A Study of ECN spray A Using an Improved Stochastic Blob (VSB2) Spray Model

Accurate prediction of spray formation is crucial when modeling spray combustion. In this work an existing Eulerian-Lagrangian spray model, VSB2 has been extended to account for secondary break-up in a more accurate way, by creating child blobs from the stripped of mass for each blob undergoing break up. The new break-up approach was compared with the old approach for two different parametric variations of the ECN spray A refer- ence case. It showed that the new method predicted more accurate liquid penetration with the effect being more pronounced at lower ambient temperature. It was concluded that with the new break up treatment, smaller blobs from the stripped off mass is created downstream of the spray, causing the liquid to evaporate faster as the smaller blobs with less momentum have an increased radial dispersion into the bulk as they will be affected more by the drag force. More heat is available to evaporate the fuel outside in the bulk. A reduction in turbulence was also observed due to the smoother velocity gradients generated by the smaller blobs.