摘要
本文研究雷诺数(Re)对圆形渐缩喷嘴湍流射流的影响.实验在射流出口雷诺数为Re=4050—20100的范围内进行,分别测量了射流出口、中心线的平均及湍流流场以及部分径向剖面速度分布.所有测量均采用单热线恒温热线风速仪进行高频采样,所测流场范围在轴向上为0—30d(这里d为射流出口直径).虽然出口速度分布均为"平顶帽"形,但测量结果依然反映出Re对射流出口以及下游流场有强烈的影响.当Re小于临界值(～10000)时,平均速度场与脉动速度场均对Re有强烈依赖,大于临界值后则影响甚微.势核区长度、远场区速度衰减率及扩散率均与Re相关.
The present study systematically investigates by experiment the influence of Reynolds number （Re） on a turbulent jet issuing from a smoothly-contracting round nozzle. Measurements were performed for seven Reynolds numbers varying from Re = 4,050 to Re = 20,100 using single hot-wire anemometry and over an axial distance of 30 nozzle exit diameters. Although all the exit velocity profiles are of＂top-hat＂shape,these measurements reveal significant dependence on Re of the exit and downstream flows. The effect of Re on both the mean and turbulent fields is substantial for Re 10,000 and becomes weak beyond Re = 10,000. The length of the jet’s potential core and the far-field rates of decay and spread all depend significantly on Re.
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2010年第9期6331-6338,共8页
Acta Physica Sinica
基金
国家高技术研究发展计划(863)项目(批准号:2007AA05Z300)资助的课题~~
关键词
雷诺数
圆形射流
热线风速仪
Reynolds number
round jet
hot wire anemometer
