Numerical study of mixing characteristics of triplet impingement injectors

In order to enhance mixing effect,two novel styles of triplet impingement injectors were presented by changing middle jet orifice or the other two jet orifices into cone-shaped orifices.Flow field characteristics of above-mentioned two kinds of injectors and traditional injectors with triple straight-wall jet orifices under conditions of fuel-oxidizer-fuel triplet arrangement were analyzed based on 3-D computational fluid dynamic methods.The numerical simulation results demonstrate that mixing of triplet impingement injectors is principally accelerated by transverse vortices.For the injector with cone-shaped oxidizer jet orifice,the vertex intensity of flow field is lower than that of the injector with triple straight-wall jet orifices.For the injector with cone-shaped fuel jet orifices,there is a definite increase of the vertex intensity of flow field.Mass-weighted average unmixedness was introduced to evaluate the mixing performances of three kinds of injectors.It is indicated that the mixing effect of injector with cone-shaped fuel jet orifices is better than that of injector with triple straight-wall jet orifices and the injector with cone-shaped oxidizer jet orifice is the worst of three.For injector design of chemical laser combustors,oxidizer and fuel jet orifices adopt different styles,for example,the injector with cone-shaped fuel jet orifices,which helps improve mixing effect of oxidizer flow and fuel flow further.