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本文归纳了几年来对两相流体不稳定研究的理论和试验成果,论证并说明了在各种沸腾流道系统中通常发生的三种不同类型的两相流体脉动,即密度波型,压降型和热力型脉动。首先概述两相流不稳定的分类,即三种两相流体脉动的区别和它们的机理。自从50年代原子反应堆商业化以来,西方国家开始研究不稳定性问题,接着苏联和中国也进行了研究。本文叙述了在单流道、双流道、交叉连接的双流道,四平行流道和四交叉平行流道向上流动系统中暂态的和持续的不稳定性的实验结果。指出了热流量变化,进口欠热,流量,进口和出口阻力的影响。同时包括了在垂直的单流道中强化传热对两相流不稳定的影响。综述了以均相两相流和两相热力平衡为假设的数学模型,用来预报在单流道中强迫对流沸腾向上两相流动稳定的和暂态的特性,并叙述了这些解的结果。提出了在单流道向上流动的沸腾系统中两个不同的两相流模型,即用来预报压降型不稳定界限的常参数均相流动模型和用来预报密度波不稳定界限的变参数漂流模型,并列出了一些解。
This paper summarizes the theoretical and experimental results of the studies on the instability of two-phase fluids over the past few years, and demonstrates and demonstrates the three different types of two-phase fluid pulsations that commonly occur in various fluidic flow channel systems, namely, the density wave pattern, Type and thermal pulsation. First, an overview of the two-phase flow instability classification, namely the difference between the three two-phase fluid pulsations and their mechanism. Since the commercialization of atomic reactors in the 1950s, Western countries began to study the issue of instability, followed by the Soviet Union and China. This paper describes the experimental results of transient and persistent instabilities in single-channel, dual-channel, cross-linked dual-channel, quadruple parallel and quadruple parallel- channel upflow systems. The effects of changes in heat flux, under-heating of the inlets, flow rates, import and export resistance were pointed out. The effect of enhanced heat transfer on the instability of two-phase flow in a vertical single-flow channel is also included. A mathematical model based on the assumption of homogeneous two-phase flow and two-phase thermal equilibrium is presented to predict the steady-state and transient behavior of the forced convection boiling upward two-phase flow in a single channel. The results of these solutions are also presented. Two different two-phase flow models in a single-channel upflow boiling system are proposed, that is, a constant-parameter homogeneous flow model for predicting the pressure drop-type instability limit and a variable parameter for predicting the instability limit of the density wave Drifting model and lists some solutions.