Eccentric Brush Seal Assembly for Uniform Rotor Clearance
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Brush seals in gas turbine engines often experience radial offset due to manufacturing and assembly tolerances, leading to non-uniform circumferential clearance, increased fluid leakage, heat generation, and potential instability or failure of rotating components.
Innovation Solution
The introduction of an annular plate assembly with eccentricities at the radially inner or outer diameters ensures the bristle bore is concentric with the component outer diameter, providing uniform clearance and reducing interference, thereby minimizing leakage and heat generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the brush seal is designed to operate with radial offset due to manufacturing and assembly tolerances, then the brush seal can be installed with standard tolerances, but non-uniform circumferential clearance is present between the bristles and rotating component leading to increased fluid leakage
Solution Approach 1:
The patent applies asymmetry by intentionally introducing an eccentricity between the bristle pack bore and the outer diameter of the brush seal. This asymmetric configuration compensates for the radial offset that occurs during installation, ensuring that the bristles maintain a more uniform circumferential clearance with the rotating component throughout the rotation cycle, thereby reducing fluid leakage despite standard manufacturing tolerances
2Ease of manufacture
If the brush seal operates with non-uniform circumferential clearance, then installation is simpler with standard tolerances, but increased interference in certain regions leads to increased heat generation due to higher contact pressure and frictional torque
Solution Approach 1:
The eccentricity introduced in the bristle pack bore creates an asymmetric geometry that compensates for installation radial offset. This ensures more uniform distribution of contact pressure and frictional torque around the rotating component, preventing localized regions of excessive heat generation while maintaining compatibility with standard installation tolerances
3Ease of manufacture
If the brush seal operates with increased circumferential clearance in opposite direction, then manufacturing and assembly is easier, but increased fluid leakage through the increased circumferential clearance occurs leading to increased internal losses and reduced thermal efficiency
Solution Approach 1:
The patent introduces an eccentricity between the bristle pack bore and outer diameter that creates an asymmetric clearance distribution. This asymmetric configuration compensates for the radial offset during rotation, ensuring that the circumferential clearance remains more uniform throughout the rotation cycle, thereby preventing regions of excessive clearance that would lead to increased fluid leakage and reduced thermal efficiency
4Manufacturing precision
If the brush seal operates with increased interference between bristles and rotating component, then standard manufacturing tolerances can be used, but increased contact pressure leads to increased heat generation causing local thermal growth and potential instability or failure of rotating component
Solution Approach 1:
The eccentricity in the bristle pack bore creates an asymmetric geometry that compensates for radial offset during installation. This ensures more uniform contact pressure distribution between the bristles and rotating component, preventing localized regions of excessive contact pressure that would cause thermal growth and potential instability or failure of the rotating component
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration reduces fluid leakage and heat generation, increasing the operating life of the bristles and preventing instability or failure of the rotating components by maintaining uniform clearance and reducing high contact pressure.
Implementation Method 1
The bristles of the brush seal may be in a sliding relationship with a rotating component
Implementation Method 2
increased heat generation due to higher contact pressure
Implementation Method 3
an increased fluid leakage through the increased circumferential clearance
Implementation Method 4
The introduction of an annular plate assembly with eccentricities at the radially inner or outer diameters ensures the bristle bore is concentric with the component outer diameter
Implementation Method 5
increased heat generation due to higher contact pressure and higher frictional torque
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A brush seal (400, 600, 700, 900, 900-1, 1000) includes an annular plate assembly (402, 602, 702, 902, 902-1, 1002) defining a radially inner diameter (D2, D2-1, D2-2, D2-4, D2-5, D2-6, D2-7) having an inner central axis (A2, A2-1, A2-2, A2-4, A2-5, A2-6, A2-7) and a radially outer diameter (D3, D3-1, D3-2, D3-4, D3-5, D3-6, D3-7) having an outer central axis (A3, A3-1, A3-2, A3-4, A3-5, A3-6, A3-7). The inner central axis (A2, A2-1, A2-2, A2-4, A2-5, A2-6, A2-7) and the outer central axis (A3, A3-1, A3-2, A3-4, A3-5, A3-6, A3-7) are spaced apart from each other by an offset (O1, O2, O3, O4, O5, O6, O7), such that the radially inner diameter (D2, D2-1, D2-2, D2-4, D2-5, D2-6, D2-7) and the radially outer diameter (D3, D3-1, D3-2, D3-4, D3-5, D3-6, D3-7) are eccentric with respect to each other. The brush seal (400, 600, 700, 900, 900-1, 1000) further includes a bristle pack (408, 608, 708, 908, 908-1, 1008). The bristle pack (408, 608, 708, 908, 908-1, 1008) includes a plurality of bristles (410, 610, 710, 910, 910-1, 1010) defining a bristle bore (412, 612, 712, 912, 912-2, 1012) having a bristle bore central axis (A4, A4-1, A4-2, A4-4, A4-5, A4-6). The bristle bore central axis (A4, A4-1, A4-2, A4-4, A4-5, A4-6) is aligned with the inner central axis (A2, A2-1, A2-2, A2-4, A2-5, A2-6, A2-7) and the bristle bore central axis (A4, A4-1, A4-2, A4-4, A4-5, A4-6) is offset from the outer central axis (A3, A3-1, A3-2, A3-4, A3-5, A3-6, A3-7). Moreover, the brush seal (400, 600, 700, 900, 900-1, 1000) is disposed around a rotating component (106). The bristle bore central axis (A4, A4-1, A4-2, A4-4, A4-5, A4-6) is aligned with a component axis (A1) of the rotating component (106) and the bristle pack (408, 608, 708, 908, 908-1, 1008) engages with the rotating component (106).