Effect of Nozzle Geometry on Diesel Spray Characteristics under Non-Evaporating and Evaporating Conditions

Paper i proceeding, 2015

To investigate the effect of nozzle geometry on diesel spray characteristics, spray experiments were car-ried out in a spray chamber. Three different single-hole nozzles were used: (1) nozzle N1 - outlet diameter 140 µm with k-factor 0; (2) nozzle N2 - outlet diameter 140 µm with k-factor 2; (3) nozzle N3 - outlet diame-ter 136 µm with k-factor 2. Two constant gas densities of 15 kg/m3 and 30 kg/m3 were maintained under non-evaporating (ambient temperature 40 ºC) and evaporating (ambient temperature 400 ºC) conditions. The range of injection pressure was from 800 bar to 1600 bar. Liquid phase spray penetration and local spray cone angle along the spray profile were measured based on high speed shadowgraph images. In addition, spray momen-tum flux was measured. It was found that the effect of nozzle geometry on the liquid phase penetration and local spray cone angle were different for different gas density and injection pressure. Under non-evaporating conditions, as injection pressure was increased, nozzle N1 without conicity showed slightly slower liquid penetration and larger local cone angle than nozzles N2 and N3 at the density 15 kg/m3. As the gas density was increased to 30 kg/m3, the difference between the three nozzles was more evident. Under evaporating conditions, nozzle N3 with conicity showed shorter liquid phase penetration than nozzle N1. As the gas densi-ty is increased to 30 kg/m3, comparing the two nozzles (N1 and N2) which have the same outlet diameter but with different conicity, nozzle N2 with conicity showed longer liquid phase penetration than nozzle N1 with-out conicity.