【作者】 常小军；

【导师】 鲍献文；

【作者基本信息】 中国海洋大学 ， 物理海洋学， 2011， 硕士

【摘要】 温排水是指用作电厂凝结器的冷却水,温升约7-10℃后重新排回水体的那部分水。近年来随着沿海核电站、火电站的兴建,大量温排水排入近岸海域,使得海洋热污染问题逐渐突出。水体温度升高会引起水中溶解氧含量降低,影响鱼类和其他水生生物的生存和繁殖,还会带来水体富营养化、水质恶化等环境问题。温排水排入海洋后,在热扩散效应和海水输运的作用下,使影响海域海水的温度场结构发生改变。尽可能准确地预测温排水影响下海水温度的分布,为评估温排水对环境影响、解决海洋热污染问题提供了必要科学依据。本文针对胶州湾内地形复杂、岸线曲折并有大面积滩涂存在的特性,建立三维FVCOM水动力模型对其潮流场进行了数值模拟,水位和潮流的模型结果与实测数据吻合较好。模型结果表明:温排水影响的电厂附近海域属于正规半日潮,潮流以往复流为主,涨潮方向为NE,落潮流方向为SW,最大潮流流速可达60cm·s-1。在水动力模型的基础上,开发了一个温排水的三维对流扩散模型,并以胶州湾内的青岛电厂的温排水为例,利用此模型对温排水引起的该海域的三维温升场进行了模拟。模型结果表明:海水表层的温升较大,海泊河河口附近海域温升可达4℃以上,表层向下温升迅速减小,尤其是表层到中层,变化尤为剧烈,底层的温升值很小,除海泊河内区域外,其他海域温升很小,温升基本在0.2℃以下。说明由于温差所产生的浮力效应,温排水主要集中在海水的中上层运动扩散,海水温升分布呈现出明显的垂向差异,普遍采用的基于垂向平均的二维温排水数值模型无法模拟这种情况,只有建立三维模型才能对温排水引起的温升场进行更加准确地模拟。同时,本文采用不同的海面综合散热系数,分别取为0、50和100,研究了海面综合散热系数的取值对温升分布的影响。模拟结果表明:随着K s取值的增大,各条温升线的包围面积有较为明显的减小,而且温升值越小,温升线的包围面积减小越显著,说明了K s的取值对温升场分布的重要性。对温升场进行预测时,只有根据所研究海域的实际水文气象条件确定合理的海面综合散热系数,才能得到较为准确的温升场分布情况。前人对温排水的研究基本都集中在海水温升场的分布上,而水生生物生存的敏感因子是海水温度。所以,要更加准确地探讨温排水对受纳水体生态环境及水生生物的影响,就要对温排水影响下的海水温度场进行模拟。本文综合考虑海气界面的太阳辐射、海面有效回辐射、潜热通量和感热通量,在模型中嵌入块体公式计算感热和潜热通量,对在温排水影响下胶州湾的温度场进行了数值模拟。计算结果表明:在合理地考虑了海气热通量后,温度场的计算结果和实测结果较为一致。更多还原

【Abstract】 Cooling water means the water used to cool the condenser in power plants that returns to the sea with a temperature rise of about 7-10℃. With the massive building of nuclear power plants and thermal power plants in the coastal area, plenty of cooling water discharges into the sea .The heat pollution issue becomes more and more notable.The rise of temperature in the water body could cause the decline of dissolved oxygen affecting the living and breeding of the fish and other acquatic organisms and bring on the environmental problems of eutrophication and water quality deterioration et.With the effect of heat diffusion and tranport of sea water, cooling water can change the structure of temperature field. The accurate calculation of the distribution of the water temperature filed provides the necessary scientific basis to evaluate the influence of cooling water on water environment and slove the heat pollution.According to the features of Jiaozhou Bay, such as the complex terrain, flexural coastline and the large area of tidal flat, 3-D hydrodynamic numerical model FVCOM is used to simulate the tide of this area. The model results of elevation and current aggree well with the observed data.The model results show that in the sea area affectd by cooling water the type of tide is regular semidiurnal tide and the tidal current is mainly on reciprocating flow with the maximum velocity of 60cm·s-1.The direction of flood current is NE,while the direction of ebb current is SW.Based on the hydrodynamic model, a high resolution numerical model of 3-D cooling water is adopted to calculate the three-dimensional temperature rise field caused by cooling water from Qingdao power plant in Jiaozhou Bay.The model results show that the value of temperature rise in the surface is relatively large,which is over 4℃in the area around the mouth of Haibo river. The value of temperature rise decreases rapidly downward the surface,especially from surface to middle layer.In the bottom the value of temperature rise is very small.Besides the area in the Haibo river the value is below 0.2℃in most area.The results show that cooling water diffuses mainly in mid-upper layer.There is a dramatic difference in the veritcal distribution of temperature rise which 2-D cooling water model couldn’t simulate.Only 3-D model can simmulate the temperature rise field more accurate.Meanwhile,this article adopts different values (0,50,100) of the synthetic heat dissipation coefficient in the water surface to study its influence to the distribution of temperature rise.The model resuts show that with the increase of the synthetic heat dissipation coefficient the area enclosed by temperature rise line declines apparently. The smaller the value of temperature rise is ,the more the area enclosed by the temperature rise line decreases.It indicates that the synthetic heat dissipation coefficient affects the distribution of temperature rise greatly.In the practical prediction of cooling water,the rationality of value-taking of the coefficent is essential.In the form studies of cooling water, the focus was mostly on the distribution of water temperature rise. But the sensitive factor of living of acquatic organisms is the water temperature.To study the impact of cooling water on ecological environment and acquatic organisms , simulating the temperature field affected by cooling water is necessary.This paper takes solar radiation, effective counter-radiation, latent heat flux and sensible heat flux in the sea surface into account. Incorporated with the bulk formula to calculate the sensible and latent fluxes, the model is used to simulate the temperature filed with the influnce of cooling water in Jiaozhou Bay.The result shows that with regrad of heat flux in the sea surface, the model result agrees well with the measured data.更多还原