| Reservoir is a kind of multi-functional water conservancy project. For protecting people's lives and properties, and keeping the social stabilization, it is very important to study the transportation of the pollutant in the reservoir. Water body is the carrier of pollutant; therefore, it is significant to analyze the hydrodynamic characteristics of reservoir. Based on the previous studies, this thesis makes a systematic study on hydrodynamics characteristics and the transportation of pollutant in the reservoir. The research results are applied to early warning system of pollution accident of Zhipingpu Reservoir. The main contents and achievements of the study are as following:1. By virtue of simulating and analyzing a series of model reservoirs, the author puts forward a method, which divides the reservoir into three partitions according to the longitudinal velocity distribution, i.e. entrance area, well-developed flow area and outflow area.2. The influence of geometric factors, such as the contraction ratio of the entrance to the dam of reservoir, the ratio of width to depth of water body near the dam and the gradient of the reservoir bottom, on the range of different partition distributing are discussed here. Keeping other conditions unchanged, the range of the entrance area is enlarging along with the increasing of three geometry factors mentioned above. The range of the outflow area changes little while the contraction ratio of the entrance to the dam of reservoir and the ratio of width to depth of water body near the dam change. The gradient of reservoir bottom is not act on the rangeof the outflow area solely.3. This paper discussed the influence of operation flow rate and the vertical location of outlet on the reservoir hydrodynamics partitions. The effect of operation flow rate on the range of entrance area is greater than that of the vertical location of outlet. The longitudinal range of entrance area increases with the increasing of operation flow rate. When the outflow flux is small, the longitudinal range of outflow area increases with the increasing of flux, however, when the flux reaches to a certain degree, the range decreases with the increasing of it. If the the location of outlet is lower, the range of outflow area is larger when the gradient of reservoir bottom is rather small. If the gradient of reservoir bottom is high enough, the vertical location of outlet has no obvious influence on the range of the outflow area.4. After studying longitudinal velocity distribution in different hydrodynamic partitions, a new method to describe flow field is put forward. Assuming the depth is not changed and two flow fields of different flux are known, a new flow field of a new flux which is between the two known fluxes can be obtained by interpolating.5. A FORTRAN program to simulate the 3-D pollutant transportation in reservoir is developed. The reliability of model and the numerical methods are examined using analytical solution in the paper.6. According to the change of hydrodynamics characteristics, the pollutant transportation in different hydrodynamic partitions is studied in this paper. In entrance area, pollutant moves faster in longitudinal direction than in transverse and vertical directions because the longitudinal velocity is much greater than that in other directions. In well-developed flow area, pollutant transportation via convection is slower than that in entrance area for the longitudinal velocity becomes smaller here. Because velocities and turbulent viscosity become large in outflow area, contamination spread quickly in different directions.7. The impacts of operation flow rate and the vertical position of outlet on pollutant transportation in different Hydrodynamic areas are systematically studied in this paper. In entrance area, the effect of operation flow rate on distribution of pollutant zone in transverse direction slight but great in longitudinal direction. Asother conditions are unchanged, the moved distance of the foreside of pollution zone will be increasing with the increase of operation flow rate. For the case that the pollutant is discharged on the water surface, the effect of operation flow rate on longitudinal movement of the pollutant is greater than that the pollutant is discharged on the bottom of the reservoir. The trend of effect of operation flow rate on well-developed flow area is as the same as on the entrance area, but the effect is not obvious. In the outflow area, movements of pollutant in three directions are strengthened. Increasing of flow rate is favorable to moving of pollutant towards the outlet and the dam. Therefore the transverse spreading of pollutant zone will be restrained. The vertical location of outlet has no influence on the pollutant transportation in entrance area and well-developed flow area but has some influence on the pollutant transportation which distributing in outflow area.8. This paper makes a systematic study on the impacts of the operation flow rate and vertical position of outflow on the outflow of pollutant. For the three kinds of coming flow of pollutant, the increase of flow rate is helpful to the outflow of pollutant. During the same discharging time, the total quantity of the remained pollutant in the reservoir will be decreasing with the increasing of operation flow rate. When the high concentration pollutant flow is focusing on where above the outlet, the surface outflow discharging is the most beneficial to the outflow of pollutant, while the bottom outflow discharging is on the contrary. For the case of the high concentration pollutant flow is focusing on where below the outlet, or the pollutant is mixed well, the lower the outlet is, the more it is beneficial to the outflow discharging of pollutant.9. All results concluded above are applied to reservoir Zhipingpu. According to hydrodynamic characteristics and pollutant transportation in reservoir Zhipingpu, different emergency measures are put forward aimed at different purposes and different pollutant discharges. These offer an available basis for the managers. |
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