Acoustic Damper Combustor Liner Throat Design
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Solution Overview
Problem
Thermo-acoustic oscillations in gas turbine combustors result in high noise levels and mechanical distress due to the combustion of fuel-air mixtures and dilution air, which existing technologies have not effectively addressed.
Innovation Solution
The integration of Helmholtz resonating dampers within the combustor liners, specifically in the converging-diverging sections of the outer and inner liners, which form acoustic dampers to mitigate these oscillations by using bridge members and dilution openings to create cavities that dampen acoustic waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If combustion of fuel-air mixture and dilution air mixing occurs in the combustor, then energy generation and cooling function are achieved, but thermo-acoustic oscillations produce high noise levels and mechanical distress
Solution Approach 1:
The patent introduces acoustic dampers as intermediary elements within the combustor liner structure. These dampers act as mediators that absorb and dissipate acoustic energy from thermo-acoustic oscillations without interfering with the combustion process or dilution air mixing function, thereby reducing noise levels and mechanical distress while maintaining power generation
Solution Approach 2:
The patent converts the harmful acoustic energy from thermo-acoustic oscillations into beneficial effects by using acoustic dampers that absorb this energy and convert it into heat through viscous dissipation. The oscillatory flow within the damper cavities creates friction that dissipates acoustic energy, transforming the harmful oscillations into a benign thermal effect while protecting the combustor from mechanical distress
2Object-affected harmful factors
If acoustic dampers are integrated into combustor liners, then thermo-acoustic oscillations are reduced, but device complexity increases
Solution Approach 1:
The patent merges the acoustic damper functionality with the existing combustor liner structure. The dampers are integrated into the liner's wall thickness or as protrusions from the liner surface, combining the structural support function of the liner with the acoustic damping function in a single unified component, thereby reducing overall device complexity despite adding acoustic control capability
Solution Approach 2:
The combustor liner is designed to serve multiple functions simultaneously: structural support, thermal insulation, and acoustic damping. The liner material and structure are selected to provide both mechanical strength and acoustic absorption properties, allowing a single component to fulfill multiple roles and reducing the need for separate acoustic treatment elements
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 effectively reduces thermo-acoustic oscillations, leading to lower noise levels and reduced mechanical stress within the turbine engine, enhancing operational stability and efficiency.
Implementation Method 1
The integration of Helmholtz resonating dampers within the combustor liners, specifically in the converging-diverging sections of the outer and inner liners, which form acoustic dampers to mitigate these oscillations by using bridge members and dilution openings to create cavities that dampen acoustic waves
Data Source
AI summary
A combustor liner has an outer liner and an inner liner that define a combustion chamber therebetween, the combustion chamber having a dilution zone. The outer liner and the inner liner each have a converging-diverging section extending into the dilution zone of the combustion chamber and form a throat between them. A bridge member extends across the converging-diverging sections to form a damper cavity therebetween. Each of the converging-diverging sections includes at least one dilution opening defined through the respective converging-diverging section at the throat, and includes a damper inlet feed member on a downstream portion of the converging-diverging section, so that an acoustic damper is defined by the converting-diverging section, the bridge, and the damper inlet feed. The acoustic damper dampens acoustic characteristics of the combustor.