Distribution of local void fraction for subcooled boiling flow in rolling circular tube

doi:10.11949/j.issn.0438-1157.20151372

Abstract

Abstract:

Subcooled boiling flow exists in many technical applications of process and engineering such as nuclear reactors, steam generators and refrigeration systems. Accurate prediction of local void fraction is of significance for establishment of two-phase flow mathematical model and estimation of pressure loss and heat transfer capability. The radial local void distribution of subcooled boiling flow under rolling conditions was experimentally investigated by double-sensor optical probe, of which the transient local void fraction was obtained by periodical accumulation method. It showed that the local void distribution under rolling conditions exhibited a periodic variation, where the peak void fraction appeared in near-core region and near-wall region of the circular tube, and the largest amplitude of local void fluctuation existed in the near-wall region. Different from that under static conditions, the spatial distribution of local void fraction changed with the time within a rolling period. Furthermore, the period and amplitude rolling influence the distribution of local void fraction.

Key words: two-phase flow, subcooled boiling flow, voidage, optical probe, rolling condition, bubble

摘要：

过冷流动沸腾在核能、动力、化工等工业领域广泛存在,局部空泡分布特性的准确预测对构建两相流数理模型及两相流动压降和传热特性计算均具有重要意义。实验借助光学探针测量手段研究摇摆条件下圆管内过冷沸腾局部空泡分布特性,并提出多周期同相位叠加方法获得摇摆运动条件下局部瞬时空泡份额。实验结果表明:摇摆条件下圆管内局部空泡分布呈现周期性波动规律,摇摆条件下圆管轴心区及近壁区均会出现局部空泡份额峰值,且流道近壁区局部空泡份额波动幅度最大;与静止条件下不同,摇摆运动周期内过冷沸腾局部空泡份额空间分布形态随时间发生变化;摇摆周期和摇摆角度对过冷沸腾局部空泡分布特性也存在一定影响。

关键词: 两相流, 过冷沸腾, 空隙率, 光学探针, 摇摆条件, 气泡

CLC Number:

TK124

BAO Wei, CHEN Bingde, XU Jianjun, XIE Tianzhou, HUANG Yanping. Distribution of local void fraction for subcooled boiling flow in rolling circular tube[J]. CIESC Journal, 2016, 67(6): 2277-2283.

鲍伟, 陈炳德, 徐建军, 谢添舟, 黄彦平. 摇摆条件下圆管内过冷沸腾局部空泡时空分布特性[J]. 化工学报, 2016, 67(6): 2277-2283.

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