摘要
利用PIV技术,在相同喷射压力下对分属液膜射流和圆形射流的两种理论喷射类型的典型喷油器———涡旋喷孔和双喷孔喷油器的射流雾化的湍流演化过程进行了测量和分析,研究表明:在整个射流过程中,两种射流的空间相对湍流强度分布比速度分布发散,且集中分布在射流的上下边缘和根部区域;随着喷射时间的延长,射流流场的湍流强度值逐渐增大,且主要分布在涡旋射流的非前锋区域以及双孔射流的非前锋和非中心线区域;喷射开始后1.5ms和4ms时,涡旋射流中心区域的湍流积分尺度分量值较大,分别达到约6mm和7mm的量级,8ms时,涡旋射流流场的湍流积分尺度分布的发散程度比双孔射流明显,且雾化粒子速度方向与积分方向不同时得到的两个湍流积分尺度分量大小以及连续性等分布情况恰好相反;整个喷雾过程,雾化粒子y方向速度分量沿x方向积分得到的湍流积分尺度分量值均小于其他3个湍流积分尺度分量值且分布的不连续性明显。
The PIV technique was applied to study the turbulent characteristics of the spays through the swirl injector and the double-jet holes injector which belong to the typical spray models called liquid-film spray and cylindrical spray respectively.The Spatial Turbulent Intensity（short for＂I＂）and the Turbulent Integral Length Scale（short for＂ILS＂）were used as parameters to analyze the turbulent characteristics of the two typical sprays.The result indicated that in the whole spray process,the distributions of I-values for the two kinds of sprays were diffuser than the distributions of speed-values,and the I-values were mainly distributed on the regions of the upside,downside and the root side of the spray flow fields.With the spray is continuing the I-value of the spray flow field,the I-value of the spray flow fields became higher and its distributions mainly concentrated in the regions of the non-front for the swirl spray and the non-front,non-central line for the double-jet spray.In order to simulate the ILS distribution more convenient,the ILS-value of every point of the spray flow field was decomposed into 4components：Lxx,Lyx,Lxy,Lyy.Begining with the injectors spraying,at the time of 1.5ms and 4ms,the Lxx-value of the swirl spray was higher than the double-jet spray and was also higher than the 3other components at the same time;the local values of the Lxx reached the scales of 6mm（1.5ms）and 7mm（4ms）.At the time of 8ms,the distributions of all components for the swirl spray were diffuser than the double-jet spray;at the same time,the distributions including values and integralities of Lyxand Lxy were completely contrary.In the whole spay process,the distributions of Lyxfor the two sprays were obviously lower and less integrated than the 3other components respectively.
出处
《空气动力学学报》
CSCD
北大核心
2014年第2期214-218,227,共6页
Acta Aerodynamica Sinica
基金
国家自然科学基金(50376075,51246010)
关键词
液膜
圆形射流
PIV
湍流强度
湍流积分尺度
liquid-film
cylindrical spray
PIV
turbulent intensity
turbulent integral length scale
