Bounds of cavitation inception in a creeping flow between eccentric cylinders rotating with a small minimum gap

TL;DR

This study experimentally determines the conditions under which cavitation occurs in a creeping flow between eccentric cylinders with a small gap, identifying bounds related to geometric and rotational parameters.

Contribution

It provides new experimental bounds for cavitation inception in eccentric cylinder flows, highlighting the influence of minimum gap and rotation speed.

Findings

Cavitation bubbles form near the downstream minimum gap.

Cavitation occurs within a specific parameter region bounded by an inception curve.

High rotation velocities can induce cavitation even at small gaps.

Abstract

Bounds of cavitation inception are experimentally determined in a creeping flow between eccentric cylinders, the inner one being static and the outer rotating at a constant angular velocity, {\Omega}. The geometric configuration is additionally specified by a small minimum gap between cylinders, H, as compared with the radii of the inner and outer cylinders. For some values H and {\Omega}, cavitation bubbles are observed, which are collected on the surface of the inner cylinder and equally distributed over the line parallel to its axis near the downstream minimum gap position. Cavitation occurs for the parameters {H,{\Omega}} within a region bounded on the right by the cavitation inception curve that passes through the plane origin and cannot exceed the asymptotic threshold value of the minimum gap, Ha, in whose vicinity cavitation may occur at H<Ha only for high angular rotation velocities.