Flow Field Optimization And Heat Transfer Enhancement Of Air-Cooled Condenser Cell And System

Direct dry cooling system is widely used in power plants of North China thanks to its outstanding water conservation. The cooling air is driven by the large diameter axial flow fan to flow through the finned tube bundles of the air-cooled condenser cell non-uniformly, resulting in the poor utilization of the heat transfer surfaces and deteriorated cooling effect. The thermo-flow characteristics of the air-cooled condenser cell of the600MW generating unit were investigated by the CFD method. On the basis of the numerical results, the flow guiding measures were suggested in the air-cooled condenser cell to improve the flow and heat transfer performances. The actual model of the axial flow fan was adopted to obtain the exact aerodynamic characteristics at the exit of the fan. The porous media and radiator models were integrated to deal with the finned tube bundles in the present studies. The results show that the flow rate of the cooling air increases thus the heat transfer performance is improved due to the installation of the flow guiding device in the condenser cell. The performance improvement relies on the size and position of the flow guiding device. The flow field optimization in the condenser cell should follow the principle of local flow guiding and multi-zone layout.The thermo-flow performances of direct dry cooling system are remarkably influenced by ambient wind. The configuration of the wind turbine around the air-cooled condenser system was proposed to utilize parts of the wind energy, and lower the adverse effect of ambient wind on the air-cooled condenser system. It is a multi-discipline case, in which the blade design is the first key issue. The NACA4415airfoil is selected as the wind turbine blade for the present studies in the case of the Airfoil parameters limitation. The airfoils at various cross sections were obtained by an iterative calculation programming, and then the fan blade can be modeled by the software ProE. Three models with different distances between the wind turbine and air-cooled condenser system were setup. The thermo-flow performances of the air-cooled condenser were presented at four wind speeds. The results show that the superior space between the wind turbine and the air-cooled condenser system is about the length of the rotor diameter. At the present wind condition, low-power wind turbine reduces the air flow rate, but its rotary trail will result in a more conspicuous hot plume recirculation to air-cooled system. The improvement of thermo-flow performances for the direct dry cooling system by wind turbine configuration is not perfect in the present studies.