矩形长宽比对射流中心线湍流特性的影响  

Statistical properties of turbulent free jets issuing from rectangular nozzles with different aspect ratios

作　　者：马梓然 徐敏义[1] 栾剑[1] 刘晓鹏[1] 赵飞飞[1] 

机构地区：[1]大连海事大学轮机工程学院,辽宁大连116026

出　　处：《实验流体力学》2017年第1期54-61,共8页Journal of Experiments in Fluid Mechanics

基　　金：国家自然科学基金(51506019);辽宁省自然科学基金(2012025012)

摘　　要：采用热线风速仪技术,测量了在出口雷诺数15,000条件下的不同长宽比(AR=1~15)矩形射流中心线速度场。主要分析了矩形射流中心线上平均速度、频谱、湍流尺度等变化规律。结果表明:随着长宽比的增加,射流的脉动速度和湍流度在出口之后会显著增强,反映了卷吸周围流体能力显著增强。随着射流向下游发展(x/De>30),不同长宽比的矩形射流湍流能谱、概率密度函数、湍流尺度等统计量逐渐趋近于圆形射流规律,这是由于射流演化遵循动量向周围流体更高效传递的原理。This paper reports the experimental investigation of the turbulence characteristics of the free air jets issuing from rectangular orifices with different aspect ratios（AR=1-15）.The velocity was measured by a hot-wire anemometer with the exiting Reynolds number（Re）being15,000 for all jets,based on the equivalent diameter of the rectangular orifices.This paper mainly analyzes the evolution of centerline average velocity,frequency spectrum,turbulence scale along the centerline of rectangular jets.The results show that the centerline mean velocity decays faster and the turbulence intensity grows higher as ARincreases.With jet flows developing downstream（x/De〉30）,the turbulence energy spectrum,probability density function and turbulence length scales of rectangular jets approach to those of circular jets.The principle for this phenomenon is that the momentum from the jet always spreads into still surroundings in more efficient way.

关 键 词：矩形射流 湍流度 频谱 湍流尺度 

分 类 号：O358[理学—流体力学]