Calculation of Three Dimensional Spray Motion in Engines

Multidimensional calculations axe presented of the behaviour of sprays injected into the combustion chambers of motored reciprocating engines, in circumstances giving rise to three-dimensional spatial variations in the droplet and gas flow fields. The calculations were performed using the implicit EPISO algorithm, extended to include a Lagrangian description of the spray. The gas-phase turbulence is represented by the κ-ε model and its effect on the droplets is modelled stochastically. Two applications of the method are reported: one involves the simulation of, and comparison with data from, published experiments on a laboratory engine fitted with a single-hole injector in the cylinder wall. The second case is a demonstration calculation for a direct-injection Diesel with a cylindrical piston bowl and a four-hole injector. The comparisons in the former case with the measured spray penetration are favourable, but since this was the only measured feature no firm conclusions could be drawn about the overall accuracy of the simulation. Both sets of calculated results do however provide considerable insight into the two-way interactions between the spray and the in-cylinder flows in particular they show important effects resulting from non-uniform droplet sizes.