双探头光学探针识别受热工况两相流流型的基本方法研究

Basic Methods of Two-phase Flow Regimes Identification by Dual-sensor Optical Probe in Heated State

由于流型识别手段受到限制,目前常用的流型图以及流型转变判据,都是在绝热工况下根据实验得到的;关于受热工况两相流流型还没有足够的实验数据。光学探针的运用为受热工况两相流流型的研究提供了有力的测量手段。本文对双探头光学探针4种流型识别的基本方法进行了研究,包括探针原始电平信号概率密度函数(PDF)分析识别流型、信号时序波形识别流型、空间波形识别流型以及汽泡尺寸PDF分析识别流型。研究结果表明,汽泡贯穿弦长PDF分析可得出满意的流型识别结果。

Two-phase flow regimes have significant effect on the transport characteristics of mass, momentum and energy, therefore, identification of two-phase regimes becomes one of the most fundamental problems in two-phase flow, and many identification methods have been developed. However, the flow regimes maps and transition criterions in common use, presently, are largely based on the experimental results in adiabatic flow due to the limit of flow regimes identification method, and the experimental results in heated state are still extremely limited. The appliance of optical probe is helpful for the flow regimes identification in heated tubes. Four identification methods by dual-sensor optical probe, including the probability density function (PDF) of original signal voltage, time-domain wave form, space-domain wave form and bubble size analysis, were investigated in this paper. It is demonstrated that bubble size analysis is the best one.