Prediction of Fretting Wear Depth for Steam Generator Tubes Based on Various Types of Wear Scars

Abstract

Calculations of fretting wear depth due to the turbulence excitation around steam generator tubes, for various wear scars, are carried out numerically. Four typical wear topologies, namely, round-, crescent-, flat-, and oblique-shaped wear scars, are adopted to represent the configuration of the wear volume. Oblique wear shows the most severe case for the wear time history, whereas both round-and crescent-shaped wears have smaller increasing rates of wear histories than flat-or oblique-shaped wears. It can be estimated that a high cross flow, around the U-bend region of the steam generator tube, significantly enhances the wear phenomena because the basic wear scar, at the contact point between the tube and its support, is flat or oblique. Parametric studies on the inclined angle and radial clearance are also carried out for oblique and crescent wear shapes.