Properties effect of blending fischer-tropsch aviation fuel on spray performances

Abstract

The physical properties of fuels have significant impact on the spray performances. Fischer-tropsch (FT) aviation fuel is mainly composed by paraffins compared with Chinese jet fuel (RP-3). Difference in composition determines the differences in physical properties. Spray characteristics of FT and the blends were investigated downstream of a pressure swirl nozzle exit at different injection pressures and compared with those of RP-3. The liquid length and the spray cone angle of FT fuel are up to18.2% and 6.75% higher than RP-3, respectively. In the area where the axial distance from nozzle exit is less than 10 mm, FT fuel has a higher droplet size and droplet velocity than RP-3. A reflux zone is observed in the hollow cone downstream the nozzle. The droplets' droplet diameter and velocity of FT fuel are 53.32% and 49.74% bigger than those of RP-3 in the reflux zone, respectively. The presence of the reflux zone is also believed to be responsible for the higher local droplet concentration in the spray. The spray performances of the blends containing 75% FT is close to that of RP-3. The differences in spray performances between the fuels are consistent with the expectation based on differences in physical properties.