Analysis Influence Of Arrangement And Windbreak Wall Setting About Radiator Of Indirect Dry Cooling System On Heat Transfer Performance

In today's society,there is a shortage of water resources.Therefore,water conservation and water utilization improvement have become major development strategies for sustainable development in our country.The construction of traditional wet and cold aircrews needs to consume a large amount of water resources.Air-cooled units with air cooling technology have significant water-saving effect.Therefore,the indirect dry cooling towersare widely used in water-scarce places.In this paper,the influence of different arranged schemes of radiator of 660MW SCAL on its heat transfer performance was studied.Based on the study of the traditional arrangement scheme,the circular arranged scheme,the elliptical arranged scheme and the horizontal circumferential arranged scheme in the tower were proposed.Firstly,the geometric models of different arranged schemes were established considering whether the buildings around the tower is exist.The different grid division and particular boundary conditions were set.The grid independence verification was carried out,and was compared with the verification conditions,and the result showed that the model met the actual engineering needs.Then the mathematical model was established by using the energy equation,the momentum equation,the continuity equation and the k-?equation.Both simple effectiveness model and porous medium model were adopted for the radiator of the indirect dry cooling system.The velocity field and temperature field distribution of the indirect dry cooling system under different ambient wind speeds and different arranged schemes were obtained by CFD simulation,and the heat transfer performance was analyzed and compared.Finally,according to the field distribution of the traditional arrangement scheme,three improvement schemes were proposed,namely,the windbreak wall was arranged outside the tower?A₁ scheme?,the windbreak wall was arranged inside the tower?A₂ scheme?,and the windbreak wall was arranged at the same time inside and outside the tower?A₃ scheme?.The simulation results show the following:When there is no ambient wind,the existence of buildings around the tower has almost no effect on the heat transfer performance for the different layout schemes of the radiator.For the layout of the traditional arrangement scheme and the presence or absence of buildings around the tower,the total mass flow rate and total heat rejection of the tower tend to decrease and then increase with the increaseing of the ambient wind speed,and the minimum is obtained at 12m/s.Due to the existence of buildings around the tower,the maximum and minimum values of the change in mass flow rate are obtained at 18m/s and 12m/s respectively,and the maximum and minimum values of the change in heat rejection are obtained at 5.5m/s and 18m/s respectively.For the circular arranged scheme and the presence or absence of buildings around the tower,as the ambient wind speed increases,the total mass flow rate of the tower decreases and then increases,and the minimum value is obtained at 12 m/s.When there are no buildings around tower,the total heat rejection of the tower decreases and then increases with the increasing of the ambient wind speed.The minimum value is obtained at 12m/s.When there are buildings around the tower,the total heat rejection of the tower has a trend which is first reduced,then increased and decreased,and finally increased with the increasing ambient wind speed,and the minimum value is obtained at 15m/s.Due to the existence of buildings around the tower,the maximum and minimum values of the change in mass flow rate are obtained at 15m/s and 5.5m/s respectively,and the maximum and minimum values of heat rejection are obtained at 12m/s and 18m/s respectively.For the arrangement of the wind direction perpendicular to the elliptical ring of the major-axis,the total mass flow rate of the tower decreases and then increases with the increasing ambient wind speed under no buildings around the tower,and the minimum value is obtained at 8m/s.When there are no buildings around the tower,the total heat rejection of the tower firstly decreases,then increases and decreases,and increases at last with the increasing of the ambient wind speed,and the minimum value is obtained at8m/s.When there are buildings around the tower,the total heat rejection of the tower decreases firstly and then increases with the increasing of the ambient wind speed,and the minimum value is obtained at 12m/s.Due to the existence of the buildings around the tower,the maximum and minimum values of the change in mass flow rate is obtained at8m/s and 12m/s respectively,and the maximum and minimum values of change in heat rejection are obtained at 15m/s and 12m/s respectively.For the wind direction parallel to the elliptical ring of the major-axis,the total mass flow rate and total heat rejection of tower decrease and then increase with the increasing of ambient wind speed,and the minimum value is obtained at 12m/s.For the horizontal circumferential arrangement of the tower,the overall heat transfer performance of the downstream is better than the overall heat transfer performance of the upstream.The total mass flow rate and total heat rejection of the tower are reduced with the increasing of the ambient wind speed.For the horizontal circumferential arrangement of the tower,the overall heat transfer performance of the downstream radiator is better than the overall heat transfer performance of the upstream radiator.The total mass flow rate and total heat rejection of the tower are reduced with the increasing of the ambient wind speed.Compared with the traditional arrangement scheme,for the horizontal circumferential arrangement of the tower and the arrangement of the wind direction parallel to the major-axis elliptical ring,the heat transfer performance is generally inferior to the traditional arrangement scheme;for the wind direction perpendicular to the major-axis elliptical ring arrangement,the heat transfer performance is better than the traditional arrangement scheme;for the traditional arrangement scheme,when the ambient wind speed changes within a certain range,its heat transfer performance is better than that of the traditional arrangement scheme.The heat transfer performance of the A₁,A₂ and A₃ improvement schemes is improved compared with the traditional arrangement scheme.The heat transfer performance of the A₁ scheme and the A₃ scheme is also improved compared with the A₃scheme,and the heat transfer performance of the A₃ scheme is improved more than that of the A₂ scheme.So A₃ scheme is the best solution and the A₂ scheme is the worst solution.In a summary:the research on the arranged scheme of the radiator provides a new idea for improving the heat transfer performance of the indirect dry cooling system,which is very significant;at the same time,the windbreak wall can also improve the heat transfer performance of the indirect dry cooling system.For areas with a fixed wind direction,the A₃ scheme of this paper can effectively improve the heat transfer performance of the indirect dry cooling system.