid Method » در نشریات گروه « مکانیک »

In this research, hydrodynamic behavior of a leaky dielectric droplet under an electric field is simulated. The level set method is used for interface tracking and the ghost fluid method is used for modeling discontinuous quantities at interface. Using Taylor’s leaky dielectric model, electric field and electric force at the interface is calculated. Simulation results show the droplet deformation and induced flows inside and outside the droplet under an electric field. Droplet deformation dependent on the electric conductivity and electric permittivity ratio of droplet and surrounding fluid can be as elongation in electric field direction or perpendicular to it. The effect of electric conductivity ratio and viscosity ratio on hydrodynamic behavior of droplet is studied. According to the results, increase in these quantities increases the deformation of droplet. Also, the enhancement rate of droplet deformation is decreased by enhancement of electric conductivity ratio and viscosity ratio.

Injection of a liquid into another immiscible liquid and its breakup and formation of droplets has a basic importance in many industrial processes such as liquid-liquid extraction. In this study, liquid spraying process and drop formation in the dripping mode is simulated using a sharp interface method and effect of important parameters on this process such as Weber number, Ohnesorge number and Bond number is investigated. The level set method is used for interface tracking. Some quantities such as pressure and fluid properties are discontinuous across interface. In this research, discontinuities at the interface are imposed using the ghost fluid method. It is observed that by increasing Weber number (from 0.0027 to 0.1875), the length of the outlet liquid is increased about 7 percent and the liquid breakup time is decreased about 52 percent. Also, at higher Weber numbers, the liquid return toward nozzle after droplet detachment is less. Increasing Ohnesorge number (from 0.0002 to 0.189) increases the length of the outlet liquid about 21 percent and breakup time about 151 percent. Also, at higher Ohnesorge numbers, the liquid return toward nozzle is higher. Increasing Bond number (from 7 to 39) leads to the reduction of the length of the outlet liquid and breakup time about 26 and 91 percent, respectively. Also, at higher Bond numbers, the liquid return toward nozzle is less. Another considerable result is the reduction of the size of formed droplets by enhancement of Bond number.