Theoretical Analysis for Passage and Exit Flow of Two Dimensional Centrifugal Impeller with Leading Edge Cavitation. (Effects of Blade Number and Blade Angle)

A theoretical analysis of passage and exit flow of a two dimensional logarithmic impeller with leading edge cavitation by using the singularity method is performed. In the wide parametric calculation, the flow features of impeller passage such as the cavity characteristics and the distributions of the relative velocity, and the static pressure are clarified with the flow rate, the blade number and the blade angle. And in the case of both back and face cavitation, the distributions of the static pressure, relative flow angle and the slip velocity at the impeller exit are also clarified with the blade number and the blade angle. And further, the changes of the slip factor and the impeller efficiency by the cavitation are shown to be determined from the simple formula. Finally, a comparison of the present calculated results with the existing experimental data and former calculated results is made.