摘要
对同轴射流的流动及其冲击传热特性进行了数值模拟研究.研究中采用了四种同轴射流模型,它们分别由不同直径比或不同内套管长度构成,对三个Re数下同轴自由射流流场发展和演变的特征进行了模拟.研究表明,由于同轴内套管的存在,在出口处速度沿径向的分布呈现双峰形状,双峰会随着离开出口距离的增加而消失.直径比对速度分布影响较大,但离开出口足够远后,射流速度分布就不受喷嘴结构参数和流动雷诺数的影响.同轴射流冲击传热时,直径比d/D=0.53的同轴射流在整个平板上都比普通圆柱射流有更好的强化传热效果;在冲击驻点附近,传热性能受同轴射流的直径比影响较大.
The flow field development of a co axial jet and its impinging heat transfer characteristics were studied by numerical simulation. Four cases of co axial nozzles which were formed by different diameter ratios or different lengths of the inner pipe were used. The flow field development of the co axial free jets at three Reynolds numbers was numerically studied. The results showed that the velocity profile at the jet exit was discontinuous because of the intrusive presence of the walls of pipes in the co axial nozzle. These intrusions caused a double-humped velocity profile which disappeared with the increased downstream distance from the jet exit. The velocity profile was greatly affected by the diameter ratio. However, the velocity profile of the jet was almost independent of the geometrical parameters and the Reynolds number at a large distance from the jet exit. It is found that a co axial impinging jet at d/D 0. 53 yields higher heat transfer performance than a single jet over the whole plate. It is also shown that the impinging heat transfer around the stagnation point is greatly influenced by the parameter of the diameter ratio.
作者
徐志超
周静伟
耿丽萍
XU Zhichao;ZHOU Jingwei;GENG Liping(College o~ Metrology and Measurement Engineering,China Jiliang University,Hangzhou 310018,China)
出处
《中国计量大学学报》
2018年第2期128-135,共8页
Journal of China University of Metrology
基金
浙江省自然科学基金资助项目(No.LY15E060005)
关键词
同轴射流
流场
冲击传热
数值模拟
co axial jet
flow field
impinging heat transfer
numerical simulation
