汽泡滑移现象及质量流速和热流密度对汽泡滑移生长的影响

Bubble Sliding Growth Phenomena and Mass Velocity and Heat Flux Effect on Sliding Bubble Growth

以去离子水为工质,对较高系统压力下竖直矩形窄流道内的汽泡生长特性进行可视化研究。由于单位体积潜热的提高,系统压力升高将抑制汽泡的生长,使得在相同生长时间内汽泡的尺寸大幅减小;随着系统压力升高,汽泡在核化点处的生长时间会明显地缩短。压力较高时,汽泡生长主要是在滑移过程中进行,滑移过程中,会间歇性地离开又再附上加热壁面;汽泡的滑移生长并不会随着质量流速或热流密度的变化而发生单调性地变化。

A visual experiment is carried out with water as working fluid at higher system pressure to in-vestigate the bubble growth in vertical narrow channel in this paper.It is found that the bubble growth is sig-nificantly restrained with the increasing of system pressure,resulting in obviously decrease in bubble size within the same growth time.Also the bubble growth time at nucleation point will be shortened notably with higher system pressure.The main bubble growing period is during bubble sliding,and the bubble will lift off and return to the heating wall periodically.Growth of sliding bubble would not be affected by mass flux and heat flux monotonously.