Numerical Analysis of Anti Vortex Devices Performance to Suppress the Air Entraining Vortex in Pump Sump

Non-uniform swirling flow and air entraining vortex are among the important causes of reduction in efficiency of hydraulic machines such as pumps, turbines etc. A numerical simulation based study presented in this paper is to evaluate the effect of Anti Vortex Devices (AVD) in minimizing the effect of air entraining surface vortex in the intake section of centrifugal pump. In proposed methodology, Fast Fourier Transform (FFT) analysis is performed on the pressure fluctuation data, obtained from Large Eddy Simulation (LES) model. Numerical results are obtained for a rectangular sump with and without AVD. FFT analysis shows the presence of large and small eddies in the sump. Effectiveness of AVD, in breaking down the large eddies to prevent the formation of vortex, can be clearly observed in FFT results. Triangular and modified AVD performed effectively in reducing the air entraining surface vortex.