Multi-Volume Combustor Front Panel Dampers for Multi-Frequency Oscillations
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Solution Overview
Problem
Existing combustors in gas turbine engines experience acoustic pressure oscillations due to combustion heat, pressure, and system acoustics, leading to equipment damage and operational issues, requiring multiple acoustic dampers to address different frequencies.
Innovation Solution
Acoustic dampers with multiple volumes are integrated into the front panel of a combustor, featuring a damping chamber separated into first and second volumes, each damping a specific frequency, reducing the need for multiple dampers by absorbing a wider range of frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple acoustic dampers are used to damp acoustic pressure oscillations at different frequencies, then the damping effectiveness across multiple frequencies is improved, but the device complexity and number of components increases
Solution Approach 1:
The patent combines multiple acoustic dampers into a single integrated damper structure with multiple damping chambers (first and second damping chambers) that can simultaneously damp acoustic pressure oscillations at different frequencies. This merging approach maintains the damping effectiveness across multiple frequencies while reducing the number of separate damper components required in the combustion system.
Solution Approach 2:
The single acoustic damper structure is designed to perform multiple functions by incorporating different damping chambers with different acoustic characteristics. The first damping chamber targets specific frequency ranges while the second damping chamber addresses other frequency ranges, allowing one damper to serve multiple damping functions that would traditionally require separate dedicated dampers.
2Reliability
If the volume and neck dimensions of Helmholtz dampers are optimized for a specific target frequency, then the damping performance at that frequency is improved, but the ability to damp multiple frequencies simultaneously is reduced
Solution Approach 1:
The acoustic damper is segmented into multiple distinct damping chambers (first and second damping chambers) with different volume-to-neck ratio characteristics. Each chamber is optimized for different frequency ranges, allowing the overall damper structure to simultaneously target multiple frequency bands. This segmentation enables frequency-selective damping within a single integrated component.
Solution Approach 2:
Different regions of the acoustic damper structure have different acoustic properties tailored to specific frequency ranges. The first damping chamber has specific volume and neck dimensions optimized for certain frequencies, while the second damping chamber has different dimensions optimized for other frequencies. This local optimization of acoustic characteristics allows the damper to effectively address multiple frequency problems simultaneously.
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 multi-volume dampers effectively reduce acoustic oscillations across multiple frequencies, minimizing equipment damage and the number of required dampers, enhancing operational stability.
Implementation Method 1
The volume and neck dimensions of Helmholtz dampers are designed to damp acoustic pressure oscillations at one target frequency
Implementation Method 2
acoustic dampers, which can take the form of a quarter wave tube, a Helmholtz damper or a perforated screen, that absorbs the acoustic pressure oscillations reducing their amplitude
Data Source
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AI summary
An acoustic damper (400) for a rotary machine includes at least one wall (104), at least one inlet (420), at least one outlet (102), at least one separating wall (401), and at least one neck (407). The wall extends from the back side (96) of a combustor front panel and defines a damping chamber (406). The inlet is defined within the wall and is oriented to channel a flow of air into the damping chamber. The outlet is defined within the back side of the front panel. The separating wall is oriented to separate the damping chamber into a first volume (403) and a second volume (405). The first volume of the damping chamber is configured to damp an acoustic pressure oscillation at a first frequency. The second volume of the damping chamber is configured to damp the acoustic pressure oscillation at a second frequency. The neck extends through the separating wall and is axially offset from the outlet.