Gas Turbine Combustor Acoustic Cover Layout for Lower-Cost Damping
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Solution Overview
Problem
The existing combustor designs in gas turbines require a pressure-resistant structure for the acoustic cover due to pressure differences between the acoustic space and the atmosphere, leading to increased manufacturing costs.
Innovation Solution
The acoustic cover of the base-end-side acoustic damper is positioned within the gas turbine casing on the outer peripheral side of the outer tube, eliminating the need for a pressure-resistant structure and reducing manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the acoustic cover is disposed outside the gas turbine casing to form the acoustic space, then the acoustic damper can suppress combustion vibration, but the pressure difference between inside and outside the acoustic cover becomes large requiring a pressure resistant structure which increases manufacturing cost
Solution Approach 1:
The patent introduces the gas turbine casing as an intermediary structure that contains the acoustic space. By positioning the acoustic cover inside the gas turbine casing rather than outside, the casing acts as a mediator that equalizes the pressure environment, eliminating the need for pressure-resistant structures on the acoustic cover and thereby reducing manufacturing cost while maintaining vibration suppression functionality.
Solution Approach 2:
The patent creates an equipotential pressure environment by placing the acoustic space within the gas turbine casing. This ensures that the pressure inside the acoustic cover is the same as the pressure inside the gas turbine casing, eliminating the pressure difference that would otherwise require special pressure-resistant construction and reduce manufacturing complexity and cost.
2Reliability
If the acoustic space communicates with the gas turbine casing through acoustic holes, then the acoustic damper can function, but the pressure in the acoustic space becomes higher than atmospheric pressure requiring the acoustic cover to be pressure resistant
Solution Approach 1:
The gas turbine casing serves as an intermediary that mediates the pressure relationship. By containing the acoustic space within the casing, it ensures that the acoustic cover experiences the same pressure as the rest of the casing interior, eliminating the need for pressure-resistant construction while allowing the acoustic holes to maintain damper functionality.
3Ease of manufacture
If the acoustic cover is positioned on the outer peripheral side of the outer tube within the gas turbine casing, then the pressure difference is eliminated reducing manufacturing cost, but the air flow may be affected
Solution Approach 1:
The patent applies local quality by positioning the acoustic cover specifically on the outer peripheral side of the outer tube rather than in other locations within the casing. This localized positioning minimizes interference with the main air flow path through the inner tube while still achieving the pressure equalization benefit, thus balancing manufacturing cost reduction with air flow efficiency.
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 configuration suppresses manufacturing costs while effectively damping combustion vibrations and preventing incomplete fuel combustion by optimizing air flow within the combustor.
Implementation Method 1
an acoustic cover 63 that forms a base-end-side space 67 in the gas turbine casing 15 on an outer peripheral side of the outer tube 43 in cooperation with the outer tube forming part 61
Implementation Method 2
The outer tube forming part 61 is provided with a plurality of acoustic holes 62 penetrating the base-end-side space 67 from the inner peripheral side of the outer tube 43
Implementation Method 3
a transition piece 45 that forms a tubular shape around the axis Ac, is connected to the inner tube 44, and allows the fuel injected from the in-tube injection nozzle 47 to be combusted on an inner peripheral side of the transition piece 45
Implementation Method 4
a compressor 20 that compresses air to generate compressed air
Data Source
AI summary
This combustor is provided with an outer cylinder, an inner cylinder, a direct injection nozzle, a tail pipe, and a base end side acoustic attenuator. The outer cylinder is disposed inside a gas turbine casing. The inner cylinder is disposed on the inner circumferential side of the outer cylinder. The direct injection nozzle is disposed on the inner circumferential side of the inner cylinder. The tail pipe is connected to the inner cylinder, and fuel injected from the direct injection nozzle is burned on the inner circumferential side of the tail pipe. The base end side acoustic attenuator has an outer cylinder formation portion that is a part of a plate forming the outer cylinder, and an acoustic cover forming a base end side space in the gas turbine casing on the outer circumferential side of the outer cylinder in cooperation with the outer cylinder formation portion.