Two‐ and Three‐Dimensional Numerical Experiments Representing Two Limiting Cases of an In‐Line Pair of Finger Seal Components

M J Braun,V V Kudriavtsev,B M Steinetz,M P Proctor

doi:10.1155/s1023621x03000162

Abstract

The work presented here concerns the numerical development and simulation of the flow, pressure patterns, and motion of a pair of fingers arranged one behind the other and axially aligned in line. The fingers represent the basic elemental component of a finger seal and form a tight seal around the rotor. Yet their flexibility allows compliance with rotor motion and, in a passive‐adaptive mode, compliance with the hydrodynamic forces induced by the flowing fluid. Although this article does not treat the actual staggered configuration of a finger seal, the in‐line arrangement represents a first step toward that final goal. The numerical two‐dimensional (axial‐radial) and three‐dimensional results presented herein were obtained using a commercial package (CFD‐ACE+). Both models use an integrated numerical approach, which couples the hydrodynamic fluid model based on Navier‐Stokes equations to the solid mechanics code that models the compliance of the fingers.

Highlights

The work presented here concerns the numerical development and simulation of the flow, pressure patterns, and motion of a pair of fingers arranged one behind the other and axially aligned in line
GEOMETRY OF THE FINGERS We present here a detailed layout of the three-dimensional computational domain and its construction, with only the mention that the grid used for the two-dimensional simulation was obtained by eliminating the circumferential coordinate from the three-dimensional simulation
The two-dimensional approach considers an axisymmetrical model of rotational flow, with rotational speed specified on the shaft/runner surface

Summary

Introduction

The work presented here concerns the numerical development and simulation of the flow, pressure patterns, and motion of a pair of fingers arranged one behind the other and axially aligned in line. The numerical two-dimensional (axial-radial) and three-dimensional results presented were obtained using a commercial package (CFD-ACE+) Both models use an integrated numerical approach, which couples the hydrodynamic fluid model based on Navier-Stokes equations to the solid mechanics code that models the compliance of the fingers. The fingers’ compliance allows both axial and radial adjustment to rotor excursions without damage to the integrity of the seal Their potential lifting capability eliminates the wear factor, considerably increasing their life span over that of rigid seals.

Objectives

Results

Conclusion