Influence Of Ambient Temperature Vertical Distribution On Thermos-flow Characteristics Of Air-cooled Steam Condenser

Because of obvious water conversation and environmental protection,direct dry cooling system is widely used in coal-rich and water-deficient areas.The Since ambient air is used as the cooling medium in an air-cooled steam condenser the achievable heat transfer rate is susceptible to influence from the ambient conditions such as wind,temperature and atmospheric instabilities.Significant diurnal temperature variations exist near the ground in the atmospheric boundary layer due to radiative heating and cooling of the earth’s surface.so it is of great significance to investigate the influence of environmental temperature distribution on the performance of the air cooling condenser.By the base of the typical 2×600MW direct air-cooled plant in the paper,four typical periods of one day is selected,the flow and temperature fields of cooling air for the vertically arranged air-cooled condensers at ambient winds are obtained by means of the CFD simulation and experimental validation,and then the influence of atmospheric temperature distribution on the thermal-flow performance of air cooling unit is analyzed by comparing with two cases which set the reference temperature as environmental temperature.The two cases are respectively setting the reference temperature as the air temperature of platform height and the mass-weighted average temperature.The results show that the inlet air temperature distribution of air-cooled condensers is different with other two cases which set the reference temperature as environmental temperature,and the inlet air temperature of downstream fans is higher when considering the atmospheric temperature changes with altitude.It shows that fans which are not at the edge of the air-cooled condenser are easier affected by fans which of performance is deteriorative.Considering the atmospheric temperature distribution,the wind cluster effect is more apparent.The effect of the atmospheric temperature distribution on the thermalflow performance of air-cooled condenser is different at various wind speeds and in various wind directions,heat transfer performance of air-cooled condenser is affected by both wind field and temperature field.