Self-Adjusting Helmholtz Damper for Gas Turbine Pulsation Damping
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Solution Overview
Problem
Existing solutions for adjusting Helmholtz damper resonance frequency to match changing load conditions in gas turbines are costly and impractical due to space constraints and reliance on movable components or multiple dampers.
Innovation Solution
A self-adjusting Helmholtz damper design that utilizes a movable piston within the damper volume, driven by the pressure drop between the compressor outlet and combustor pressures, to dynamically adjust the damper volume and resonance frequency, minimizing space requirements and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple Helmholtz dampers tuned to different frequencies are used to cover varying load conditions, then damping performance across all load conditions is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent applies the dynamics principle by making the damper volume dynamically adjustable through a movable piston. The piston can shift the partition between the first and second parts of the damper volume, allowing the resonance frequency to be continuously adjusted to match the pulsation frequency under different load conditions. This eliminates the need for multiple fixed-frequency dampers while maintaining optimal damping performance across the full operating range.
2Adaptability or versatility
If a closed loop volume adjustment system with moving pistons is used to maintain maximum damping properties, then damping performance is improved, but manufacturing costs and device complexity increase
Solution Approach 1:
The patent applies the self-service principle by designing a system where the movable piston is automatically positioned by the pressure difference between the first and second parts of the damper volume. The piston moves in response to the prevailing pressure conditions without requiring external actuators, control systems, or power sources. This self-adjusting mechanism maintains optimal damping performance while avoiding the high costs and complexity associated with controlled volume adjustment systems.
3Adaptability or versatility
If the damper volume is made adjustable to maintain resonance frequency tuning under varying load conditions, then damping performance is improved, but device complexity and space requirements increase
Solution Approach 1:
The patent applies the segmentation principle by dividing the total damper volume into a first part and a second part separated by a movable piston. The partition wall with the piston allows independent adjustment of the first part's volume while the second part provides a reservoir that compensates for volume changes. This segmented design enables continuous volume adjustment without requiring the entire damper to be large, thereby maintaining compact dimensions while achieving可调 resonance frequency.
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 continuous damping performance across varying load conditions without increasing costs or complexity, ensuring robust and efficient pulsation damping within the gas turbine combustor.
Implementation Method 1
a piston (27, 44), which is moveable within said damper volume (25, 40) and divides said damper volume into a variable first part (V1) on one side of said piston (27, 44), which variable first part (V1) is connected to said neck tube (26, 43), and a correspondingly variable second part (V2) on the other side of said piston (27, 44), wherein said piston (27, 44) is driven by a pressure drop between said first and second part (V1, V2) of said damper volume (25, 40)
Implementation Method 2
The resonance frequency f of this damper can be approximately calculated by the formula: f = (c/2π) * sqrt(A N /(V*L N )) with the speed of sound c, and the area A N and length L N of neck tube 22
Data Source
Figure 1
Figure 2~3
Figure 4a~5
AI summary
A Helmholtz damper (24), especially for damping pulsations in a combustor of a gas turbine, comprises a damper volume (25, which can be connected to a damped space (19) by means of a neck tube (26), and further comprises a piston (27), which is moveable within said damper volume (25) and divides said damper volume (25) into a variable first part (V1) on one side of said piston (27), which variable first part (V1) is connected to said neck tube (26), and a correspondingly variable second part (V2) on the other side of said piston (27). The control mechanism is substantially simplified in a more compact design by said piston (27) being driven by a pressure drop (Δp) between said first and second part (V1, V2) of said damper volume (25).