摘要
采用k-ε双方程模型研究存在浮力的传热流动问题时,数学模型中的参数-紊动普朗特数的取值大小对模拟计算的流速和温度分布存在不同程度的影响.本文在已有实验推荐的取值范围的基础上,采用圆柱轴对称坐标系下的k-ε模型,研究了不同紊动普朗特数取值对数值模拟结果逼近真实值的影响程度.研究得到紊动普朗特数取值的变化对轴线流速的大小和分布影响很小,即数值模拟得到的轴线上的流速仍能很好的预报出实验或真实流速值;但对温度分布影响较大,且紊动普朗特数的取值越小,数值模拟出来的轴线上的温度值与真实值相比偏小.得出了紊动普朗特数在大小不同雷诺数下的合理取值变化范围,其结论对采用数学模型研究各种复杂流动具有指导意义.
In the study of heat flow with buoyancy by using a k-ε model, the value of Prandtl number can affect the computed distributions of velocity and temperature. Based on the value range for Prandtl number suggested by experiments, how different values of Prandtl number affecting the simulated results was studied qualitatively by using a k-ε model under axisymmetric coordinate. Results indicated that the value of Prandtl number had little effect on axial velocities and the real velocity value can be well predicted by the model with different values of Prandtl number. However, it affected the distribution of temperature, and a small value of Prandtl number tended to produce an axial temperature smaller than the real value. The reasonable value ranges of turbulent Prandtl number for different Reynold numbers were suggested. The conclusions are valuable for the study of various complicated flows using mathematical models.
出处
《应用基础与工程科学学报》
EI
CSCD
2006年第3期435-443,共9页
Journal of Basic Science and Engineering
基金
国家自然科学创新研究群体科学基金资助项目(50221903)
关键词
浮力射流
数学模型
紊动普朗特数
轴对称坐标系
buoyant jet
mathematical model
turbulent Prandtl number
axisymmetric coordinate
