The Study On Transport Characteristics And Control For Oil Pollution In Water Transfer Project

In general, the water transfer project contains kinds of hydraulic structures, such as open channels, check sluices, inverted siphons, etc. Obtaining oil pollution transp-ort characteristics and clearing the pollution scope of oil slick are the foundation of oil emergency disposal quickly and efficiently for sudden oil pollution accidents in water transfer project. Obtaining the conditions of oil submergence in front of check sluice and inversed siphon import are of great significance to ensure the water supply and water quality security. The main works of this paper are as follow.(1) A two-dimensional hydrodynamic and oil spilled numerical simulation model of open channels was established to simulate the migration characteristics in normal water transport condition. The longitudinal length of oil slick rate is 0.5 times middle velocity of channel, which is verified by physical model test and not affected by the oil-spilled location, wind and the slope coefficient. Closing sluice gates immediately could control the longitudinal length of oil slick efficiently for sudden oil pollution accidents. Because of oil slicks itself spreading, the final longitudinal length is similar in conditions of different closing time.(2) A two-dimensional hydrodynamic and oil spilled numerical model of channel with bifurcations was established to simulate the oil separate characteristics in the bifurcations in conditions of different flux ratio, velocity ratio and width ratio of rivers. The oil spread time effect and wind effect on the oil separate characteristic were studied. Time revised coefficient Kt was obtained to reflect the effect of spreading time on the oil separate characteristics. When spread time t is less than T,Kt=aln(t)+b, in which a, b and T are parameters related to the width of the main channel. The wind effect on the oil separate characteristic is related to the wind speed, the wind direction and wind field time. The oil separate ratio formula driven by water was obtained, which is related to the flux rate Q1/Q0, the velocity rate V1/V0 and the width rate(B1/B0)0.5. The oil separate ratio formula is Koil=1.06KQVB0.5(3) A three-dimensional numerical model for oil submergence was established which was verified by physical model test. The depth of check sluice under water surface to control oil submergence in conditions of different velocities which were below 0.7 m/s was obtained by numerical simulation analysis. When the velocity is between 0.6 m/s and 0.7 m/s, the depth of check sluice should not less than 0.5 m. When the velocity is between 0.5 m/s and 0.6 m/s, the depth of check sluice should not less than 0.4 m. When the velocity is below 0.5 m/s, the depth of check sluice should not less than 0.35 m. Oil submergence in front of inversed siphon import in different hydraulic conditions was also simulated by which the condition of controlling oil submergence was obtained. The oil slick would not submergence if there were no vortexes.The results of this paper would provide technical support for the emergency control and disposal.