静止液体中射流和羽流污染混合区的理论分析

Analytical Solution to Pollutant Mixing Zone of Jets and Plumes in Static Liquid

以无限空间静止液体中自由紊动射流和密度差产生羽流的浓度分布理论解为基础,从水环境功能区管理的角度出发对不同条件下射流和羽流的污染混合区进行了理论探讨和求解.分别给出了平面和圆形射流以及羽流的污染混合区长度、最大宽度或直径、面积、体积的理论公式以及外边界等浓度标准曲线或曲面方程.结果表明,射流污染混合区长度与喷口起始浓度和水环境功能区所执行的标准浓度之比C0/Cs、喷口处断面几何尺度有关;羽流污染混合区长度与比值C0/Cs、起始流量和起始比浮力通量有关;平面和圆形射流、平面和圆形羽流的污染混合区宽长比依次为0.1317,0.1095,0.1564,0.1310,污染混合区为近似椭圆或近似椭球形状.可为生产实践中射流和羽流污染混合区的计算提供理论依据.

Based on the theoretical solution of the concentration distribution of simple turbulent jets and plumes produced by density deficiency in infinite space static liquid,the paper gives the theoretical study and solution of the pollutant mixing zone of jets and plumes in different conditions from the angle of the management of the water environmental function area.The theoretical formula of the length,maximum width or diameter,area,volume of the pollutant mixing zone of plane and round jets,plane and round plumes,as well as its outer boundary equal concentration standard curve or surface equation are given respectively.The result indicates that the length of the pollutant mixing zone of the jets is related with the geometry scale in the nozzle cross-section and C0/Cs which is the ratio of initial concentration of the nozzle and standard concentration implemented by the water environment function zones,and the length of the pollutant mixing zone of the plumes is related with the C0/Cs,initial discharge and initial buoyancy ratio flux.The ratio of width to length of the pollutant mixing zone of plane and round jets,plane and round plumes are 0.1317,0.1095,0.1564,0.1310 in order.The shape of the pollutant mixing zone is approximately elliptical or ellipsoidal,which can provide theoretical basis for the calculation of the pollutant mixing zone of jets and plumes in production practice.