Investigation into the flow behavior of multi-stage brush seals

Brush seals have found increasing use in turbomachinery within the past decade due to their superior sealing performance and flexible nature. The flow characteristics and fundamental behavior of single brush seal are known. However, the flow behavior of multi-stage brush seal combined with labyrinth teeth still requires further research. This article presents a detailed investigation into flow behavior of multi-stage brush seal combined with labyrinth teeth for turbine applications. The leakage rate through a two-stage brush seal combined with labyrinth teeth was measured using the rotating test rig at three operating clearances and four rotational speeds. The leakage rate through the seal was also numerically predicted using Reynolds-averaged Navier–Stokes solutions coupled with non-Darcian porous medium approach. To predict the seal leakage more accurately, the clearance reduction resulted from rotor centrifugal growth was considered in brush seal flow calculations. The effects of rotational speeds and sealing clearance on the leakage performance of the two-stage brush seal were evaluated based on the experimental and numerical results. In addition, to obtain an insight into flow mechanisms of multi-stage brush seals, the leakage rate, flow field, pressure distribution of bristle pack, and aerodynamic force acting on bristle pack of four different types of multi-stage brush seals were also analyzed and compared.

[1]  J. Chew,et al.  Mathematical modeling of brush seals , 1995 .

[2]  Gervas Franceschini,et al.  The Development of a Large Radial Movement Brush Seal , 2012 .

[3]  John W. Chew,et al.  Experimental Investigation and Mathematical Modeling of Clearance Brush Seals , 1998 .

[4]  Yahya Dogu.  Investigation of Brush Seal Flow Characteristics Using Bulk Porous Medium Approach , 2005 .

[5]  Mahmut Faruk Aksit,et al.  Effects of geometry on brush seal pressure and flow fields-Part I: Front plate configurations , 2006 .

[6]  Terry V. Jones,et al.  Detailed Experimental Studies of Flow in Large Scale Brush Seal Model and a Comparison With CFD Predictions , 2000 .

[7]  V. V. Kudriavtsev,et al.  A Numerical Simulation of a Brush Seal Section and Some Experimental Results , 1993 .

[8]  V. V. Kudriavtsev,et al.  Model Developments for the Brush Seal Numerical Simulation , 1996 .

[9]  John W. Chew,et al.  Porosity Modeling of Brush Seals , 1997 .

[10]  F. Bayley,et al.  A Combined Experimental and Theoretical Study of Flow and Pressure Distributions in a Brush Seal , 1992 .

[11]  Bruce M. Steinetz,et al.  Sealing in Turbomachinery , 2006 .

[12]  L. H. Chen,et al.  AN ITERATIVE CFD AND MECHANICAL BRUSH SEAL MODEL AND COMPARISON WITH EXPERIMENTAL RESULTS , 1998 .

[13]  Zhenping Feng,et al.  Experimental and Numerical Investigations on the Leakage Flow Characteristics of the Labyrinth Brush Seal , 2012 .

[14]  Matthias Neef,et al.  Design Features and Performance Details of Brush Seals for Turbine Applications , 2006 .

[15]  Yahya Doğu,et al.  Evaluation of Flow Behavior for Clearance Brush Seals , 2008 .

[16]  Robert C. Hendricks,et al.  Brush Seal Leakage Performance With Gaseous Working Fluids at Static and Low Rotor Speed Conditions , 1992 .

[17]  P Helm,et al.  Calibration of porous medium models for brush seals , 2009 .

[18]  P. Basu,et al.  Advanced brush seal development , 1996 .

[19]  S. Ergun.  Fluid flow through packed columns , 1952 .