Study Of Numerical Simulation Of Hydraulic Transient Occurred In Water-Cooling System Of Thermal Power Plants

With the economy development of our society, the requirement for power energy become more and more. So thermal power plants augment increasingly. As the one of three big systems of thermal power plants, water-cooling system hold the balance. In order to ensure the safe run of water cooling-system of thermal power plants, it is necessary to analyze the hydraulic transient of water-cooling system, choose the appropriate measures to protect the system and set down reasonable projects.A real project of Jiang Ying power plant is applied in this paper on the basis of the characteristic method. Water-cooling system involves some embranchments, loops and pumps. In addition, there are condensers, siphon wells and work well in the system. All boundary conditions are taken into account in this paper. By predigesting condensers and disposing the pump' s full characteristic curve, the mathematical model is established, which includes pipelines, work well, pump rooms, condensers and siphon wells. Then, the hydraulic transient of water-cooling system is calculated. To prevent the harm of water hammer when opening pumps, it is researched emphatically how the water level of pump room changes for different projects of opening pump. Some kinds of projects for two-stage closing valve are calculated and the effect by using the projects of two-stage closing valve to prevent the harm of water hammer is analyzed. The least flux of condensers is calculated for different projects to check the safety of water supply. In order to ensure the safety of facilities, the relationship between water hammer and the run of units is analyzed and the most reversal speed of pumps is calculated. How the water level of pump room changes with different instances of ceasing pump is analyzed, to prevent pump station from being submerged. Besides, it is analyzed how the changes of GD2 of units and friction of pipelines influence the hydraulic transient of water-cooling system. All calculation and analysis provide the necessary gist and methods to prevent water-cooling system from the harm of water hammer, and rational advices for the safe, steady and economical run of water-cooling system.