竖直圆管内空泡份额径向分布特性形成机制

Formation Mechanism of Radial Void Fraction Distribution of Bubbly Flow in A Vertical Circular Tube

在常温常压下，采用光纤探针测量方法对垂直上升大圆管中空气．水两相流动的空泡份额径向分布特性及形成机制进行研究。实验选用圆管直径为100mm，气相、液相折算速度的范围分别为0．004～0．053m／s和0．071-O．213m／s。结果表明空泡份额径向分布随着气．液流量的不同，呈现出“核峰”或“壁峰”型分布特点；通过分析气泡所受到的横向升力和壁面力，表明二者对气泡横向运动的综合作用是造成空泡份额径向分布呈现出“核峰”或“壁峰”型分布的主要原因。

The formation mechanism of radial void fraction distribution of gas-liquid two phase flow in a vertical circular tube was investigated experimentally by using an optical fiber probe under ambient temperature and pressure. Experiments were conducted in a tube with inner diameter of 100 ram, and with the gas and liquid superficial velocity covering the ranges of 0.0042-0.053 m.s~ and 0.071-0.213 m.sj, respectively. The results show that local void fraction shows a ＂core＂ or a ＂wall＂ peak distribution along the radius with different gas and liquid flow rates. The analysis of the wall force and lift force acting on a bubble shows that the two forces are of great importance in leading to a ＂core＂ or ＂wall＂ peak distribution of the void fraction due to their key role in determining the transverse movement of a bubble.