鲅鱼圈热电厂温排水的现场观测和三维数值模拟

In-situ observation and three-dimensional numerical simulation of cooling water discharge from Bayuquan thermal power plant

为研究鲅鱼圈热电厂温排水的热污染问题,对其附近海域潮流和水温进行了现场观测,并利用RMA-10三维有限元模型模拟热电厂附近海域海水温升场的分布。现场观测和数值模拟结果表明：（1）温排水对电厂邻近海域温度分布影响明显,模拟得出鲅鱼圈海域表层海水受电厂温排水影响温升在1℃和4℃上的面积平均值分别为0.648 km2和0.199 km2;（2）热羽面积变化趋势与涨、落潮过程呈现高度相关性,同一潮次中低潮时刻热羽面积大于高潮时刻。（3）海水温升分布呈现出较明显的垂向差异,表层温升面积为底层温升面积的2～4倍,表明由于温差所产生的浮力效应,温排水主要集中于海水表层流动。研究结果表明通常采用的基于垂向平均的二维温排水数值模型无法精确模拟温度分层,只有建立三维模型才能对温排水引起的温升场进行精确模拟。

To study the thermal pollution caused by cooling water discharge from Bayuquan thermal power plant,in-situ measurements of the tidal currents and the heat diffusion in the surrounding area of the power plant were conducted in this study. Three-dimensional finite element numerical model RMA-10 was also used to simulate the three-dimensional temperature rise field caused by cooling water discharge from the power plant. The major findings are as follows：（ 1）The temperature distribution is significantly affected by the cooling water discharge. The model predicted average area with over 1℃ and 4℃ temperature rise in the surface is 0. 648 km2 and 0. 199 km2,respectively;（ 2） The extent of cooling water discharge appears to correlate directly with the tidal currents. Over a tidal cycle,the extent of the thermal plume during the low tide is larger than that during the high tide;（ 3） The vertical distribution of temperature rise is not uniform,and the area with temperature rise in the surface is 2 to 4 times larger than in the bottom,suggesting that cooling water diffuses mainly in the upper layer due to the buoyancy effect. As such,the commonly used two-dimensional model may not be suitable for simulating cooling water discharge,and three-dimensional model is preferable in such a case.