Numerical Simulation Of Cooling Water In Jaozhou Bay

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.