A coupled Volume-of-Fluid and Lagrangian Point-Particle approach for investigating the plain liquid jet in crossflow atomization

Kurzfassung

The atomization of a liquid jet in crossflow is revisited for the density ratio corresponding to conventional Jet A-1 aviation fuel by numerical simulations. To correctly capture the large range of spatial scales involved, the coupled methods of momentum conserving Volume-of-Fluid and Lagrangian Particle Tracking methods are used. Both solvers are combined via momentum coupling and two-way droplet conversion. Additionally, we take advantage of Adaptive Mesh Refinement to save computation time. The Lagrangian method is free from coalescence and breakup models, therefore a global criterion is applied to avoid droplet transfer from the VOF solver to the Lagrangian solver in the region with a high number of coalescence events. To achieve this, a new post-processing method for identifying coalescence and disintegration of droplets is described. The Lagrangian method is validated regarding single droplet trajectories, and a qualitative validation of the Euler-Lagrange conversion is presented. Two different sets of inflow velocities for the gaseous and liquid phases are investigated. The results obtained with the coupled Euler-Lagrange method show a good agreement with those from pure Eulerian VOF simulations, regarding droplet size and velocity distributions and column breakup point. Jet penetration is validated, and the Sauter Mean Diameter is close to experimental correlations. A significant reduction of computational cost is achieved by the coupling to the Lagrangian method.