Influence of fuel injection parameters on the flow process of gasoline-wall interaction
Using the schlieren method,the influence of fuel injection pressure,ambient pressure,collision distance in the constant volume chamber on spray characteristics after direct injection gasoline hit piston head were investigated.The results show that after the gasoline hits the piston,a counterclockwise rotating vortex area is formed on the right side of the collision point.The formation of vortex promotes the reduction of the area of the thickened zone.Increasing injection pressure,reducing ambient pressure and collision distance can reduce the area of the thickened zone at the same injection time.Fuel injection pressure and ambient pressure have little effect on the left diffusion length S1,but S1 decreases significantly as the collision distance decreases.When the collision distance decreases from 18.1 mm to 12.3 mm,S,reduces from 20.9 mm to 16.3 mm after injection.The right diffusion length Sr increases with the increase of fuel injection pressure,the decrease of ambient pressure and the shortening of the collision distance.When the ambient pressure is less than 0.5 MPa and the collision distance is greater than 18.1 mm,there is a risk that the spray may rush out of the top surface of the piston.The spray diffusion area increases with the increase of fuel injection pressure and the decrease of ambient pressure,and increases with the increase of collision distance.
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