Numerical Study of Scale and Shape Parameters of Droplet-Size Distribution in Air-Assisted Atomizer

Abstract

The article is devoted to the development of approach to study the atomization in an air-assisted atomizer by the volume- of-fluid method. Received through the simulations in the axisymmetric swirl approximation, the ligament-size distributions were approximated by the translated Weibull distribution, which is determined by the scale, shape and location parameters. The dependences of the latter two parameters on the surface tension, viscosity, density and flow rate of the atomized liquid are a subject of this research. Since the problem hasn’t been well studied before, there is no convenient approach to determine the location parameter and as a result, we use two ways to find it. The first one is by changing the parameters of the translated Weibull distribution with aim to fit the ligament-size distribution as best as possible. The second one is by equating the location parameter to the minimal ligament size where the ligament-size distribution is zero. The choice of the approach not only changes values of the parameters, but also leads to appearance or disappearance of the dependence of the location parameter on the properties of the atomized liquid. Nevertheless, if the very weak decrease of the shape parameter on the surface tension is neglected, this parameter of the Weibull distribution doesn’t depend on the parameters of the liquid. Moreover, this conclusion is the same for both approach to determine the location parameter.