Estimate of the radial unsteady forces acting on a cavitating inducers from casing pressure measurements

This paper presents a methodology to estimate the radial forces acting on a cavitating inducers from the pressure signals measured at the machine casing by a set of sensors installed at different axial and azimuthal locations. The results of these methodologies are validated on the experimental data obtained on a water loop dedicated to the study of the performance and the unsteady phenomena in a cavitating inducer. The pressure and efforts are traced by unsteady pressure sensors on the pump casing and by a 6 components balance measuring efforts on the inducer shaft. For the validation, tests at two different rotating velocities were conducted during which a continuous pressure drop was imposed to the inducer, starting from a non cavitating operating point at given rotating speed and flow rate, down to a 20% pressure drop.