化工学报 ›› 2003, Vol. 54 ›› Issue (6): 749-753.

• 传递现象 • 上一篇    下一篇

信号奇异性的边缘检测小波对CHF和最小膜态沸腾起始点的检测

尚智; 贾斗南; 杨瑞昌   

  1. 清华大学热能工程系;西安交通大学核能系
  • 出版日期:2003-06-25 发布日期:2003-06-25

DETECTION OF CHF AND START POINT OF MINIMUM FILM BOILING WITH WAVELET FOR BOUNDARY DETECTION OF SIGNAL SINGULARITY

SHANG Zhi, JIA Dounan, YANG Ruichang   

  • Online:2003-06-25 Published:2003-06-25

摘要: 汽液两相流动的CHF(临界热流密度)和Tmin(最小膜态沸腾起始点)等特性点附近曲线存在转折,即在此点附近曲线的梯度要发生变化,从数学角度看这些点必然具备一定的奇异性.目前对于函数(信号)奇异性的检测方法主要是用小波变换实现的,由于小波分解具有良好的空间域和频率域的局部化特性,小波变换可以刻画出信号的变化规律以及对信号内奇异点的各种奇异性质进行检测和分析.对汽液两相流动中各传热特性点也可以用边缘检测小波变换去进行分析,并实现对它们的检测、定位和定量分析.通过对具体试验数据的边缘算子的检测证明了边缘检测小波完全可以用于对汽液两相流动的CHF和Tmin等特性点进行检测,并开创了一类新的汽液两相流动的试验研究方法.

关键词: 汽液两相流, 小波变换, 边缘检测, CHF, 最小膜态沸腾起始点

Abstract: There are kickpoints on the curves about critical heat flux (CHF) and start point of minimum film boiling (Tmin) of vapor liquid two phases flow. Changes of gradient occur round these kickpoints. There must be of singularity at the kickpoints in mathematics. Detection of signals can be obtained through wavelet translation, using the excellent local characteristics for space and frequency filed. The singularity and changes, which are hidden in signals, can be discovered by the characteristics of wavelet. Wavelets of boundary detection are used in vapor-liquid two phases flow for detecting CHF and Tmin. This wavelet analysis method can detect, orient and rate these points of two phases flow and is confirmed by the experiments results. This study initiates a new experimental method for vapor-liquid two phases flow.

Key words: 汽液两相流, 小波变换, 边缘检测, CHF, 最小膜态沸腾起始点