ABSTRACT
Atomization of liquid sprays is a widely popular application utilized in increasing the efficiency of combustion applications. The number and size of liquid droplets play a crucial role in obtaining the optimal drop size distribution for the reaction and evaporation processes within a combustion chamber. A generalized numerical model that describes the fragmentation phenomena is evaluated and applied to both two- and three-dimensional simulation models for comparison with experimental data.
An Eulerian multiphase model consisting of a continuous air phase and several discrete fuel phases is developed and applied to a simplified 2D axisymmetric and 3D geometry in order to gain a fundamental understanding of the differences, advantages, and limitations in the geometries. Both geometric simulations utilized the same conservation equations that required several user-defined parameters, including the breakage frequency constant and a breakage kernel parameter. The multiphase model was simulated based on a variety of flow conditions and compared with the experimental data. It can be concluded that the 2D model is capable of qualitatively predicting various spray parameters such as total volume flux and Sauter mean diameter, while the 3D model showed good quantitative agreement. The 3D model was also capable of predicting non-zero Sauter mean diameter values at the centerline unlike the limited 2D axisymmetric model. The 3D model demanded greater computational power as expected, though the solution converged at a much faster rate than the 2D axisymmetric model. This is primarily due to the sequential solution procedure required for the 2D model as it involves a greater number of control equations. There are many factors that affect the complexity of a Eulerian multiphase flow and the current paper will facilitate further studies as there are no guarantees to any individual simulation.
