Direct contact condensation of steam bubbles in water at high pressure
Direct contact condensation of steam bubbles in water at high pressure
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DOI：
10.1016/0017-9310(77)90158-2
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发表时间：
1977-04
影响因子：
5.2
通讯作者：
G. Brucker;E. Sparrow
中科院分区：
文献类型：
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作者：
G. Brucker;E. Sparrow
对饱和蒸汽气泡在静止过冷水环境中的直接接触凝结进行了实验研究。实验的压力范围为10.3至62.1巴（150-900磅平方英寸），过冷温度为15至100° C，初始气泡直径约为3 mm。高速运动图像的数据简化是基于逐帧分析，其中以数字形式记录气泡周界的坐标，并随后进行处理以产生关于气泡破裂历史和传热系数的定量信息。这些照片显示，气泡在坍缩过程中的形状是从球形到半球形，再到椭球形，最后再到球形，最后坍缩;寿命短的气泡坍缩成椭球形。随着压力的增加和温差的减小，塌陷时间和塌陷高度增加。气泡的上升速度基本恒定，总体范围为15- 22 cm/s。平均传热系数约为10 4 W/m2·° C（1750 Btu/h· ft 2·° F），随压力和温差变化不大。瞬时传热系数与平均系数没有明显差异。
Experiments have been carried out to investigate direct contact condensation of saturated steam bubbles introduced into a quiescent subcooled water environment. The experiments were performed for a range of pressures from 10.3 to 62.1 bar (150–900 lb in 2), for subcooling from 15 to 100° C, and for initial bubble diameters of about 3mm. The data reduction of high speed motion pictures was based on a frame by frame analysis wherein the coordinates of the bubble perimeter were recorded in digital form and subsequently processed to yield quantitative information about the bubble collapse history and heat-transfer coefficient. The photographs showed that the successive shapes of the bubbles during their collapse histories proceeded from a sphere to a hemisphere to an ellipsoid to a sphere to collapse; short-lived bubbles collapsed as ellipsoids. The time to collapse and the height to collapse increased with increasing pressure and with decreasing temperature difference. The rise velocities of the bubbles were essentially constant, with an overall range of 15–22cm/s. The average heat-transfer coefficients were on the order of 10 4 W/m 2·° C (1750 Btu/h· ft 2·° F), with only modest variations with pressure level and temperature difference. The instantaneous heat-transfer coefficients did not differ appreciably from the average coefficients.