The mechanism of pressure vibrations occurring in hydrodynamic generators

A numerical investigation of the effect of the cavitation on the process of occurrence of vibrations in hydrodynamic generators was conducted. The set including the equations of continuity and Navier Stokes, those of the two-parametrical model of turbulence, and the equation of transport of vapor mass fraction for the cavitation model was used. The flow was considered as axisymmetrical. The calculation was carried out for the cylindrical channel of 3.5 mm radius and 35 mm length. It was assumed that the working fluid (water) is fed through four tangential apertures. Due to such feeding, the flow was twisted. The pressure distributions in the channel and chamber at the moment of time corresponding to the lowest pressure at the axis in the cross section of input apertures and at the moment corresponding to the peak show that the most intense pulsations of pressure are observed at the initial portion of the channel. In the axial zone, the pressure decreases due to the centrifugal effects caused by flow twisting.