鸭嘴阀扩散器卷吸特性研究

对同向流动环境中的水平DBV射流的掺混特性进行了一系列试验研究,对不同试验组次下的时均速度分量、射流边界、射流动量、紊动强度、雷诺应力和射流卷吸参量做了研究.研究结果表明：按时均中心线流速衰减规律,可将流动划分为3个区域,每个区域有其自身特定的指数衰减率;当x/D＞1.5,除主轴平面内的紊动应力以外,时均速度,紊动强度,雷诺应力出现自相似;轴变换发生在x/D＝1～1.5附近;平均稀释度和无量纲的沿程距离之间存在线性关系,相比于具有相同名义直径的同向流动环境中的圆射流,在相同排放流量条件下,DBV射流具有更好的稀释效果.

Mass entrainment in a duckbill valve jet

A series of experiments were performed to study the mixing characteristics of horizontal DBV jets in a coflow.Some parameters,including the mean velocity components,jet boundary,jet momentum,turbulence intensity,Reynold stress,and jet entrainment,were studied under different experimental conditions.The experimental results indicate that the decay of mean axial velocity can be divided into three regions,and each region has its own regularity of exponential decay.When x/D>1.5,the mean velocity,turbulence intensity,and Reynold stress show the characteristic of self-similarity;the axis switching occurs in the range of x/D=1-1.5;there is a linear relationship between the average dilution and dimensionless downstream distance;DBV jet has better effect of dilution as compared with the round jet of the same nominal diameter in coflows under the same volume of discharge.