Gas Turbine Combustor Pipe Deformation for Thermal Stress Relief
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Solution Overview
Problem
Gas turbine combustors face stress concentration due to heat expansion, leading to reduced lifetime and increased machining costs, particularly in complex structures with thin portions for fuel passage formation.
Innovation Solution
A combustor design featuring a flange portion, an annular extension portion, and a pipe portion that connects the flange to the extension, allowing for flexible deformation and reducing stress at connection points due to differing heat expansion rates, thereby simplifying the configuration and reducing machining costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a thin portion is created in the ring member to reduce stiffness and allow deformation during heat expansion, then stress concentration at welding parts is reduced, but the structure becomes complicated and machining cost increases
Solution Approach 1:
The invention applies local quality by creating a thin portion only at specific locations (radially outer side of the ring member) rather than throughout the entire structure. This localized thinning reduces stiffness only where needed for stress relief, while maintaining structural integrity elsewhere, thus resolving the contradiction between stress reduction and structural simplicity
Solution Approach 2:
The invention changes the physical parameter of the ring member by varying its thickness (creating a thin portion with smaller radial width) at specific locations. This parameter change allows the structure to deform more easily during thermal expansion, reducing stress concentration without requiring complex overall structural changes
2Duration of action of stationary object
If a thin portion is created in the ring member to allow deformation during heat expansion, then the lifetime of the combustor is extended, but the machining cost of the thin portion increases
Solution Approach 1:
By localizing the thin portion to the radially outer side of the ring member rather than processing the entire ring, the machining scope is minimized. This localized approach extends combustor lifetime through stress reduction while controlling machining costs by limiting the area requiring special processing
Solution Approach 2:
The invention applies partial action by creating a thin portion only at the radially outer side where stress concentration occurs during thermal expansion, rather than thinning the entire ring member. This partial processing achieves the lifetime extension goal while minimizing machining costs
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 design effectively mitigates stress concentration from heat expansion, extends the combustor's lifetime, and reduces machining costs by allowing the pipe portion to deform easily at connection points, maintaining a simple configuration.
Implementation Method 1
the temperature of a combustor of a gas turbine increases during operation of the gas turbine, which may cause heat expansion of constituent members of the combustor
Data Source
AI summary
A combustor for a gas turbine includes: a flange portion to be mounted to a casing; an extension portion having an annular shape and extending from the flange portion along an axial direction of the combustor; a pipe portion having a first end connected to the flange portion and a second end connected to an outer peripheral surface of the extension portion, the pipe portion extending from the first end to the second end at an outer side of the extension portion in a radial direction; and at least one fuel nozzle configured to receive supply of a fuel via the pipe portion and a passage disposed inside the extension portion.