Investigation on characteristics of fuel impinging wall and mixture forming in diesel engine

Fuel impinging on the wall was calculated by using STAR-CD with 3-D model. The emphases of investigation were the spray angle, environment pressure and swirl ratio affecting on the impinging and mixture forming. The results show that the secondary atomization after impinging is very important to the fuel evaporation. When spray angle increases, the area of film on the wall increases too. The shape changes from long-leaf form to sector. When environment pressure becomes higher, the distribution of fuel reduces obviously, and fuel deposit and rich mixture area decreases. Relative lean mixture is formed. The effect of swirl on the fuel happens after impinging wall. Along with swirl ratio increases, large-scale lean mixture formed. If swirl ratio is too higher, the mixture of adjoining sprays will be in collision with each other, which is disadvantageous for combustion.