直接空冷机组空冷单元内喷雾增湿系统的结构优化

Numerical Research of Spray Humidification System under Circular Arrangement in the Direct Air-unit

基于SIMPLE算法,采用k-ε模型,在综合两相流、传热传质理论并结合实际运行效果的基础上,对600 MW直接空冷机组空冷岛中的1个单元进行数值模拟,分析喷嘴纵向双层四排布置时喷嘴位置、喷雾方向、喷嘴孔径及喷雾压力对空冷凝汽器压力的影响。结果表明:喷嘴双层四排布置时,压力越大喷雾增湿效果越明显;综合考虑雾化效果和喷雾距离,1 mm为孔径的最佳值;当外排喷嘴距风机栈道中心线4 m、距风机平面高度为0.6 m、内排喷嘴距风机栈道中心线2 m、距风机平面高度1.9 m、喷雾方向在xy平面内与y轴正方向夹角为120°、喷雾压力为1.2 MPa、孔径为1 mm时,空冷凝汽器压力降幅最大,可降低8.13 kPa。

With SIMPLE algorithm and k - εmodel, applying the heat and mass transfer theory for two-phase of air and water, 3D mathematical model of spray humidification system for 600 MW direct air-cooling unit has been established and an analysis carried out to the influence of nozzle height, nozzle orientation, spray pressure and nozzle diameter on the spray humidification effect, in double longitudinal nozzle arrangement. Results show that ： the greater the pressure, the more obvious effect of spray humidifier is. Taking the atomization effect and spray distance into comprehensive consideration, the most proper aperture is 1 ram. Maximum pressure drop （8. 13 kPa） is to be obtained under outer nozzles are symmetrically arranged 4 m away to trestle center of air fan, nozzle height is 0. 6 m ; inner nozzles are symmetrically arranged 2 m away to trestle center of air fan, nozzle height is 1.9 m ; the angle between nozzle direction and positive direction ofy axis is 120°. in the xy plane, the nozzle size is 1 ram, spray pressure is 1.2 MPa.