Effect of dwell-time on multi-component fuel vaporisation of high-pressure Diesel sprays injected from cylindrical and reverse tapered multi-hole nozzles

The effect of dwell-time, fuel composition and nozzle hole shape on the development of dense Diesel sprays injected from high-pressure multi-hole common rail injector nozzles is evaluated using a validated computational fluid dynamics spray model. The initial conditions required as input to the model have been estimated by a multiphase nozzle hole cavitation model. The subsequent liquid plume development is predicted using an Eulerian- Lagrangian spray model, which accounts for liquid-core atomisation, droplet aerodynamic break-up, turbulent dispersion, droplet-to-droplet interaction and multi-component fuel vaporisation. The physical properties of the liquid fuel follow those of specified composition of pure hydrocarbons; the effect of different composition on the spray development during pilot and main injection periods is assessed. In the absence of experimental data to characterise the detailed spray structure under such operating conditions, the computational results presented in this work aim to provide some useful information about the effect of multi-injection strategy on fuel vaporisation characteristics under conditions typical of direct injection, turbocharged, high-speed Diesel engines.