Three-dimensional Numerical Study On Heat Transfer And Flow Characteristics Of Horizontal Tube

The flow and heat transfer characteristics of the horizontal pipe falling film are the key to the performance of the heat transfer system.The distribution of liquid film thickness of horizontal pipe,the change of flow pattern between horizontal pipe and the arrangement of heat exchange pipe all directly influence the performance of the whole heat exchange system.In this paper,based on the multiple effect evaporator for water desalination device application background,use numerical simulation technology of horizontal tube falling film evaporation heat transfer and flow characteristics in the numerical simulation work,provide more comprehensive data support for the related research in the future.Through to affect the horizontal tube falling film spreading and evaporation performance of all kinds of factors of classified summarized,focusing on horizontal tube between the columnar flow pattern under the condition of outside tube falling film evaporation and spreading characteristics are simulated,and examines the columnar liquid column in the flow pattern of the knock-on effect on falling film spreading effect,discussed the influence of different factors on the liquid film thickness distribution;The spreading law and the distribution law of the thickness and velocity of the liquid film were compared and analyzed.Finally,on the basis of the falling film flow model,the heat transfer model was added to study and analyze the temperature distribution in the liquid film,and the influence of different factors on the heat transfer coefficient was analyzed.Results show that the column under the condition of flow pattern,flow fluid column to falling film have important influence on spreading and liquid film thickness distribution,and the kinetic energy of liquid column carries to promote the spreading of liquid film,which makes near the location of liquid column of liquid film thickness decreases,the flow velocity increases,due to factors such as physical property parameters,the Reynolds number of difference,between the horizontal tube can form along the rows and fork two columnar flow pattern.Flow pattern differences also reflect on the liquid film thickness distribution outside the tube,in-line flow pattern,the thickness of liquid film between adjacent fluid column into a v-shaped,drainage and fork type,between the adjacent liquid column follow on both sides of the middle thick thin liquid film thickness distribution characteristics,through the analysis of two kinds of flow pattern formation is the key to whether formed between adjacent fluid column obvious "wave" phenomenon,the emergence of the crest,drainage is suitable to fork type shift key.Inside the liquid film in the process of falling film spreading disturbance has had a huge impact on the inside of the liquid film temperature distribution,due to the effect of disturbance of the liquid film inside,between the adjacent liquid column and horizontal tube wake zone,the temperature distribution is more uniform.Finally,the heat transfer performance of falling film evaporation process analysis,through experiment and deserve a contrast test,the established heat transfer model can better simulate the heat transfer outside horizontal tube process of falling film Re inhibition effect to the falling film evaporation process,and the rise of evaporation temperature Tsat can enhance heat transfer performance of the system.