NUMERICAL SIMULATION OF COLD FLOW WATER DIESEL EMULSION SPRAY

A numerical simulation is performed for spray injection into an initially quiescent air in a constant volume chamber, using OPENFOAM software. The hybrid, Eulerian-Lagrangian formulation is used where the continuous-phase equations are written in an Eulerian form and the governing equations for the discrete, spray parcels are considered in a Lagrangian framework. A compressible version of the k- ε model is used for turbulence modeling. The simulation of spray consists of several submodels, including the atomization model, the breakup model, and models for drag and gravitational forces. A case is numerically simulated and compared with experimental data, as well as others' numerical predictions. The present results are in good agreement with the experimental data. Effect of water addition to diesel fuel is studied in cold condition and some characteristics such as the spray structure and size distribution of droplet diameters are presented. Water addition appears to have little effects on the spray tip penetration, but changes the size of droplets.

Keywords:

water-diesel emulsion , spray tip penetration , droplet size distribution