Experimental study of the effect of air injection on the pressure pulsations in the hydro turbine flow path under different operating conditions

Abstract

Abstract. The paper presents an experimental study of oscillatory response in the Francis turbine of hydraulic unit. The experiment was performed on large-scale hydrodynamic test-bench with impeller diameter of 0.3 m. The effect of air injection on the intensity of pressure pulsations was studied at the different regimes in the hydraulic unit. It was revealed that air delivery into the flow path system of the turbine results in almost two-fold reduction of pressure pulsations, but for optimal regimes, there is an increase in pressure pulsations.

A novel electromechanical system for guide vane adjustment in a small turbine test rig

“…Over the years, various methodologies were adopted to overcome the adverse effects, like reduction in detrimental effects of the rotating vortex rope (RVR) or mitigate the RVR. Many investigations, generally classified as passive/geometric modifications [11][12][13] and active/fluid injection modifications [14][15][16][17], were performed experimentally and numerically to mitigate or reduce the flow instabilities using standard model test setups [18][19][20][21][22]. The rig is designed to focus on the draft tube flow instabilities like the formation of a rotating vortex rope (RVR) and its mitigation.…”