Abstract: At full and over load operating points, some Francis turbines experience strong self-excited pressure and power oscillations. These oscillations are occuring due to the hydrodynamic instability of the cavitating fluid flow. In many cases, the amplitude of such pulsations may be reduced substantially during the turbine operation by the air injection/ admission below the runner. Such an effect is investigated numerically in the present work. To this end, the hybrid one-three-dimensional model of the flow of the mixture “liquid−vapor” in the duct of a hydroelectric power station, which was proposed previously by the present authors, is augmented by the second gaseous component  the noncondensable air. The boundary conditions and the numerical method for solving the equations of the model are described. To check the accuracy of computing the interface “liquid−gas”, the numerical method was applied at first for solving the dam break problem. The algorithm was then used for modeling the flow in a hydraulic turbine with air injection below the runner. It is shown that with increasing flow rate of the injected air, the amplitude of pressure pulsations decreases. The mechanism of the flow structure alteration in the draft tube cone has been elucidated, which leads to flow stabilization at air injection.

Cite: Chirkov D.V. , Shcherbakov P.K. , Cherny S.G. , Skorospelov V.A. , Turuk P.A.
Numerical investigation of the air injection effect on the cavitating flow in Francis hydro turbine
Thermophysics and Aeromechanics. 2017. V.24. N5. P.691-703. DOI: 10.1134/S0869864317050055 WOS Scopus OpenAlex

Original: Чирков Д.В. , Щербаков П.К. , Черный С.Г. , Скороспелов В.А. , Турук П.А.
Численное исследование влияния вдува воздуха на кавитационное течение в радиально-осевой гидротурбине
Теплофизика и аэромеханика. 2017. Т.24. №5. С.711-723.

Identifiers:

Web of science:	WOS:000418306000005
Scopus:	2-s2.0-85038882716
OpenAlex:	W2775909038

Citing:

DB	Citing
Scopus	22
OpenAlex	20
Web of science	16

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