低液流量下におけるチャーン流の流動特性 : 流体工学 , 流体機械
2001 年 67 巻 654 号 p. 356-363
詳細
2001 年 67 巻 654 号 p. 356-363
In the vertical upward gas-liquid two-phase flow, churn flow is a distinctive flow pattern that appears in the intermediate region between annular and slug flow. To clarify the flow characteristics of churn flow, simultaneous measurements of spatio-temporal characteristics of gas-liquid interface and pressure gradients are conducted at low liquid flow rate conditions. Flow reversal of the liquid film and large wave formation are found to be characteristic features in this regime. The decrease of gas flow rate makes the flow oscillation more violent, which induces a breakdown of the continuous gas core by bridging of the liquid film, and eventually leads to the flow pattern transition from churn to slug flow. The effect of flow structure of churn flow on the frictional pressure gradient is also investigated. It is found that the negative slope and the drastic decease in the frictional pressure gradient are attributable to the propagation of large wave and the formation of the developing slug flow, respectively.
