Water hammer effect in the spiral case and penstock of Francis turbines

International Conference on Applied Sciences 2016

Pepa, D.^1 ; Ursoniu, C.^2 ; Gillich, G.R.^2 ; Campian, C.V.^2

UCM Resita, Department of Mechanical Engineering, Golului str., no.1, Resita

320053, Romania^1

Eftimie Murgu University of Resita, Department of Engineering and Management, Piata Traian Vuia str., no. 1-4, Resita

320085, Romania^2

关键词: Analytical calculation;    Calculation algorithms;    Increase in pressure;    Method of calculation;    Performance tests;    Pressure increase;    Water hammer effects;    Water hammer phenomenon;   

Others  :  https://iopscience.iop.org/article/10.1088/1757-899X/163/1/012010/pdf
DOI  :  10.1088/1757-899X/163/1/012010

来源: IOP

【 摘 要 】

Sudden pressure increases in the penstock or spiral case of a hydraulic turbine are the effect of sudden flow variation that occur during transient processes of type opening / closing or load rejection of the hydro unit. The consequence of the pressure rise in the spiral case and penstock is the water hammer phenomenon, whose effects can be devastating in some cases, up to breaking pipes and calamities produced in the area. This paper aims to analyze the method of calculation of the maximum pressure values that might occur in load rejection situations to a hydraulic turbine, in spiral case and in penstock, conditioned by the limiting of the values of the over speed and measures of limiting the increase in pressure in conjunction with limiting the increase in speed in these specific processes. As an example, we studied and analyzed the situation of a hydroelectric power plant equipped with a 7.8 MW Francis turbine without pressure regulator and the inflow surge. The results of analytical calculation overlaid on the experimental measurements performed during the performance tests of the hydro unit lead to the conclusion that the calculation algorithm proposed has been chosen correctly and the 2-stage closing law of the wicket gate promoted in this case is effective in such situations.