摘要
应用PIV实验方法对由直射流和同心的环状旋转射流组成的双射流流场进行了测量,并分析研究了流场的速度和旋度变化规律。分析表明,双射流等速核长度较小,仅约为5倍喷距;随喷距的增加其多股射流特性逐渐减弱,其主要原因为直射流和旋转射流在交界面上很强的剪切作用;旋转射流的径向发展因受直射流吸附作用的影响而减小,相应直射流速度在喷嘴轴线上的衰减则增加。在4-6倍喷距间的旋转射流速度突然下降和相应位置处旋度场的涡环都显示该处可能存在较强的空化现象,而大大提升双射流的能力。
The experimental results on the flow structure and mixing of a dual jet are presented. Particle Image Velocimetry （PIV） system was used to acquire velocity and vorticity profiles, and the dual jet was formed by combining a round straight jet with a concentric annular swirling jet. Analysis of velocity attenuation profile demonstrates that the dual-jet has a short potential core, which is only about 5 times nozzle diameter in length and as a result of the strong interaction between two jets, the multi jet feature fades out with the increasing of the distance from nozzle, While the radical development of the swirling jet is limited by the attraction of the inner jet, the attenuation of jet velocity at nozzle axis is accelerated. At the distance of 4-6 times nozzle diameters, both the abrupt velocity drop and the vortex indicate the induing of cavitation phenomenon, which can dramatically improve the capability of the dual-jet.
出处
《水动力学研究与进展（A辑）》
CSCD
北大核心
2006年第1期90-94,共5页
Chinese Journal of Hydrodynamics
基金
国家自然科学基金重大计划面上项目(90410007)
教育部创新团队计划(IRT0411)资助
