Wear of Brush Seals: Background and New Modeling Approach

It has been observed that the geometry of a brush seal has a significant effect on the sealing performance. However, the relationship between rotordynamic coefficients and geometry factors of the brush seal itself are rarely considered. In this article, the rotordynamic coefficients of a typical single-stage brush seal for different geometries and operating conditions were numerically analyzed using CFD RANS solutions coupled with a non-Darcian porous medium model. The reaction force which plays an essential role in rotordynamic coefficients was obtained by integrating the dynamic pressure distribution. The influence of the bristle pack thickness, fence height, clearance size and other working condition parameters on aerodynamic force, stiffness coefficients, and damping coefficients of brush seal were presented and compared. In addition, the effects of various geometric configurations on pressure and flow features were also discussed.

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“…Some relevant literature can be found in [4][5][6][7]. Figure 1 shows schematic of a typical brush seal.…”

Section: Introductionmentioning

confidence: 99%

Influence of Geometry on Rotordynamic Coefficients of Brush Seal

Yuan

Dowell

Chen

et al. 2017

International Journal of Turbo &Amp; Jet-Engines

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“…[1])). According to Aksit and Tichy [2], the wear of brush seals, similarly to other sliding contacts, depends on three ma in factors:…”

Section: Introductionmentioning

confidence: 99%

Analysis of Heat Flux Distribution during Brush Seal Rubbing Using CFD with Porous Media Approach

2021

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This paper discusses the question of heat flux distribution between bristle package and rotor during a rubbing event. A three-dimensional Computational Fluid Dynamics (3D CFD) model of the brush seal test rig installed at the Institute of Thermal Turbomachinery (ITS) was created. The bristle package is modelled as a porous medium with local non-thermal equilibrium. The model is used to numerically recalculate experimentally conducted rub tests on the ITS test rig. The experimentally determined total frictional power loss serves as an input parameter to the numerical calculation. By means of statistical evaluation methods, the ma in influences on the heat flux distribution and the maximum temperature in the frictional contact are determined. The heat conductivity of the rotor material, the heat transfer coefficients at the bristles and the rubbing surface were identified as the dominant factors.

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“…6 From this perspective, the development of brush seals for gas turbine engines represents a promising method that satisfies both the aforementioned criteria. 7,8 The working principle of the brush seals consists of sealing the oil by means of the multitude of curved bristles made from carbon, steel, or other materials that slide together on the rotor surface during the operation of the engine being positioned very close to each other. The analysis of the behavior of the bristles during their operation provides important information for their dimensional and material selection.…”

Section: Introductionmentioning

confidence: 99%

Mathematical model of brush seals for gas turbine engines: A nonlinear analytical solution

Changizi

Stiharu

Outirba

et al. 2021

Advances in Mechanical Engineering

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Presented herein is a mathematical model employing differential equations formulation for brush seals used in gas turbine engines. These components are used to seal the bearing chamber from the environment and reduce the loss of lubricant in the atmosphere, ensuring a MTBR long enough to have required the change the seals only during the engine overhaul operation. The model assumes a single curved bristle loop in the form of a curved-bridge beam subjected to the influences of complex external loads (static and dynamic). Further, a model for clustered bristles is proposed. Specifically, the static forces acting on the curved-bridge beam include the weight of the oil capillary attached to the beam, the weight of the beam itself, the capillary force developed between the surfaces of the bristles in the brush and the temperature gradient. The dynamic forces include the leakage oil pressure and the rotation of the shaft. This complex loading induces a nonlinear large deflection on the curved-bridge beam. Also, the temperature gradient present on the bristles during the gas turbine engine operation generates a change in the geometry of the beam and in the magnitude of the forces acting on the bristles modeled as beams. In the present model, the weights are assumed as uniformly distributed forces on the surface of the beam while the capillary forces and the force generated by the rotating shaft are considered to be non-uniform. The equation expressing the curvature of the beam under general loading force is developed and one can choose the appropriate method of solving the generated differential equation after the expression of the general force is defined. Hence, the ordinary differential equation describing the nonlinear large deflection of the curved-bridge beam will be derived using general nonlinear elasticity theory.

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Wear of Brush Seals: Background and New Modeling Approach

Cited by 12 publications

References 11 publications

Influence of Geometry on Rotordynamic Coefficients of Brush Seal

Influence of Geometry on Rotordynamic Coefficients of Brush Seal

Analysis of Heat Flux Distribution during Brush Seal Rubbing Using CFD with Porous Media Approach

Mathematical model of brush seals for gas turbine engines: A nonlinear analytical solution

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