On Experimental Considerations of the Relation between Runaway Speeds and Cavitation Phenomena of Kaplan Turbine

Abstract

Author performed a series of experiments with various Kaplan turbines to study cavitation phenomena against runaway speeds under various conditions and arrived at the following conclusions : (1) There are two different types of cavitation phenomena, the 1st and the 2nd types, each with its own aspect of cavitation bubbling and runawy speed. (2) In the case of the 1st type, there occurred the identical formation of cavitation bubbles on each of all blades of a runner, while in the 2nd type, the formation of bubbles on every other blades is identical, those on two adjacent blades are not alike. (3) Occurrence of the 1st type or the 2nd type of cavitation bubbles depends upon the value of cavitation co-efficient, number and angle of blades, guide-vane opening, etc., and in many cases the increase in number of blades results in the 2nd type formation of cavitation bubbles.