Brush Seal Performance in Turbomachinery Applications

Brush seals are advanced contact‐style seals that employ dense packs of fine bristles to reduce fluid leakage around rotating shafts in turbomachinery. Compared with conventional labyrinth seals, they maintain narrower clearances and adapt to transient shaft excursions, thereby enhancing efficiency and reducing parasitic flow losses. Performance depends on the interplay of bristle geometry, material properties, seal backing conditions and operating parameters such as pressure ratio and rotational speed. Critical concerns include wear of bristle tips, heat generation during rubbing events, aerodynamic forces induced by inlet swirl and dynamic interactions arising from rotor‐stator eccentricity. Research has progressed from empirical test rigs towards high‐fidelity computational models, combining computational fluid dynamics with porous media and finite element analyses. These studies have improved predictions of leakage flow rates, blow‐down behaviour and temperature fields, while guiding design modifications such as front-plate geometries or pre-swirl flow conditioning. Collectively, this work underpins the global adoption of brush seals in gas turbines, compressors and other rotating equipment, contributing directly to lower fuel consumption, reduced emissions and extended maintenance intervals.

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Brush Seal Performance in Turbomachinery Applications publication trend

The graph below shows the total number of articles in brush seal performance in turbomachinery applications across all publications each year (not limited to Nature Index journals).

Technical terms

Brush seal: A seal composed of flexible bristles mounted around a rotor to minimise leakage by maintaining a tight clearance between bristle tips and the rotating surface.

Porous media model: A computational approximation treating the brush pack as a porous medium to simulate fluid flow resistance and heat transfer without modelling individual bristles.

Rotor-stator eccentricity: Lateral displacement between the rotating shaft and stationary housing that induces uneven loading and deformation of the bristle pack.

Inlet swirl: Circumferential flow component entering the seal that can impose tangential forces on bristles and destabilise the seal pack.

Blow-down: The radial displacement of bristles under pressure differential, affecting the effective clearance and sealing performance.

References

1. Prediction of Leakage Flow Rate and Blow-Down in Brush Seals via 2D CFD Simulation with Porosity Correction. Applied Sciences (2024).
2. Wear and Leakage Behaviors of Brush Seal Considering Eccentricity and Radial Deformation. Energies (2023).
3. Effects of Front Plate Geometry on Brush Seal in Highly Swirling Environments of Gas Turbine. Energies (2021).
4. Flow Conditioning to Control the Effects of Inlet Swirl on Brush Seal Performance in Gas Turbine Engines. Frontiers in Energy Research (2022).
5. Temperature Field and Performance Analysis of Brush Seals Based on FEA-CFD and the Porous Medium of Anisotropic Heat Transfer Models. Energies (2023).