论文部分内容阅读
利用标准k-ε模型结合脉动燃烧器尾管的实验参数进行湍流脉动流动与换热的数值模拟,通过修正模型内的冯·卡门常数建立适用于实验条件下的脉动流动的湍流计算模型,并研究脉动湍流中压力振幅和频率对湍流流动和换热特性的影响。研究发现:符合实验条件下的冯·卡门常数范围为0.48～0.52;脉动瞬时截面上的速度在靠近壁面附近出现峰值且速度变化较大;速度与温度分布呈周期性变化;压力振幅越大,速度和温度波动范围就越大,频率越大,速度和温度的波动范围则越小;壁面摩擦系数随着压力振幅的增加而减小,随着频率的增加而增大;壁面平均对流换热系数随压力振幅的增加而增大,随频率的增加而减小。
The standard k-ε model was used to simulate the turbulent flow and heat transfer in the pulsating combustor liner. The von Karman constant in the model was used to establish the turbulent model for the pulsating flow under experimental conditions. The effect of pressure amplitude and frequency on turbulent flow and heat transfer in pulsating turbulent flow is studied. The results show that the von Karman constant under the experimental conditions ranges from 0.48 to 0.52. The velocity at instantaneous section of pulsation peaks near the wall and the velocity changes greatly. The distribution of velocity and temperature changes cyclically. The larger the pressure amplitude, The greater the range of velocity and temperature fluctuations, the greater the frequency, the smaller the range of velocity and temperature fluctuations; the friction coefficient of wall decreases with the increase of pressure amplitude, and increases with the increase of frequency; the average wall convection heat transfer The coefficient increases with the increase of pressure amplitude and decreases with the increase of frequency.