Flow and heat transfer characteristics of falling water film on horizontal circular and non-circular cylinders  

作　　者：罗林聪 张冠敏 潘继红 田茂诚 

机构地区：[1]School of Energy and Power Engineering, Shandong University

出　　处：《Journal of Hydrodynamics》2013年第3期404-414,共11页水动力学研究与进展B辑（英文版）

基　　金：support by the Shandong Province Key Scientific and Technological Project (Grant No. 2008GG10007009);the Science and Technology Development Planning of Shandong Province (Grant No. 2012GGX10421)

摘　　要：This paper presents a two-dimensional CFD study of the falling film evaporation of horizontal tubes with different shapes applied in the seawater desalination. The flow and heat transfer characteristics of the falling water film on one circular tube and two non-circular shaped tubes, a drop-shaped tube and an oval-shaped tube, are analyzed, respectively. The Volume Of Fluid （VOF） method is employed to investigate the influence of the mass flow rate and the feeder height on the distribution of the film thickness and the heat transfer performance. The numerical results show that the minimum value of the film thickness appears approximately at the angular positions of 125~, 160~ and 170~ for the smooth circular, oval- and drop-shaped tubes, respectively.The film thickness grows with the increase of the mass flow rate and the decrease of the feeder height, while the variation pattern varies for different tubes. Moreover, compared with the circular tube, the drop- and oval-shaped tubes have a lower dimensionless temperature and a thinner thermal boundary layer, which means a better heat transfer performance. Finally, the numerical results correlate well with the experimental and predicted data in literature.This paper presents a two-dimensional CFD study of the falling film evaporation of horizontal tubes with different shapes applied in the seawater desalination. The flow and heat transfer characteristics of the falling water film on one circular tube and two non-circular shaped tubes, a drop-shaped tube and an oval-shaped tube, are analyzed, respectively. The Volume Of Fluid （VOF） method is employed to investigate the influence of the mass flow rate and the feeder height on the distribution of the film thickness and the heat transfer performance. The numerical results show that the minimum value of the film thickness appears approximately at the angular positions of 125~, 160~ and 170~ for the smooth circular, oval- and drop-shaped tubes, respectively.The film thickness grows with the increase of the mass flow rate and the decrease of the feeder height, while the variation pattern varies for different tubes. Moreover, compared with the circular tube, the drop- and oval-shaped tubes have a lower dimensionless temperature and a thinner thermal boundary layer, which means a better heat transfer performance. Finally, the numerical results correlate well with the experimental and predicted data in literature.

关 键 词：non-circular cylinder falling film numerical simulation heat transfer enhancement DESALINATION 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TU834.43[动力工程及工程热物理—热能工程]