The T-junction has been extensively employed in nuclear power plant systems. To ensure the normal operation of nuclear power plant, the onset point of T-junction liquid entrainment requires in-depth studies. Existing studies have been conducted on the onset point of liquid entrainment, whereas most of them are for small branch pipes. This study primarily discussed the onset law of large branch pipe. Moreover, the effects of branch angle and size on the onset point of liquid entrainment were analyzed by comparing it with other branch pipe sizes in this study. This study demonstrated that the effect of branch angle on the onset point of entrainment complies with that of other sizes, i.e., because that the decrease in the inertial force in the vertical direction acting on the liquid phase by the gas phase with the decrease in the angle, hence, the onset requires larger Fr_g under the identical h_bwith the decrease in the angle between the branch pipe and the horizontal direction. Moreover, by comparing the onset point law of liquid entrainment exhibiting different branch pipe sizes, the effect of branch pipe size on the onset was reported in this study that the smaller branch pipe requires the greater gas velocity in the presence of onset. We found that there is different flow resistance of different sizes of branch pipe, small branch has larger flow resistance, in order to remedy the flow resistance, the gas dynamic head decreases, thereby causing the Bernoulli effect weaker; the onset of liquid entrainment requires larger V_3g.

T型结已广泛用于核电站系统中。为了确保核电站的正常运行，T型结液体夹带的起始点需要深入研究。已经对液体夹带的起始点进行了现有研究，而大多数研究是针对小型支管的。本研究主要讨论了大型支管的发病规律。此外，通过与本研究中的其他支管尺寸进行比较，分析了支管角度和尺寸对夹带起始点的影响。这项研究表明，支流角对夹带开始点的影响与其他尺寸的影响相符，即，由于垂直方向上的惯性力的减小，气相作用于液相，而夹杂物的减小，则减小了夹角。因此，角度r_G 在相同的情况下 H_b支管与水平方向之间的夹角减小。此外，通过比较表现出不同支管尺寸的液体夹带的起始点定律，本研究报道了支管尺寸对起始的影响，在存在起始的情况下，较小的支管需要较大的气体速度。我们发现，不同尺寸的支管存在不同的流阻，小支流的流阻较大，为弥补流阻，气体动力扬程减小，从而导致伯努利效应减弱。液体夹带的发作需要更大V_3克。