Influence of Nozzle Configuration on Spray Characteristics of Multi-Hole GDI Injector

Nozzle configuration directly determines the flow state in multi-hole non axisymmetric GDI injector,thereby affecting its atomization characteristics. A model for different inner circle chamfering, length-diameter ratio and spray cone angles of the nozzles were established. The EDM(electro-discharge machining)and abrasive flow technology were used to process the nozzle samples. CFD simulation,highspeed photography and laser measurement were used to analyze and validate the effects of different nozzle parameters on spray pattern,penetration distance and probability density of sauter mean diameter. Results show that,inner chamfering of nozzle effectively decrease the cavitation of nozzle inner flow and increase penetration distance,while sauter mean diameter of spray is slightly increased. The length-diameter ratio of nozzle impact on cavitation is unobvious,and the effect on penetration and sauter mean diameter does not follow a linear law. The nozzle cone angle impact on cavitation is also unobvious. Spray penetration distance is decreased with increase of nozzle cone angle,but individual spray cone angle is increased, leading to the improvement of atomization.