【作者】 曹夏昕；

【导师】 阎昌琪；

【作者基本信息】 哈尔滨工程大学 ， 核能科学与工程， 2006， 博士

【摘要】 当不同组分的两相通过管道时，会形成多种具有不同流动特性的流型。流型的改变除了受设备中管道的结构、布置方式以及加热状态等影响外，还与设备是否处于静止环境中有关。因此，本论文的主要目的就是借助于实验和理论分析来研究摇摆对竖直管内气—液两相流型变化的影响。实验研究主要是在常温常压下的摇摆台架上进行，试验段为透明的有机玻璃管，空气和水作为流动工质同向通过试验段形成不同形状的流型。实验中观察到，摇摆使得试验段内的流型呈现周期变化的特征。借助压差波动的时域特征及可视化观察的方法，本文确定了泡状流和环状流的产生点；利用分相流模型，通过定性分析确定管内压降变化的转折点即为弹状流向搅混流转变的产生点。通过对实验数据的分析发现，管径、摇摆周期和摇摆角度对流型存在的区域有明显影响；在不同的流型下，平均截面含气率随着管径、质量流速、摇摆角度和摇摆周期的改变而发生变化。在实验研究的基础上，本文给出摇摆状态下泡状流、弹状流、搅混流平均空泡份额计算式。另外，根据混合相-单相并流模型，对摇摆状态下环状流平均空泡份额的计算值与实验值进行对比，发现该模型能够很好地预测摇摆状态下环状流平均空泡份额。通过对单相水在摇摆状态下的运动分析，在结合雷诺数、摇摆角度和摇摆周期对单相摩阻系数变化影响的基础上，本文提出了一个新的摇摆条件下单相水流经光滑管的摩阻系数半经验关系式。在此基础上，结合不同的流型特征，分别给出弹状流、泡状流和环状流的摩阻压降计算式，并与实验值进行了对比，计算值与实验值符合较好。在充分考虑摇摆附加惯性力的影响的条件下，本文对摇摆状态下气液两相流型之间的转变机理展开分析，首次提出了摇摆状态下弹状流向泡状流、弹状流向搅混流以及搅混流向环状流的转变准则关系式，并对预测计算值和实验值进行了对比，结果符合较好。考虑到强制循环下，气液两相流速基本不受摇摆条件的影响，因此，本文依然采用气相和液相折算流速作为摇摆状态下气液两相流型图的横坐标和纵坐标，绘出摇摆状态下的气液两相流型图，为工程应用提供一定的参考。更多还原

【Abstract】 A variety of flow patterns with different flow characteristic could exist when co-current gas-liquid containing different component flowed through tubes. The characteristic of flow patterns not only depended on the gas and liquid flow rates, pipe structure, pipe layout et al, but also was affected by the state if the device was under the stable condition. So, this dissertation aimed at studying experimentally and theoretically the effect of rolling condition on gas-liquid flow pattern properties in vertical tubes.The experimental research was mainly carried out in a rolling test facility at atmospheric pressure and temperature, and the test section was glass tube, through which the air and water co-current flow and form different flow patterns. During the experiments, it was observed that flow patterns periodically changed during the rolling motion. Depending on pressure differential fluctuation method and visual observation, the onset of bubble flow and annular flow could be decided; Using separated two-phase flow model to make qualitative analysis, and the results showed that the turning point of inside pressure difference curve was just the point where the churn flow took place.Through the analysis of experimental data, it was found that the area of flow pattern was obviously influenced by tube diameter, rolling period and rolling angle, and average void fraction also changed with the vary of mass flow rate, tube diameter, rolling period and rolling angle. Based on the experimental data, the average void fraction correlations of bubble flow, slug flow and churn flow were fitted. Besides, by comparing the average void fraction calculation and experimental data of annular flow, it was found that mixture-single phase model could well predict the average void fraction of annular flow under rolling condition. Based on the analysis of single phase water with rolling motion and experimental research on the effects of Reynolds number, rolling angle and rolling period on single-phase frictional coefficient, a new single-phase frictional coefficient semi-empirical correlation for rolling condition had been proposed. Using this correlation, frictional pressured drop correlations of slug flow, bubble flow and annular flow were also developed, and the calculated results were in good agreement with experimental data, respectively. Moreover, the transition mechanisms between flow patterns under rolling condition were individually analyzed. The Transition criterion correlations of slug flow to bubble flow, slug flow to churn flow and churn flow to annular flow were firstly proposed with the consideration of additional inertia action. By comparing the experimental data, these Transition criterion correlations could be used to predict the transition boundary between flow patterns under rolling condition.Owing to the two-phase flow rate in forced circulation was not changed by the rolling motion, the gas superficial velocity and liquid superficial velocity were chose to be the horizontal coordinate and longitudinal coordinate, and the flow pattern map under rolling condition was drawn, which was hoped to provide some reference in engineering.更多还原