Exhaust Stack Fiber Mesh Acoustic Attenuation
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Solution Overview
Problem
Current exhaust stacks in power plants, particularly gas turbine systems, face challenges in effectively attenuating noise due to the limitations of existing silencing methods, which often require costly and complex retrofits to meet regulatory noise standards, and existing solutions like perforated sheets and metal meshes are inefficient in sound absorption.
Innovation Solution
The implementation of an exhaust stack assembly with a fiber mesh internal surface, exposed to the exhaust gas flow, which eliminates the need for protective covers and sound-reflecting structures, allowing for more effective noise attenuation and potentially reducing the stack's height and initial costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If perforated sheets and metal meshes are used to shield acoustic insulation material, then the acoustic insulation material is protected, but sound reflection increases and attenuation effectiveness decreases
Solution Approach 1:
The patent removes the perforated sheet and metal mesh components from the exhaust stack design, exposing the acoustic insulation material directly to the exhaust stream. This extraction eliminates the sound-reflecting barriers that were previously necessary for protection, allowing sound waves to penetrate and be absorbed by the insulation material, thereby improving attenuation effectiveness while maintaining material protection through direct exposure design
Solution Approach 2:
The patent utilizes porous acoustic insulation material that can withstand direct exposure to the exhaust stream. The porous structure allows the material to absorb sound waves effectively while resisting the harsh environmental conditions, eliminating the need for protective perforated sheets and metal meshes that would otherwise reflect sound and reduce attenuation performance
2Object-generated harmful factors
If additional silencers or increased silencing length are added, then acoustic attenuation is improved, but device complexity and cost increase
Solution Approach 1:
The patent changes the operational parameters of the acoustic insulation material by exposing it directly to the exhaust stream without protective barriers. This parameter change allows the material to function more effectively in the harsh environment, achieving superior acoustic attenuation with a single-stage design rather than requiring multiple silencers or extended silencing lengths, thereby reducing system complexity and cost
3Reliability
If perforated sheets and metal meshes are used, then acoustic insulation material is contained, but manufacturing complexity and cost increase
Solution Approach 1:
The patent extracts and removes the perforated sheet and metal mesh components from the manufacturing process. By eliminating these intermediate protective layers, the design simplifies manufacturing operations, reduces material requirements, and lowers overall system cost while maintaining effective containment and protection of the acoustic insulation material through direct exposure design
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 solution provides enhanced acoustic attenuation per linear foot of exhaust stack, reduces the need for additional silencers, lowers airside pressure drop, and simplifies maintenance, while maintaining structural integrity and durability in high-temperature environments.
Implementation Method 1
Each of the plurality of attenuation modules includes a fiber mesh. The fiber mesh is exposed to the exhaust gas in the interior.
Data Source
AI summary
An exhaust stack assembly includes an exhaust stack having an internal surface that defines an interior of the exhaust stack. The exhaust stack is configured to receive exhaust gas from at least one turbomachine component and exhaust the exhaust gas to atmosphere. The exhaust gas assembly further includes a plurality of attenuation assemblies disposed in the interior, each of the plurality of attenuation assemblies including a base substrate generally oriented in the direction of flow of the exhaust gas through the interior, each of the plurality of attenuation assemblies further including a plurality of attenuation modules mounted to the base substrate. Each of the plurality of attenuation modules includes a fiber mesh. The fiber mesh is exposed to the exhaust gas in the interior.