鼓泡塔反应器英文文献和中文翻译(3)

density and operating pressure on stable bubble sizes is
closely connected, since pressure mainly aﬀects gas
density. Idogawa et al. and Wilkinson [6,22] investigated
gas/water systems for diﬀerent gases and variable pres-
sure and found decreased bubble sizes for increasing gas
density. Wilkinson explained this behavior with in-
creased bubble breakage. Other investigators found the
same, but at increased pressure this eﬀect was found to
be less pronounced [4]. Coalescence investigations of
Sagert and Quinn [19,20] conﬁrmed this trend. For in-
creased pressure they observed increased coalescence
times for CO2,H2S, N2O and alkane bubble pairs in
water, hence coalescence is declined.
To study the inﬂuence of pressure on bubble size
distributions, several experiments with nitrogen bubbles
in water were performed.
• In a stagnant coalescence experiment two nitrogen
bubbles emerging slowly from two opposing nozzles
were brought into contact at 1 and 45 bar. The co-
alescence time increased only slightly with pressure.
• In a dynamic coalescence experiment a rising bubble
could collide with a second one, attached to a nozzle.
In this experiment the coalescence probability de-
creased signiﬁcantly with increasing pressure.
• A sequence of single bubbles was detached from a
single nozzle and its subsequent breakage was re-
corded (Fig. 3). This experiment showed an increase
of breakage probability with increasing pressure.
• Bubble swarms were generated using diﬀerent spar-
gers and the development of the mean Sauter diame-
ter was recorded with increasing distance from the
sparger (Fig. 4). These experiments showed an in-
crease of the Sauter diameter towards a stable bubble
diameter which is decreased with increasing pressure.
This leads to the following interpretation: Pressure
increase leads to an increase in bubble breakage due to
the increase in gas density, caused by the larger inertia of
the gas in the ﬂuctuating bubble. This is clearly shown 摘要：气液过程的设计需要有对气泡尺寸分布详细的知识，因为它决定着传质。在本文中，讨论了操作条件与气体及液相的物理性质对在最初和在最后（“稳定的”)气泡大小的影响。测量在一个实验室规模的用来对不同液体对氮气喷射的鼓泡塔中进行，它的压力高达50bars而温度高达175摄氏度。气泡尺寸分布取决于图像处理。
气泡在不断减小的表面张力、不断上升的气体密度和不断下降的液体黏度的作用下趋向于变得更小。论文网如果忽略蒸发作用的话，这导致了稳定的气泡尺寸在增强的压力和升高的温度的作用下的减少。含水的和有机的液体中的杂质能通过抑制聚结来极大地影响到气泡尺寸。对于这样一个系统，塔中的气泡尺寸分布主要依靠于主要的气泡尺寸。而主要的气泡尺寸又取决于分布器的设计。
关键词：气泡破裂；鼓泡塔；气泡形成；聚集；高压与高温；稳定的索特直径鼓泡塔反应器英文文献和中文翻译(3):http://www.youerw.com/fanyi/lunwen_17276.html