Numerical Simulation And Analysis On Internal Flow Field Of Air-cooled Unit With Deflectors

Due to its obvious effect of water saving, direct air cooling unit has been widelyusing in the power plants of some districts in China, in which there are full of coal butlack of water resources. However, many problems related to air cooling unit still existand need to be solved, such as, the local high temperature at the bottom four corners ofthe radiator is one of the problems. All of like these problems have been directlyaffecting the safety and economic operation of the air cooling units. So, it is of veryimportant practical significance to research the topic.For the typical structure of direct air-cooled condenser cell of the600MWgenerating unit, the deflectors are installed in the air cooling cell in the paper in order todecrease the local high temperature at the bottom four corners of the radiator, and hence,to improve the flow and heat transfer characteristics. Accordingly, the numericalsimulation and analysis are conducted for internal flow field and temperature field in theair-cooled cell before and after the installation of deflectors mainly using FLUENTsoftware in this paper. Firstly, the effects of different deflectors on heat transfer of aircooling cell are simulated, calculated, and analyzed, and the appropriate number andshape of deflector are acquired. Secondly, the installation angle, size and arrangement ofthe deflectors are also simulated and analyzed. The results indicate that installing certaindeflectors in the condenser cell can improve the heat dissipation effect of air cooling cell,and the degree of improvement in heat transfer is different with different number, shape,size and arrangement of deflectors. Arrangement of reasonable optimal number and sizeof deflectors in air cooling cell can improve the internal flow field and temperaturedistribution, increase the uniformity of cooling air flow field, and greatly reduce the localhigh temperature of the heat exchanger tube bundle as well as average temperature in theexport of finned tube air side, which can effectively reduce the exhaust steam pressure ofsteam turbine, and raise the safety and economic operation level of air cooling unit.