Design And Verification Of Flow Resistance Test Bench For Transverse Tube Falling Film Bundle

In the context of the increasing shortage of energy and water resources,energy saving and emission reduction has become an important national policy in China,Evaporative condensers have been widely used in engineering fields such as electric power and seawater desalination because of their advantages such as energy saving and water saving.Therefore,the in-depth study of the evaporative condenser is of great significance to the practical application of the project.At present,there are many researches on the heat transfer performance of evaporative condensers at home and abroad,and the research on the flow resistance of air is less.This article from the perspective of engineering practice,the flow resistance and heat transfer test bench of the horizontal tube falling film evaporating condenser tube bundle are designed to be able to complete study the resistance of air flowing through the transverse tube bundle under different tube bundle shapes,tube spacing,cooling medium,spray density,oncoming wind speed,and heating power.After completing the construction of the test bench,a preliminary cold test was carried out using a brass tube(H62)with a diameter of 38 mm as the heat exchange tube bundle.It is verified that the test bench has the function of meeting the performance test of the evaporative condenser,the experimental results were as follows:Within a certain range,the air flow resistance increases with the increase of the spray density and the oncoming wind speed.When the oncoming wind speed reaches about 2.5 m/s,the air flow resistance increases at the fastest;and in the spray state,The air flow resistance is unevenly distributed along the pipe row direction.As the number of pipe rows increases,the air flow resistance increases stepwise.At the same time,it is also found that the relative humidity change of the inlet and outlet of the evaporative condenser decreases with the increase of the spray density.However,it is almost unaffected by the oncoming wind speed;Comparing the experimental data in both the air countercurrent and the downstream,it is found that at the same spray density,the flow resistance in the countercurrent flow is about 1.4 times of the flow resistance in the forward flow.