CFD Simulation of Falling Film Flow Characteristics outside a Horizontal Tube
- 作者：Jinbo ChenQinggang QiuXiaoqi Yin
- 会议时间：2011-06-01
- 关键词：desalination ; horizontal tube ; two-phase flow ; film thickness ; numerical simulation
- 作者单位：School of Energy and Power Engineering, Dalian University ofTechnology, Dalian, 116024, P R China
- 母体文献：2011全国非常规水源利用技术研讨会论文集
- 会议名称：2011全国非常规水源利用技术研讨会
- 会议地点：青岛
- 主办单位：水利部
- 语种：chi
摘要
Numericcal investigation was performed to predict the film characteristic outside the tube in Horizontal-tube Falling Film Evaporator for Seawater Desalination.A physical model for numerical simulation was developed.The temporal change characteristics of film flow process and the film thickness distribution outside a horizontal tube were studied and the effects of liquid flow rate and liquid feeder height on the film thickness were also presented.The numerical results were compared with that of the empirical equation for calculating the falling film thickness and the experimental data attained under the same condition,the agreements between them were reasonable.The results show that wave behavior generates on the interface of a thin liquid film falling down an circumferential wall and fluctuations change irregularly over time; The film thickness decreases with the increases of liquid distribution height.The film thickness increases with the increases of liquid flow rate,but when the fluid flow density decreases to a certain value,the local dryout spot on the surface of the tube would occur.The film thickness decreases from the top of the tube firstly and then increases around the perimeter of the cylinder; The minimal values of the film thickness tend to locate at different angular position of 90°- 120° under different conditions,and the angular position of the thinner film may be the main position for dryout detection.