Liquid spray calculations using a Large Eddy Simulation technique

A vaporization droplet model has been implemented into a Large Eddy Simulation (LES) code. Parcels representing varying numbers of physical droplets of specified initial sizes are injected and followed in space and time while exchanging momentum, energy, and mass with the surrounding gas. The method was first applied and validated on a simple test case and subsequently applied on an airblast atomizer geometry at atmospheric conditions. As this is a fairly new approach, more experience is needed before this technique can be used to its full advantage. An important problem with liquid spray simulations is the specification of the fuel in terms of mass flow and droplet size distribution, at the location of injection. The extra computer time required, compared to a gas flow calculation, when including evaporating droplets, is about 20 percent for a case with 6000 droplet parcels.