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两相流系统中,流型会直接影响系统的摩擦阻力和传热等特性,而流型的转变过程会受到通道的形状和尺寸的影响.常温常压下,以空气和水为介质,对八种不同尺寸矩形通道中竖直向上泡状流向弹状流转变过程进行了研究.结果表明,矩形通道间隙大于2 mm时,随着通道水力直径的增大,泡状流向弹状流转换边界左移.在窄通道范围内,可采用Ishii(1977)提出的基于漂移流模型的判定准则计算流型转换边界;在常规矩形通道中,转换准则中的临界空泡份额与气泡初始尺寸有关,选用赵建福提出的方法计算临界空泡份额,转换边界预测结果与实验结果符合程度较好;在利用漂移流方法计算截面含气率时,对于窄矩形通道,分布系数可以用Ishii(1977)提出的方法计算,而对于常规矩形通道,分布系数为1.2.“,”Flow pattern transition always affect the frictional resistance and heat transfer in two-phase systems,whereas it itself is also affected by the shape or size of the channels.The transition from bubbly flow to slug flow in eight different rectangular channels was investigated under normal condition.The results shows that the transition boundary from bubbly flow to slug flow moves to left as the diameter increasing when the channel gap is smaller than 2 mm.The transition criteria can be predicted from the model from Ishii (1977) in narrow rectangular channels.While for common channels,the critical void fraction in the transition criteria is relevant to the size of bubbles in entrance,for which calculation method of Jianfu Zhao (2005) is proposed,leading to the predicted transition criteria with a good agreement against the experimental result.When using of drift-flux model,the distribution parameter C0 in channels is calculated with different forms,and the result shows that correction from Ishii (1977) can be used in narrow size of rectangular channels,while C0 remains to be 1.2 in common channels.