并联蒸发管内两相流密度波型脉动线性分相模型

Linear Phase-separation Model for the Two-phase Flow Density-wave Type Pulsations in Parallel-connected Evaporating Tubes

两相流密度波型脉动理论分析方法可以分为两大类:一类是数值解析法,另一类是近似分析法。数值分析法已经有很多学者进行了大量研究,而近似分析法研究相对少一些,特别是运用系统控制原理的方法来分析两相流密度波型脉动就更少,本文运用系统控制原理的方法来研究两相流密度波型脉动,提出了描述并联沸腾管内两相流密度波型脉动的线性分相模型,导出了描述系统稳定性的状态空间表达式,计算了质量流速、热负荷和系统压力的变化对系统特征方程式的特征根的影响。结果表明:各个参数对密度波型脉动界限值的影响规律与实验值是一致的。

Methods for the theoretical analysis of two-phase flow density-wave type pulsations can be divided into two categories: 1. numerical analysis method and 2. approximate analysis method. Many academics have conducted a huge amount of research on the first method, while relatively little research has been undertaken on the second method. In particular, even less research by using the method of system control theory has been conducted to analyze the two-phase flow density-wave type pulsations. In view of this, the authors have employed the method of system control theory to study the above-mentioned pulsations, proposing a linear phase-separation model for describing the two-phase flow density-wave type pulsations in parallel-connected boiling tubes. A status-space expression for describing system stability has been derived. Calculations were performed to determine the impact of the variation of mass flow velocity, thermal load and system pressure on the characteristic root of a system characteristic equation. The results of the calculation indicate that the law governing the impact of various parameters on the density-wave type pulsation limit values is in agreement with that of the experimental values.