Research On Hydraulic Performance Of A New Type Air Vessel In Long-distance Pressure Water Transfer System

With the development of society,the complexity and diversity of long-distance pressure water transfer project are increasing,and the problem of water hammer protection is becoming increasingly prominent.Air vessel is widely used in water transfer project.It is of great significance to select appropriate measures to protect water hammer according to the project conditions.In this paper,the water hammer protection of air vessel in long-distance pressure water transfer project is studied,a new type of air vessel is proposed,and its hydraulic performance is discussed,the main contents are as follows:(1)In this paper,the research progress of air vessel in numerical simulation,joint protection,structural type,layout scheme,parameter optimization and so on is reviewed.The characteristic method and the solution process of basic boundary conditions for water hammer calculation are deduced.(2)The limitation of conventional air vessel is analyzed.Based on the conventional air vessel,the adjustable central dipping tube air vessel is put forward,and the mathematical model of the adjustable central dipping tube air vessel is established.(3)By comparing the physical model experiment with the numerical simulation,the feasibility of the mathematical model to simulate the hydraulic transition process of water transfer system is verified.(4)Based on the actual project,combined with numerical simulation calculation,the water hammer protection characteristics of the conventional air vessel and the adjustable central dipping tube air vessel are studied and compared.The results show that the adjustable central dipping tube air vessel takes into account both the structure and protection performance,and is more economical than the conventional air vessel.(5)Based on the comparative analysis of the structural parameters such as the length,diameter of central dipping tube and restricted orifice of the adjustable central dipping tube air vessel,the influence of the parameter change on the hydraulic performance of the adjustable central dipping tube air vessel is studied.The results show that the longer the length of the central dipping tube,the better the water hammer protection effect,the change of the diameter of the central dipping tube has little effect on the water hammer protection effect,there is a range of the restricted orifice,in which the water hammer protection effect is the best.(6)Based on the research results of theoretical analysis and numerical simulation,the parameters of the adjustable central dipping tube air vessel are optimized,and the problems that need to be further studied are put forward.