Experimental Investigation On Condensation In Shell And Tube Heat Exchanger

The flow process of condensation in the tube is a complex process and it includes two phase flow and phase change heat transfer. With the understanding of mechanism on condensation heat transfer, a lot of research on the characteristics of condensation heat transfer has appeared. There are two main methods to study the characteristics of condensation heat transfer. The first one is to establish the mathematical model with simulation software. The pressure, temperature, speed, density, and so on can be obtained by calculating and the results can be analyzed. The second one is to get data by experiment and then make an analysis of the experiment results.The paper studies the characteristics of the condensation of flow and heat transfer about in twist tube and smooth tube through experiment. The experiment works with steam-air fluid. The main work and conclusions of the paper are as follows:(1) The paper studies the characteristics of the condensation of flow in twist tube and light tube. Some conclusions are obtained through experiment data. The friction coefficient decreases with the increase of Reynolds number. The friction coefficient of the twist tube is higher than smooth tube. The pressure drop decreases with the increase of the quality gas rate. The pressure drop increases with the increase of heat flux. The pressure drop of the twist tube is higher than smooth tube.(2) The paper studies the characteristics of the condensation of flow in twist tube and smooth tube. Some conclusions are obtained through experiment data. The Nusselt number increases with the increase of Reynolds number. The Nusselt number of the twist tube is higher than smooth tube. The heat transfer coefficient decreases with the increase of the quality gas rate. The heat transfer coefficient of the twist tube is higher than smooth tube.(3) Under the two-phase flow conditions, the paper gives the relationship between comprehensive evaluation factor of enhanced boiling heat transfer and Reynolds number of flat spiral pipes with different pitch. The paper makes a comprehensive analysis of the characteristic of condensation heat transfer in the twist tube.(4)The paper makes nonlinear regression with experiment data. On the basis of the existing empirical model, the relationship of Friction coefficient, Nusselt number and Reynolds number is obtained.(5) Compared to the smooth tube, the twist tube can strengthen the condensation heat transfer in the cube. But it also increases the flow resistance. The effect is not obvious by changing the pitch to improve the heat transfer performance of twist tube.