Numerical Study on the Effect of an Annulus Injector on the Hydrodynamic Behavior of a Spray

In the internal combustion engines geometry of the injector orifice has significant effect on the improving of the fuel spray characteristics. In the present paper, effect of a conical annulus injector with three different aspect ratios and three different divergence angles of the annulus orifice on the hydrodynamic behavior of a fuel spray have been investigated numerically. The conical annulus injector aspect ratio is the ratio of the height of the annulus cone to the diameter of its circular base. The geometry of the annulus conical injectors inspires this idea that this type of injectors could inject possible large amount of liquid fuel into a combustion chamber symmetrically and homogeneously. The CFD software AVL Fire has been employed for numerical simulation of diesel fuel spray evolution. Numerical results show that the annulus conical injectors inject liquid fuel with an approximately homogenous distribution of droplets in the combustion chamber in comparison with the conventional injectors. In this kind of injector, fuel has been uniformly distributed in the cylinder. Numerical results also show that the annulus injectors significantly increase the cone angle of the liquid fuel spray and decrease its penetration length.