钢塔对间冷散热器换热性能的影响

Influence of steel tower on the heat transfer characteristics of indirect air cooled radiator

利用计算传热学软件Fluent,在自然通风状态下,对国内首个2×660 MW机组钢结构外覆铝板冷却塔间接空冷散热器的流动和换热性能进行数值模拟、分析和研究.考核工况下,水平加强环对散热器换热量和钢塔通风量的影响约占设计值的2.7%;铝板换热量约占机组排热量的0.6%;随着环境风速的增大,钢塔抽力逐渐降低;当环境风速高于10m/s时,出现塔内热空气流出冷却柱的现象;当环境风速高于20m/s时,塔内出现"穿堂风",间冷散热器的换热量和钢塔通风量明显增加;当环境风速低于12m/s时,随着环境风速的增大,间冷散热器的换热量和钢塔通风量逐渐降低;当环境风速高于12m/s时,随着环境风速增加,间冷换热量和钢塔通风量呈增大趋势.

By using the numerical heat transfer software FLUENT,the flow and thermal characteristics of the first 2×660 MW units indirect air cooled radiator（IACR）in China is numerically simulated,analyzed and studied under natural draft,whose steel-structured air cooling tower is coated with aluminum sheet.Under the performance assessment working condition set in this paper,the difference value of the heat transfer amount of IACR and ventilation volume of steel tower between units with and without horizontal stiffening rings takes up about 2.7% of the designed heat transfer amount.The heat transfer amount of aluminum plates takes up about 0.6% of the power units′heat rejection amount.The driving force of steel tower decreases as wind speed increases.Hot air in steel tower flow out through cooling column as wind speed is greater than10m/s.Wind gust through the tower appears as wind speed is greater than 20m/s,and the heat transfer amount of IACR and ventilation volume of steel tower apparently increase.When envi-ronmental wind speed is less than 12m/s,heat transfer amount of IACR and air flow rate of steel tower gradually decrease as wind speed increases.When environmental wind speed is greater than12m/s,heat transfer amount of IACR and air flow rate of steel tower tend to increase as wind speed decreases.When environmental wind speed is greater than 12m/s,heat exchange rate of IACR and air flow rate of steel tower show the tendency of increase as wind speed decreases.