使用CFD方法优化共轨喷油器孔板结构

Application of CFD in Optimizing Geometry of Orifice-plate in Common Rail Injector

针对新设计的2种结构控制阀孔板在相同设计流量比下,喷油器开启压力值及其散差相差较大,无法满足设计要求的问题,在考虑了喷油器控制阀孔板加工和检测过程等因素的前提下,提供了一种通过流动计算预测开启压力的方法,在此基础上,研究了2种新开发的孔板开启压力及其散差,计算结果表明:开启压力对孔板A进油量孔加工误差非常敏感,是造成孔A开启压力散差较大的原因,孔板B的控制腔进油量孔的导向孔内多处有回流和漩涡,增加了燃油流动阻力,即作用在控制活塞顶部压力更小,而导致其开启压力较低,根据计算流体力学(CFD)计算分析结果,改进优化了孔板A,B的结构,以满足喷油器有较高的开启压力,较小的散差的设计要求,试验结果表明:改进优化后,孔板A的开启压力散差有所减小,孔板B的开启压力有所提高。

In the design process of injector,two types of orifice-plate are evaluated.Experiment show that in injector A,where orificeplate-A is used,both the opening pressure and its dispersion are larger,and in injector B,where orifice-plate-B is used,the opening pressure and its dispersion are lower.In the paper,In considering the effect of processing method and machining error,provide a method to predict the opening pressure by CFD calculation.Two types of orifice-plate are simulated by this method.The results indicate that plate-A＇s dispersion of the opening pressure is large and is very sensitive to machining errors.In plate-B,because there are many refluxes and vortexes in the guide hole,the flow resistance increases,effective pressure on piston is less,leading to smaller opening pressure.The structure of plate A and B are optimized,based on the results of CFD calculation.The requirement that is to design the injector with higher opening pressure and lower dispersion are met.The experiment results indicate that in injector A,where orifice-plateA is used,the dispersion of the opening pressure decreases,the modified plate-B＇s opening pressure increases.