Numerical Simulation of Fuel Droplet Interactions and Breakup

摘要

The objective of the research in this program was to develop Langrangian methods on triangular grids and apply these methods to the calculation of life history and dynamics of fuel droplets. With respect to numerical technology, the two-dimensional code SPLISH was converted to a VAX and then to a CRAY computer. New graphics systems were developed. Further testing of the basic SPLISH hydrodynamic algorithms as well as the surface tension algorithm were performed on internal gravity and capillary waves. A reorganization of the computer code will make the code user-friendly and portable. Now it should be much easier to use, and therefore useable on many new kinds of problems. First previously calculated flows of the distortion and breakup of a droplet due to differences in flow velocities between the droplet and the external media were recomputed to verify the conversion. Then a number of calculation of droplet distortion and breakup due to shear flows were made. Qualitative comparisons to experimental results were made for the case when the droplet density and external fluid density were nearly equal. Our calculation and the experiments by Mason and coworkers showed small droplets torn off the large drop by the forces in the shear flow. A preliminary calculation of a droplet-droplet collision shows the distortion of droplets before they collide. Forced-flow and inflow-outflow boundary conditions, needed to do quantitative comparisons to experimental shear flows, were added to the model.