【摘要】 采用可视化方法对水的降膜流动过程进行了实验研究,考察了两异形管(蛋形管和滴形管)管间流型及其转变、降膜波长随Re数和管型的分布规律,并与圆管进行了对比分析。实验结果表明:各管的管间流型均随Re数的增大依次呈现滴状流、滴柱状流、柱状流、柱片状流和片状流;相较于圆管,两异形管的各流型更易在较低的Re数下获得,且流型较稳定。随着Re数增加和管间距S的降低,降膜波长呈减小趋势。两异形管的降膜波长较圆管的低,且蛋形管的流型转变Re数最低。更多还原

【Abstract】 The aim of the present study is to investigate the effect of the tube type,Reynolds number and intertube spacing on the falling film modes and dimensionless wavelength for oval- and drop-shaped tube by a visualization experimental study.Then,a comparison between circular tube and the two shaped tubes was conducted.The experimental results show that the flow modes between the tubes can be observed:discrete droplets,drop-jet,liquid jet,jet-sheet,or continuous liquid sheet for all the test tubes with the increase of Reynolds number.Compared with the circular tube,the more stable flow modes of the shaped tubes can be obtain at a lower Reynolds number.Under the conditions of this study,the falling wavelength decreases with the increase of Reynolds number and the decrease of intertube spacing.The study found that the falling wavelength of the shaped tubes is smaller than that of the circular tube and the Reynolds number of mode transition of the oval-shaped tube is smallest.更多还原