Modeling Droplet Collision with Adaptive Meshing and Updated Outcomes

Improved numerical methods and physical models have been applied to droplet collision modeling. Contrary to the common practice of using the fixed gas phase mesh to calculate droplet collision incidence, a new algorithm generates a collision mesh independent of the gas phase mesh at each time step. By partitioning collision cells according to the number density of parcels, the algorithm is capable of achieving higher spatial resolution than that of the gas phase mesh. At the same time this method maintains an adequate statistical sample of parcels in the collision cells to ensure statistically accurate results. The continual random rotation of the mesh ensures that parcels that are near each other will, on average, be in the same collision cell. This produces the physically reasonable result that parcels in close proximity should have the opportunity to collide. Another important advantage of the algorithm is that it can be applied to any orifice configuration. The influence of the adaptive mesh on high-pressure non-vaporizing diesel sprays was explored. To simulate satellite droplet formation upon collision, a modification is made to an existing droplet shattering model.