On the Mechanism of Head Breakdown in Cavitating Inducers

Abstract

The mechanism of head breakdown in cavitating inducers, as affected by thermodynamic properties of the pump fluid and scale effects, is discussed. The approach taken by other investigators is presented, and the limitations to cavitation scaling are examined in relation to experimental data. Because of the incomplete correlation with test data observed, a hypothesis is introduced which relates the head breakdown process to an acoustic shock phenomenon at the point of the leading-edge blade cavity collapse. Also, an integrated model for the cavitating cascade blade is developed, which makes it possible to correlate the potential flow cavity cascade model with the influence of thermodynamic properties, the thermostatic approach, and application of bubble dynamic studies to understand how suction performance is limited by inlet pressure.