Effect of Polymer Additives on Cavitation Development and Noise in Water Flow Through an Orifice

Abstract

The cavitation behavior and the shock pressure were experimentally investigated in dilute aqueous solutions of polymer flowing through an orifice, and the following facts were observed: (i) Very small quantities of polymer additives effectively suppressed both the inception and the development of cavitation, (ii) nonspherical cavitation bubbles were observed at any polymer concentration tested here, and the nonsphericity tended to increase with concentration, (iii) the spectral frequencies of shock pressures were principally confined within the audio frequency range. With an increase in concentration, the energy of the pressures drastically decreased and the frequency range shifted downwards.