Numerical simulation of full load surge in Francis turbines based on three-dimensional cavitating flow model

27th IAHR Symposium on Hydraulic Machinery and Systems

Chirkov, D.^1 ; Panov, L.^1 ; Cherny, S.^1 ; Pylev, I.^2

Institute of Computational Technilogies SB RAS, Novosibirsk, Russia^1

OJSC Power Machines LMZ, St-Petersburg, Russia^2

关键词: Acoustic equation;    Cavitating flow;    Cavitation model;    Numerical parameters;    Power station;    Self excited oscillation;    Systems of equations;    Unsteady RANS;   

Others  :  https://iopscience.iop.org/article/10.1088/1755-1315/22/3/032036/pdf
DOI  :  10.1088/1755-1315/22/3/032036

来源: IOP

【 摘 要 】

The two-phase 1D-3D model of full load surge, presented previously by the authors, is applied to simulation of self-excited oscillations in prototype power station. The model consists in 1D hydro-acoustic equations for the penstock domain, and 3D two-phase unsteady RANS equations for turbine domain, including the cavitating flow in the draft tube. Both systems of equations are linked together by pressure and discharge at the penstock-turbine interface and solved simultaneously. To demonstrate the work of the model over-load pressure pulsations are simulated for high head prototype power plant. The influence of numerical parameters is investigated. It was shown that the choice of cavitation model has a strong effect on the amplitude of pulsations. The structure of the vapor cavity is investigated. The computed frequency is compared to the results of 1D model and with experimental data. Amplitudes and frequencies of the pulsations agree well with experiment, showing the potential of the method to predict full-load surge.