Experimental investigation of cavitation in a sudden expansion pipe

For sudden expansion pipes, experiments were carried out to study the cavitation inception for various enlargement ratios in high speed flows. The flow velocity of the prototype reaches 50 m/s in laboratory. The relationship between the expansion ratio and the incipient cavitation number is obtained. The scale and velocity effects are revealed. It is shown that Keller's revised formula should be modified to calculate the incipient cavitation number when the forecasted velocity of the flows in the prototype exceeds the experimental velocity.