| The flow of air in the tower is directly affected by the air cooling tower structure.The aerodynamic characteristic in the air cooling tower will have an important influence on the cooling effect of the air cooling system.Therefore,it is of great significance to study the flow and heat transfer characteristics of air flow in the air cooling tower and improve the structure of air cooling tower.In this paper,the flow field and temperature field of natural ventilation air cooling tower was studied from experimental and theoretical perspectives.In the research process,the flow field experimental platform of air cooling tower have been designed,constructed and debugged,and the tower type optimization and the cause of change of flow field was discussed.In order to study the change of flow field and temperature field in natural ventilation air cooling tower with working conditions,a simplified mathematical model of air cooling tower was presented,and the boundary conditions of air cooling tower inlet and outlet were analyzed and calculated.Besides,According to the similarity theory,the dimensionless number equation of air cooling was derived,and the Gr dimensionless number was choosen as the similarity criterion of the flow field experiment model of the air cooling tower,and on the basis of the principle of the mould area,the rate of the model of the tower was dertermined.To design and make the temperature control system tower,the material selection,design,installation of model tower and the simplified methods of radiator were studied.By improving the test scheme and selecting the experimental apparatus,the PIV experiment was carried out on the model tower,and the flow field,temperature and velocity of the model tower under different inlet temperature conditions were discovered.The test results show that the reason why the flow field in the air cooling tower changes with the working condition is that the effect of inertia force,temperature difference inside and outside the tower,temperature difference between the side wall and the center of the tower increases gradually with the increase of inlet temperature and the latter increases faster than the former.When the two of them restrict each other,the closer the flow state is to the ideal flow state.When remodeling the cooling tower,it is a good idea to use vertical wall to replace curved wall,which is conducive to steel member processing,and use Straight pipe outlet or tapering outlet to replace tapering outlet,which is beneficial to avoid the return of the outlet airflow.And it is more better to choose 42?-47? as the operation condition,in which temperature the result of the hyperbolic cooling tower is with the most consistent operating conditions,and it is in the transition zone,which is conducive to the analysis and comparison of experimental results and theoretical results. |
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