Spray, combustion and soot of water-in-fuel (n-dodecane) emulsions investigated in a constant volume combustion chamber part 1: Influence of low water content

n-Dodecane and WFE show nearly equal momentum flux and spray penetrations for constant injection pressure, i.e. the first injection strategy. Compared to neat fuel, ignition delay is gradually increased with addition of water. Measured quasi-steady lift-off lengths (LOL) increased and evaluated fuel-to-air ratios Φ at axial LOL decreased, however, for both WFEs differences of Φ are within their respective standard deviation. Increasing water contents reduce axial and radial soot extension as well as the optical soot densities (KL factor). Moreover, the injection strategy of constant injected energy input flow further decreased soot area and optical soot densities (KL). Decreasing fuel-to-air ratios Φ on the spray centerline at the axial soot inception location and increasing fuel flow residence times from LOL to axial start of soot formation with increasing water mass fractions indicate a direct influence of the water content in WFE on soot formation/oxidation processes.