辅助通风湿式冷却塔热力性能的变工况研究

Study on Thermal Performance of Auxiliary Ventilation Wet Cooling Tower under Variable Operation Conditions

为探究变运行工况对辅助通风湿式冷却塔热力性能的影响,建立了淋水面积为7 500 m2的辅助通风湿式冷却塔热力性能三维数值计算模型,分析了辅助通风对塔内空气流场及温湿度场的作用规律,计算了不同循环水流量、淋水密度和环境湿球温度下冷却塔的通风量及循环水温降,并与常规冷却塔进行了对比。研究表明:进风口辅助通风主要提高了风机迎面区域和冷却塔中心区域的通风量,且其对中心区域气水换热的强化作用最明显;辅助通风对整塔通风量的提升量基本保持在1 160~1 200 kg/s之间,随运行工况的变化程度较小;随着循环水量的增加,辅助通风对循环水温降的增效作用越来越明显,温降最大升高了0.4℃,而进塔水温和环境湿球温度基本不影响辅助通风对循环水温降的增效作用。

In order to study the influence of variable operating condition on the thermal performance of auxiliary ventilation wet cooling towers,a three-dimensional numerical calculation model for the thermal performance of a cooling tower with a water drenching area of 7500 m?was established,and the ffect of auxiliary ventilation on the air flow field and temperature and moisture fields in tower was analyzed.The ventilation quantity and the circulating water temperature drop of cooling tower under dfferent circulating water flow rates,water drenching densities and ambient wet bulb temperatures were calculated,which was compared with that of conventional cooling tower.The results show that the auxiliary ventilation at the air inlet mainly increases the ventilation quantity at the facing area of the fans and the central area of the cooling tower,and its enhancement effect on the air-water heat transfer at the central area is the most ob-vious;the increase of auxiliary ventilation on the ventilation quantity in tower is basically maintained be-tween 1160 kg/s and 1200 kg/s,which is less affected by the operating conditions;with the increase in the circulating water flow rate,the effect of auxiliary ventilation on circulating water temperature drop becomes more and more obvious,with a maximum increase value of 0.4℃.In addition,the water temperature and ambient wet bulb temperature have no prominent effect on the efficiency of the auxiliary ventilation on circulating water temperature drop.