Slanted Perforated Plate Gas Turbine Combustor Damping
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Solution Overview
Problem
Existing damping devices for gas turbine combustors, such as Helmholtz dampers and perforated plate dampers, struggle to effectively damp a broadband range of combustion pressure oscillations while minimizing the impact on the space available outside the combustor, as they either require additional volumes and necks or have limited frequency damping capabilities.
Innovation Solution
A slanted perforated plate damper with varying radial extent and thickness along the axial and circumferential combustor directions is used, allowing for a single damping volume to effectively damp a broad frequency range with minimal space impact, utilizing advanced manufacturing processes to create channels that optimize frequency response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional Helmholtz dampers or perforated plate dampers are used to damp combustion pressure oscillations, then damping capability is improved, but the space occupied outside the combustor increases
Solution Approach 1:
The damping device is nested within the existing combustor structure, with the damping volume positioned inside the combustor and the perforated plate forming part of the liner assembly. This nesting approach allows the damper to utilize the combustor's internal space rather than requiring additional external volume, directly resolving the contradiction between damping capability and space occupation.
Solution Approach 2:
The invention transitions from traditional three-dimensional volumetric dampers to a two-dimensional perforated plate configuration that spans across the combustor. By using the plate's surface area and the acoustic path through the perforations rather than relying on large volumetric structures, the design achieves effective damping while minimizing the space occupied outside the combustor.
2Adaptability or versatility
If multiple volumes and necks are added to extend the damping frequency range, then broadband damping is improved, but the device complexity and space requirements increase
Solution Approach 1:
The perforated plate is designed with non-uniform perforation distribution, where the hole size, spacing, and density vary across different regions of the plate. This local variation in perforation characteristics allows the single plate structure to provide damping across a broad frequency range, eliminating the need for multiple separate volumetric dampers with different neck configurations.
Solution Approach 2:
The single perforated plate serves multiple functions simultaneously: it acts as a structural component of the combustor liner, provides acoustic damping across various frequencies, and defines the flow path for the damping mechanism. This multi-functionality replaces what would traditionally require multiple specialized components, reducing overall device complexity while maintaining broadband damping capability.
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
The solution provides a compact damping device capable of damping a wide range of frequencies with minimal space intrusion, enhancing the operational stability of gas turbines by reducing mechanical damage from pressure oscillations.
Implementation Method 1
A traditional damper comprises a damper volume fluidly connected to the combustion chamber that acts as a resonator volume
Implementation Method 2
the perforated plate is configured for fluidly connecting the combustion chamber to the damping volume for damping pressure fluctuations
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A gas turbine for power plant; the gas turbine (1) having an axis (9) and comprising: a compressor sector (2) for compressing ambient air; a combustor sector (4) for mixing and combusting the compressed air with at least a fuel; the combustor sector (4) comprises at least a liner (7, 26) defining a combustion chamber (6, 21, 23) having an axial direction (A) and a circumferential direction (C); at least a turbine sector (3) for expanding the combusted hot gas flow leaving the combustors (4) and performing work on a rotor (8); at least a damping device (28) arranged outside the combustion chamber (6, 21, 23) and comprising a damping volume (29) and a perforated plate (30) configured for fluidly connecting the combustion chamber (6, 21, 23) to the damping volume (29) for damping pressure fluctuations generated inside the combustion chamber (6, 21, 23); wherein the perforated plate (30) is slanted shape so that the radial thickness of the perforated plate (30) varies along the axial combustor direction (A) and/or along the circumferential combustor direction (C).