Liquid film behavior in annular two-phase flow under flow oscillation conditions
Liquid film behavior in annular two-phase flow under flow oscillation conditions
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DOI：
10.1016/j.ijheatmasstransfer.2009.11.024
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发表时间：
2010-02
影响因子：
5.2
通讯作者：
T. Okawa;T. Goto;Yosuke Yamagoe
中科院分区：
文献类型：
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作者：
T. Okawa;T. Goto;Yosuke Yamagoe
实验研究了入口流量正弦强迫振荡对汽液两相环形流局部液膜厚度和大波通过频率随时间变化的影响。液膜厚度随进口流量的变化呈同周期振荡。随着入口流量振荡周期的增加，薄膜区的平均膜厚逐渐减小并趋于一个渐近值。这一结果与文献报道的在流动振荡条件下发生液膜干涸的实验结果一致。因此认为，从厚膜区域到薄膜区域的轴向液体传输减轻了由流动振荡引起的临界热通量的降低。还发现，在薄膜区域中的波频率随着振荡周期的减小而增加。这一观察结果表明，扰动波有助于液体传输的增强，从而与液膜干燥在流动振荡条件下的临界热通量。
Experiments were carried out to investigate the effects of sinusoidal forced oscillation of the inlet flow rate on the time variations of local liquid film thickness and the frequencies of large wave’s passing in steam–water annular two-phase flows. The liquid film thickness oscillated with the same period as the inlet flow rate. The mean film thickness in the thin film regions decreased and approached to an asymptotic value with an increase in the oscillation period of the inlet flow rate. This result was consistent with the experimental results of the occurrence of liquid film dryout under flow oscillation conditions reported in the literature. It was hence considered that the axial liquid transport from the thick to thin film regions mitigates the reduction of the critical heat flux caused by the flow oscillation. It was also found that the wave frequency in the thin film region increased with a decrease in the oscillation period. This observation suggested that the disturbance waves contribute to the enhancements of the liquid transport and consequently the critical heat flux associated with the liquid film dryout under flow oscillation conditions.