Fabien Wahl

Effects of Alternate Leading Edge Cutback on Unsteady Cavitation in 4-Bladed Inducers

A set of 4-bladed inducers with various amounts of cutback was tested with the aim of suppressing the rotating cavitation by applying alternate leading edge cutback. Unsteady cavitation patterns were observed by means of inlet pressure measurements and highspeed video pictures. The region with the alternate blade cavitation and asymmetric cavitation were enlarged with the increase of the amount of the cutback. As a result, the region with the rotating cavitation was diminished. At low flow rate, two types of alternate blade cavitation were found as predicted theoretically on 4-bladed inducer with smaller uneven blade length. One of them is with longer cavities on longer blades, and the other is with longer cavities on shorter blades. Switch was observed in these alternate blade cavitation patterns depending whether the cavitation number was increased or decreased. For an inducer with larger amount of cutback, the rotating cavitation and cavitation surge were almost suppressed as expected for a wide range of flow rate and cavitation number, although the cavitation performance was deteriorated

Theoretical Analysis of Cavitation in Inducers with Uneven Length Blades : (2nd Report, Effects of the Amount of Cutting Back)

The present report describes about the effects of the amount of the alternate cutting back of the leading edges on the steady cavitation, its stability and the onset region of rotating cavitation. It was found that, by increasing the amount of cutting back, we can increase the range of cavitation number with stable cavitation and diminish the onset region of rotating cavitation.

Theoretical analysis of cavitation in inducers with uneven length blades (2nd report, effects of the amount of cutting back)

The present report describes about the effects of the amount of the alternate cutting back of the leading edges on the steady cavitation, its stability and the onset region of rotating cavitation. It was found that, by increasing the amount of cutting back, we can increase the range of cavitation number with stable cavitation and diminish the onset region of rotating cavitation.