Research On Improvement Of Water Hammer Calculation In Pressure Pipeline Of Hydropower Station

The study of water hammer begin in the 19th century,it has long history.This hydraulic phenomenon which occurs in the pressure pipes has a great deal of harm.It is inevitable in hydropower station and pump station.The high and low alternating water hammer pressure in pipeline may cause the violent vibration and noise,deformation,serious when even will make pipe burst.Although the water hammer phenomenon has been a history of 100 years of research,but it still exist problems of classical theory,has not been solved.To want to get more realistic and accurate results,you need to improve the classic theory of water hammer,so as to lay the foundation for later research content.Firstly,this paper introduce the classical theory of water hammer in detail,including the analysis of water hammer phenomenon and its classification are introduced,and then the basic differential equations of the classical theory of the water is derived in detail,and point out the existing problems that the classical theory of water hammer fluid velocity head,did not consider the pipe that is bound to lead to inaccurate results.In order to solve this problem,this paper to derive the motion equation and continuity equation,and uses the characteristic line method for numerical calculation of this system of equations.In FORTRAN programming platforms,and draw the end section curve of water hammer pressure changing with the time.Although the calculation result is better than the result of classical theory,and relatively more accord with actual situation,but did not fundamentally solve the problem.Secondly,this paper reselect the research object,using the theorem of momentum and conservation of mass is rigorous derivation and established a new motion equation and continuity equation,combined with liquid elastic equations and pipe elastic equations,formed a new mathematical model.On the selection of numerical calculation method,because of the characteristic line method on this mathematical model is not very good use,therefore,this article selects the finite difference method for calculation,the difference equation is established and boundary conditions and initial conditions are provided,also in FORTRAN programming calculation platform,finally also draw the end section graph over time and the change rule of water hammer pressure.Finally,this paper compares the above three kinds of calculation results,found that establish a mathematical model of the second most conforms to the actual situation,also improved the classical theory of water hammer pipe internal water hammer pressure attenuation too slow,further verify the correctness and reliability of the mathematical model founded in this paper.The research content of this article is of great significance not only for the theory of water hammer,also has a guiding significance for practical engineering applications.