通过水槽实验和理论分析, 研究了水动力条件对水体自净作用的影响, 发现水流流速是影响水体自净作用的 主要因素之一, 不同断面及水深条件下水体自净作用的差别不是特别明显。分别采用生化需氧量2溶解氧耦合模 型和化学一级反应拟合并预测了水质随时间的变化关系。水流流速的增加在一定程度上提高了水体复氧能力, 增强了水体的自净作用。当流速超过一个临界值使得底泥再悬浮发生时, 水体自净作用在短时间内急剧降低。 在引水工程中, 合理控制和设计水力参数( 流速流量、取水周期及间隔、增加消能水工建筑物) 是控制水体水质的有 效措施。

The effect of hydro dy namic conditio ns o n the self2purificat ion of w ater body w as studied thro ug h the w ater flume ex2 periments and theor etical analysis. It was found that flow velocity was o ne o f the main facto rs affecting the self2purificat ion of water bo dy , w hile differ ent sectio n and w ater depth co ndit ions did not make much difference on the self2purificat ion o f w ater bo dy . We adopted t he bio chemical ox yg en demand2disso lv ed ox yg en co upling mo del and chemical f irst2o rder r eaction to pr edict the v ariat ion of w ater quality with time. T o some extent, the increase o f w ater f low v elocity improv ed the reaerat ion ability of water bo dy and enhanced the self2purificatio n effect of w at er body . H ow ever, when the f low velo city ex ceeded a certa in value causing sediment resuspension, the self2purification effect o f the w ater body decreased shar ply in a sho rt time. In a w ater diver2 sio n pr oject, reasonable contro l and design of hy dr aulic parameters such as flow velo city and discharg e, w ater intake perio d and interval, and incr ease o f ener gy dissipation hy dr aulic str uctures are effectiv e measures to co ntr ol water quality.

国家重点研发计划( 2016YFC0401504) ; 国家自然科学基金( 11032007; 11502138) ; 中国博士后科学基金( 2015M581580)