T型管中冷热流体混合过程热波动大涡模拟

Large Eddy Simulation of Hot and Cold Fluids Mixing in a T-Junction for Prediction of Thermal Fluctuations

在FLUENT平台上,运用大涡模拟湍流模型及Smagorinsky-Lilly亚格子模型,对T型混合结构中的温度波动进行了模拟.获得了分别用于描述时均温度和温度波动强度的无量纲时均温度和无量纲均方根温度.分析了用于热疲劳分析和生命周期评价关键参数,即温度波动的功率谱密度函数.对不同条件下的混合过程进行了模拟,分析了不同Reynolds数Re和Richardson数Ri对混合过程和热波动的影响.

The temperature fluctuations in a mixing T-junction have been simulated on the FLU- ENT platform using the large eddy simulation （LES） turbulent flow model with a sub-grid scale Smagorinsky-LiUy model. The normalized mean and root mean square temperatures, which are used to describe the time-averaged temperature and temperature fluctuation intensity, were obtained, as well as velocity. The power spectral densities of temperature fluctuations, which are key parameters for thermal fatigue analysis and life time evaluation, were analyzed. The simulation results were consistent with experimental data published in the literature, which shows that the LES is reliable. Several mixing processes under different conditions were simulated in order to analyze the effects of varying Reynolds number （Re） and Richardson number （Ri） on the mixing course and thermal fluctuations.