浅海中海水淡化高盐度尾液排放的试验研究

近年来由于淡水资源短缺和海水淡化处理成本的显著下降，海水淡化产业在全球范围内蓬勃发展。出于环境保护考虑，保证海水淡化后产生的高盐度尾液能够迅速与受纳海水掺混的排放口设计显得尤为重要。目前实践中广泛采用的型式是圆形倾斜淹没式排放，而之前的研究建议倾角设计与水平方向成60°为最佳。但伴随60°倾角的射流上升高度相对较高，可能不适用于排放入浅海海域。应用先进的粒子图像测速（PIV）和平面激光诱导荧光（PLIF）技术在实验室模拟较小角度（30°和45°）的排放，从而研究其掺混及稀释特性。通过实验数据整理得到相应的射流最大上升高度、碰撞点水平距离、碰撞点稀释度等属性，从而为浅海区的海水淡化高盐度尾液排放的工程设计以及相关规定的制定提供参考。

EXPERIMENTAL INVESTIGATION ON DESALINATION DISCHARGES IN SHALLOW COASTAL WATERS

The desalination industry is undergoing a fast development in the world due to water shortage and significant reduction in production cost in recent years. For environmental concerns, a proper design of the brine outfall is essential to enable the end discharge mix rapidly with the ambient coastal waters. A widely adopted practice is an inclined round submerged discharge at the seabed, with an inclination angle of 60° to the horizontal to optimize the mixing efficiency. However, the maximum rise height associated with 60° is relatively large and thus unsuitable for disposal in shallow coastal wasters. In this study, the authors investigated the mixing efficiency of a submerged round brine discharge at smaller angles (30° and 45°) by using advanced laser diagnostic approach of combined Particle Image Velocimetry (PIV) and Planar Laser Induced Fluorescence (PLIF). Based on the experimental results, characteristic geometrical features were identified in dense discharge flow, such as terminal rise height and horizontal location and dispersion degree of the impact point, where the downward flow impinges the base. The results may be of regulatory reference for the mixing pattern of the brine plume in surrounding coastal waters.