盐淡水交汇水域电厂温排水及航道取水的试验研究

Model Studies on Heated Discharge into Estuary with Deepen Channel and on its Recirculation

笔者在珠海等火电厂排取水口物理模型试验中，把盐度作为一个独立变量进行模拟，研究了潮汐河口盐淡水交汇水域盐度梯度及其密度流对排取水口布置、冷热水掺混、热量输移和温升分布的影响。发现掺混后的热水不仅可浮在受纳水体上层，也可沉至受纳水体中层或下层，并获得了原体验证。珠海电厂取水口布置与港池相结合，充分利用了深水航道开挖后盐水入侵长度增加，盐淡水分层增强的水力特性。采用大流速浅排，增加盐淡水掺混，减下热水下沉，减小近区热水回归ΔＴｎｄ；借助上层淡水径流和密度流，有利于热量向湾外输移，减小远区热量累积ΔＴｆｃ；利用深水航道下层密度流，取得湾外深层高盐低温水ＴＮ，使取水温度Ｔ２最低。即：Ｔ２＝ＴＮ＋ΔＴｎｄ＋ΔＴｆｃ。

The salinity with tidal currents and temperature rise from the heated discharge of thermal power plant have been simulated by a distorted scale physical model for studing the interaction of them.It is found out both in the model and prototype that the heated effluent mixed with ambient water may be concentrated in the upper ,middle or lower layer of the main receiving water body or unit formally distributed along water depth of it due to the change of the vertical salinity gradient. The heated effluent can be prevented from sinking and kept in the upper layer by adoptting higher discharge velocity through a layout consisting of water surface outfall and of submergent intake connected to deepen channel so that not only the decrease of heat impact on environment but also the cooling water of little heat direct recirculation and accumulation and of lower natural water temperature can be achieved by means of the density current..