Performance Analysis Of A Directed Air Cooled Steam Condenser With The Guide Vanes

The direct air-cooled technology has been developed in recent years,and is becoming more and more mature,it's in the stage of wide application.The DACC uses ambient air as the medium to cool the steam turbine exhaust.Air cooled condenser is the core equipment of direct air cooling system,so its reliable cooling performance is the key to the stable and economic operation of power plant.The DACC's heat transfer performance seriously affected by environmental wind.In this paper,Reference to a domestic power plant's 600 MW Direct Air-Cooled Unit,Based on the operating characteristics of direct air-cooled unit,we propose a guide vanes used in the air-cooled platform,and eight different types of diffuser guide vanes are designed.Base on Fluent,calculating the heat transfer performance of air-cooled condenser that installed diffuser guide vanes.The improvement of heat transfer performance of direct air cooled condenser was analyzed by the installation of diffuser guide vanes.At the same time,the influence of blade guide angle,blade number and the blade cascade installation position on the heat transfer performance of direct air cooled condenser was studied.The results show that,the installation of the diffuser guide flow vanes can effectively improve flow field of air cooling unit under the condition of ambient wind,eliminate the vortex at the entrance of the air cooling unit and the fan,and reduce the average temperature of the cooling air at the entrance of the axial flow fan.Among them,the more the air cooling units near the upwind surface,the more obvious the effect is.Secondly,the installation of the diffuser guide flow vanes can improve the heat transfer performance of the air cooled condenser.When the ambient wind speed is higher,the optimization effect is obvious.Under the ambient wind speed of 8m/s,the whole heat transfer efficiency of the air cooling unit,after adding the diffuser guide flow blade cascade,is increased by 8%.The comparison results show that,among the eight types of blades,the performance improvement of air cooled condenser is the most significant in blade cascade composed of NACA6412 blades.On the basis of this,the structure parameters of the diffuser guide flow blade cascade are optimized,and the optimal bladeguide angle is 45 degrees;and the more the number of blades,the more obvious effect.The overall heat transfer performance of the condenser can be further improved by adding a row of blade cascade in the middle of the air cooling unit.