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逆环状流汽膜特征研究是当前国际上流动膜态沸腾的研究重点之一。设计并建立了一套实用的可视化研究实验回路,采用照相技术获得了加热条件下稳态逆环状谕膜态沸腾照片。就现有的资料,尚未见到稳态条件下水介质流动膜态沸腾可视化研究结果。本文论述了典型的逆环状流汽膜特征,认为Elias~(【1】9【2】)由瞬态实验结果提出的两区模型近似合理。在加热条件下至少存在类似Jarlais【3】的绝热模拟实验归纳的三种汽液交界面特征,即:不对称正弦波动界面、似静脉曲张型波动的对称交界面以及滚动波。在加热流动下不仅会发生液动力不稳定性引起的流型过渡,还可能出现因热力不稳定性引起的过渡。术文还讨论了质量流速、人口过冷度、平均加热热流、初始含汽量、以及系统压力等参数对汽膜特征的影响,并利用23组实验结果由最小二乘法拟合了一个等膜厚区膜厚经验参考式。
Research on the characteristics of reverse-flow steam film is one of the focuses of current international research on membrane boiling. A set of practical visualization experimental circuit was designed and established. The photosynthesis was obtained by photographic technique under the condition of heating. For the available data, the results of visualization of membrane boiling in aqueous media under steady-state conditions have not been observed yet. In this paper, the characteristics of a typical inverse annular flow steam membrane are discussed. It is considered that the Elias ~ (1, 9) [2] is approximately reasonable in the two-zone model proposed by the transient experimental results. There are at least three vapor-liquid interfaces characterized by adiabatic simulations similar to those of Jarlais [3] under heating conditions: the asymmetric sinusoidal interface, the symmetric interface that resembles varicose-type undulations, and the rolling wave. Under heating flow, not only flow pattern transition due to hydrodynamic instability occurs, but also transition due to thermal instability may occur. The paper also discussed the influence of mass flow rate, overcooling, mean heating heat flux, initial steam content, and system pressure on the characteristics of the vapor film. The results of the 23 groups of experiments were fitted by the least square method Thick film thickness experience reference.