Session: 27-07 Curvics, Brush Seals, and Multi-Layer SFDs in Rotordynamics

Paper Number: 128839

128839 - Rotordynamics of a Single-Stage Brush Seal in Isolation: The Effects of Variable Stiffness and Back Plate Geometry 

The brush seal offers a viable alternative to the labyrinth seal and is made of a bristle pack of fine-wire bristles which are welded together and sandwiched between a front and back plate. The front plate is designed to protect the bristles during installation and from incoming debris, as well as to minimise disruption to the bristle pack due to high swirl ratios. The back plate supports the pack and limits the deflection of the bristles when subject to upstream pressure. The pressure drop that the seal can withstand has been shown to be dependent on the bristle diameter and the overall thickness of pack. The length of the wire from the weld to the rotor impacts the stiffness of the bristle. A small change in this free length can double the seal stiffness.

There has been limited research regarding the rotordynamic stability of brush seals. This paper aims to experimentally characterise the leakage and rotordynamic performance of two different bristle diameters with both a flat and a pressure-relieved back plate. The high-speed rotating test rig at the University of Bath has been used to determine the leakage behaviour of the bristle pack and to characterise the effect of back plate geometry. The test facility was then utilised to study the dynamic characteristics of the brush seals with changes of excitation frequency, rotational speed and pressure drop.

Presenting Author: Josh Bird University of Bath

Presenting Author Biography: Josh is a PhD student at the University of Bath.

Authors:

Josh Bird University of Bath
Patrick Keogh University of Bath
Carl Sangan University of Bath
Aaron Bowsher Cross Manufacturing Company (1938) Ltd
Peter Crudgington Cross Manufacturing Company (1938) Ltd
James Scobie University of Bath