For the better application of the self-pressurized injector on aircraft piston engines

the spray characteristics of a self-pressurized injector was experimentally studied in a constant-volume vessel. Spray characteristics of RP-3 aviation kerosene under different ambient pressure

fuel temperature and ambient temperature were studied using visualization technology combining Matlab image processing program. Result showed that

the surface waves and fuel strings can be observed obviously under the ambient pressure of 0.1 MPa. With the ambient pressure increasing from 0.1 MPa to 0.8 MPa

the typical hollow cone spray was transformed into a hollow cone spray with large scale vortexes. The maximum spray penetration reduced by 45%

and the maximum spray area reduced by 55.3%

respectively. The increase of fuel temperature promotes spray evaporation to facilitate cold start. The spray penetration

area and cone angle were all minimum when the fuel temperature was 50 ℃. At the ambient pressure of 0.1 MPa

the spray penetration and area increased at first and then decreased with the increase of ambient temperature. The maximum spray penetration reached 67.3 mm at ambient temperature of 60 ℃

the maximum spray area reached 915.5 mm2 at ambient temperature of 50 ℃

respectively. The spray cone angle decreased with the increasing of ambient temperature

reaching the minimum value of 9.2° at ambient temperature of 90 ℃.