A Comparison of Experiments and Numerical Calculations of Diesel Sprays

Övrigt konferensbidrag, 2004

Validation of diesel spray behaviour is a necessity when simulating direct injected diesel combustion engines. A problem is that model fuels instead of standard diesel often must be used in both experiments and spray calculations. Therefore a study was carried out where a two-component model fuel (IDEA-fuel) was used both in calculations and in experiments using different optical methods. Penetration and evaporation of a two-component model fuel were calculated using the FOAM C++ CFD library which allows for multi-component treatment of the liquid. The experiments were carried out in the high-pressure, high temperature spray rig at Chalmers. The injection pressure were altered between 700 and 1350 bar and injected through a single-hole nozzle with a diameter of 0.19 mm. The optical methods used were Mie-scattering/LIF, Schlieren/Shadowgraph and direct photography capturing the size and shape of the sprays. Also Phase Doppler Anemometry which measures droplet size and velocity in the periphery of the spray was used. The results show that the model used underestimates spray penetration and droplet size. A comparison of the measurement results indicates that by combining the methods one can achieve a good understanding of the spray characteristics.