Numerical Study On Fluid Transients In Cooling-Water System Of Thermal Power Plants

With the dramatic economic growth in China in recent decades, the demand for electricity supply is constantly increasing, which results in a rapid development of the power generation industry. The thermal power plant (TPP) has been a preferred option in developing countries for its less investment and shorter construction period. In modern TPPs, the unit capacity has been increased significantly and thus the cooling system is getting more and more complicated. To improve the system reliability, the issues about waterhammer occurrences and their protection measures in the cooling system are being paid an intensive attention within both industry and academic domains. Meanwhile, the energy consumption of the expanded cooling system could directly affect the annual cost. Therefore, the cooling system becomes an important component in the power plant in terms of system operation safety and cost.Based on the literature review and combined with several real projects, such as, "Transient Analysis for the Cooling-Water System of Jiaxing Power Plant", etc., a comprehensive research on numerical analysis of transient flows in TPPs' cooling-water system is carried out; and some significant exploration on system optimization design and economical operation is made.Firstly, the different types of system boundary conditions are analyzed and corresponding mathematical models are developed. The numerical analyses of conventional transients are performed, and the calculation results are applied to engineering design and are confirmed in the engineering observations.Secondly, using the calculation examples from the real projects, the effects of the design parameters, including the cross-sectional area of the siphon-well, the elevation of overflow weir and the location of siphon-well in the system, on the performance of transient flows are analyzed and the basic fundamental in siphon-well design is proposed; the mathematical model of a special type of siphon-well (with air-check) is developed and the accuracy is verified by calculation examples.Thirdly, the transition between various operation conditions of the condenser is studied. And the expression is yield, which expressed the cooling water temperature rise and the system circulation water volume. The impact of circulating water volume on the operation condition of the condenser is analyzed preliminarily. There are important meanings in studying systematic economical operation further in the future in this achievement.Finally, some limitations and unsolved issues are addressed, and the problem correlated to the further research associated with transient analysis in cooling system are suggested.This research was funded by the National Natural Science Award (No. 50179008). Here, I would like to express my deep gratitude.