A CFD study on spray characteristics of heavy fuel oil-based microalgae biodiesel blends under ultra-high injection pressures

Blended fuels have intrinsic potential for substitution with petro fuel for the purpose of emission control and fuel efficiency improvement. Therefore, in the current study, non-reacting spray characteristics of heavy fuel oil (HFO) combined with microalgal biodiesel as blended fuel under ultra-high injection pressure is numerically investigated. To accomplish this task with spray morphology, the characteristics of spray penetration, spray cone angle, spray volume and Sauter Mean Diameter (SMD) are studied. The OpenFOAM CFD toolbox is employed with Eulerian–Lagrangian multiphase formulation for fuel discrete phase interacting with gaseous continuous phase modeling. Lagrangian particle tracking (LPT) method is applied for the fuel droplet tracking by Lagrangian scheme. Moreover, hybrid breakup model of KH-RT and k − ϵ as the standard model in Reynolds Averaged Navier–Stokes (RANS) are used for liquid fuel core breakup and turbulence modeling, respectively. Computational results are validated against existing experimental data for HFO and good agreements are displayed. Longer spray penetration length with sharper tip, wider spray cone angle, more obese spray volume and lower SMD are obtained for the blended fuels. Overall, it is concluded that HFO-microalgal biodiesel blended fuels present a better fuel–air mixture and improves atomization procedure under high and ultra high injection pressures.