Improvement of the performance of small-sized cavitating venturis by inserting obstacles

Cavitating Venturis are simple apparatus used as a flow meter over a broad range of mass-flow rates. The main objective of this work is to introduce obstacles in small-sized cavitating Venturis in order to increase their capacity by raising the critical pressure, i.e. widens the phase of the cavitating mode. Four configurations have been tested depending on the location of these obstacles. This study focused on investigating the numerical performance of cavitating Venturis with different downstream pressures by employing the k-? SST turbulence model and the Rayleigh-Plesset equation for modeling cavitation. The governing equations were solved using the finite volume method, employing the Rhie and Chow pressure-velocity coupling scheme. The results showed the void fraction and streamlines contours obtained on the symmetry plane. The mass-flow ratio was presented for all configurations and different pressure ratios. The study showed that the cavitating Venturis equipped with obstacles extend the phase of choked mode from 10.71% to 21.42% and that the best configuration correspond to the case where the obstacles are placed in the converging section.