不同温度气体喷射特性的PIV试验研究

研究气体的喷射特性,用于指导发动机燃油供给系统的设计和燃烧室有效组织燃烧。基于粒子图像测速技术(PIV),对不同温度、不同压差下气体喷射的特性进行了对比研究。通过试验分析和图像处理等手段对射流流场及涡结构、气体射流边界扩展、喷嘴轴向流速衰减规律、断面流速分布等进行了总结。试验表明:射流边界呈线性扩展,可用锥角大小来表征其特性,锥角随压差的减小而增大,且增幅明显,温度对其也有一定影响。喷嘴射流的轴向速度与射流距离成反比,而速度的影响面积随射流距离的增大而增大,温度的增大使得相同压差下的轴向速度相应增大,断面流速的分布存在很大的相似性。

Experimental Study of Gas Injection Characteristics at Different Temperatures with PIV

In order to guide the design of the engine fuel supply system and combustion effective organization,characteristics of a gas jet were discussed. Different temperatures,different pressure gas injection characteristics were compared with particle image velocimetry(PIV). They were summarized on jet flow field and vortex structures,gas jet boundary expansion,nozzle axial velocity Attenuation law,the radial velocity distribution by means of experimental analysis and image processing. Experimental results show that: the jet boundary expansion linearly,its features are available to characterized by the size of the cone angle,cone angle decreases with increasing pressure,and significantly,the temperature has some influence too. Axial velocity inversely proportional to distance,the velocity impact area with jet distance increases,temperature increases makes the axial velocity corresponding increase under the same pressure,different jet section have similar velocity distribution.