Annular Helmholtz Damper Liquid Drainage for Gas Turbine Combustors
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Solution Overview
Problem
Annular Helmholtz dampers for gas turbines face challenges with liquid collection and fuel risk, leading to inefficiency and potential deflagration, especially due to their large volume size and limited space for installation.
Innovation Solution
The annular Helmholtz damper design includes intermediate and by-pass purge holes and drain holes arranged radially outward to efficiently drain collected liquid from the main volume to the secondary volume, minimizing fluid accumulation and preventing hot gas ingestion, with the damper being an integral part of the combustor casing to optimize pulsation frequency damping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the damper volume is increased to damp low frequency pressure pulsations, then the damping effectiveness is improved, but the risk of liquid collection and fuel deflagration increases
Solution Approach 1:
The annular damping volume is divided into multiple segments by intermediate circumferential plates with intermediate necks, creating a multi-chamber structure that reduces liquid accumulation in each individual chamber while maintaining overall damping effectiveness for low frequency pressure pulsations
Solution Approach 2:
Intermediate drain holes are introduced as intermediary elements that facilitate liquid drainage from the damping volume, allowing liquid to be removed from the system while the damper continues to function for pressure oscillation damping
2Adaptability or versatility
If multiple Helmholtz dampers are connected to damp a large frequency bandwidth, then the frequency coverage is improved, but the device complexity and space requirements increase
Solution Approach 1:
Multiple damping functions are merged into a single annular damper structure by dividing the damping volume into multiple volumes with different resonance characteristics, allowing broad frequency bandwidth coverage without requiring multiple separate damper units
Solution Approach 2:
The annular damper is designed to perform multiple damping functions across different frequency ranges through its multi-volume structure, making it a universal solution that replaces what would traditionally require multiple specialized dampers
3Reliability
If the damper volume is increased to improve low frequency damping, then the damping performance is improved, but the space available for installation is reduced
Solution Approach 1:
The damping volume is configured in an annular shape that utilizes the radial and axial dimensions around the combustor, efficiently using available three-dimensional space within the combustor can assembly to accommodate large damping volume without increasing external footprint
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 design reduces liquid collection and enhances evaporation, maintaining damper efficiency and preventing deflagration risks, while allowing for a more compact and effective damping solution that covers a broader frequency range.
Implementation Method 1
A traditional Helmholtz damper includes a damping volume that acts as a resonator volume and a neck fluidly connected to the combustion chamber. As explained above, the pressure oscillations generated due to the combustion need to be damped.
Implementation Method 2
The rear wall of common annular Helmholtz dampers comprises a plurality of passing purge holes positioned opposite to the main neck. Indeed, in order to prevent hot gas ingestion, purge air enters the damper volumes through the purge holes and exits through the main neck.
Implementation Method 3
The annular Helmholtz damper design includes intermediate and by-pass purge holes and drain holes arranged radially outward to efficiently drain collected liquid from the main volume to the secondary volume, minimizing fluid accumulation and preventing hot gas ingestion
Implementation Method 4
If the amount of the liquid collected inside the damper exceeds a certain percentage of the damper volume, the damper cannot work anymore with high efficiency until the liquid is evaporated
Data Source
Figure 1
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AI summary
An annular Helmholtz damper for a gas turbine can combustor, the annular Helmholtz damper having an axis and comprising: - an inner wall and an outer wall concentrically arranged with respect to the axis to define an annular damping volume arranged around a can combustor; - a front and a rear circumferential plate for closing upstream and downstream the annular damping volume; - at least one intermediate circumferential plate arranged between the front and the rear plates for dividing the annular damping volume in a main and a secondary volume; - at least one main neck passing at the inner wall and configured for fluidly connecting the main volume with the can combustor chamber; - at least one intermediate neck passing the intermediate circumferential plate configured for fluidly connecting the main volume with the secondary volume; - a plurality of purge holes passing the rear circumferential plate configured for entering purge air in the secondary volume; -a plurality of intermediate drain holes passing the intermediate circumferential plate configured for draining collected liquid from the main volume to the secondary volume.