Research On Fuel Spray Process Coupled With The Flow In The Intersecting Hole Nozzle

Energy saving and emission reduction have become the two major topics of the diesel engine. The characteristic of fuel spray determines the burning rate and emission characteristics of the fuel, and it can be improved by increasing the injection pressure, but the high injection pressure often accompanies seal difficulty, and the reduction of reliability. In this paper, the injector with the intersecting holenozzle is adopted, which can obtain good atomization characteristics at lower injection pressure.In this paper, geometry model of the intersecting hole nozzle is established, to simulate the internal flow of the intersecting hole nozzle and study its internal flow characteristics, and modify the simulation model parameters by the contrast of the experimental value.On the basis of this, establish fuel atomization model coupling internal flow of the intersecting hole nozzle, to simulate spray process of the intersecting hole nozzle. Then validate the effectiveness of the model through comparison of experimental results.With internal flow mathematical model of the intersecting hole nozzle, investigate the influence of the hole angle, injection pressure and chamber pressure on the internal flow characteristics. Analyze the internal flow characteristics of the intersecting hole nozzle and single hole of the same flow area, analyze the influence of liquid disturbance at the confluence of intersecting hole.The results show that the geometry of the intersecting hole nozzle can restrain the cavity effect;Increasing the hole angle can improve the radial velocity component of the nozzle exit, we can set reasonable penetrationthrough the adjustment of the cross angle to avoid the collision of spray and cylinder wall;and increasing injection pressure and combustion chamber pressure has little effect on the radial velocity of the nozzle exit; the radial velocity component of the nozzle exit was significantly greater than that of single hole.After depth analysis of internal flow characteristics of the intersecting hole nozzle, investigate the influence of the hole angle, injection pressure and chamber pressure on the characteristics of fuel spray including spray penetration and SMD, spray angle and spray air entrainment and so on. Further, analyze the spray characteristics of the intersecting hole nozzle and single hole of the same flow area, and the influence of nozzle structure on the spray characteristics.The results show that with the increase of the hole angle, the spray penetration and SMD obviouslydecrease, the spray cone angle obviouslyincreases;and with the increase of the injection pressure, the spray penetration increases, SMD decreases, the spray cone angle has no significant change. The combustion chamber pressure increases, the penetration distance decreases, SMD decreases, and the spray cone angle changes little. The spray effect of the intersecting hole nozzle is better than that of single hole.