摘要
超临界流体的真实流体效应显著,密度随压力、温度发生剧烈变化,造成流场强烈的可压缩效应。本文采用直接数值模拟方法研究了超临界压力下的槽道湍流,求解低马赫数条件下的可压缩N-S方程。槽道内最大密度比为16,高于现有直接数值模拟研究。分析了超临界流体湍流的统计特性,发现由于Morkovin假设失效,密度脉动改变雷诺应力平衡,流向脉动速度具有较高的偏度及间歇性,流向速度脉动的湍动能谱和二阶结构函数在惯性子区分别具有-1次方、1/3次方标度律,附着涡假设仍然成立。
The real fluid effects are significant at supercritical pressure,the density of supercritical fluids vary drastically with temperature.In this paper,we investigate the channel flows at supercritical pressure by solving the compressible Navier-Stokes equation under low-Mach assumption using direct numerical simulations(DNS).The maximum density ratio in the channel reaches 16,which is higher than that in the existing DNS studies.The statistical properties of supercritical fluids are analyzed.It is found that the density fluctuations alter the stress balance due to the invalid of Morkovin’s hypothesis.Comparing to the incompressible flows,the stream-wise fluctuating velocity has higher skewness and intermittency.The energy spectra and second-order structural function have scaling laws of-1 and-1/3 power in the inertial sub-range,respectively,implying the existence of the attached eddies.
作者
李方博
裴斌斌
白博峰
LI Fangbo;PEI Binbin;BAI Bofeng(State Key Laboratory of Multiphase Flow in Power Engineering,Xi'an Jiaotong University,Xi'an 710049,China)
出处
《工程热物理学报》
EI
CAS
CSCD
北大核心
2022年第12期3325-3330,共6页
Journal of Engineering Thermophysics
基金
国家自然科学基金基础科学中心项目(No.51888103)
华能集团能源安全专项科技项目(No.HNKJ20-H87)。
关键词
可压缩效应
超临界流体
槽道湍流
统计特性
compressible effects
supercritical fluids
channel flow
statistics
