Flame Holder Thermal Expansion Design for Gas Turbine Burners
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Solution Overview
Problem
High temperature gradients in flame tether configurations lead to increased stress concentrations in flame holders, reducing their service life in burners and gas turbines.
Innovation Solution
Incorporating elongate depressions with undercuts in the flame holder's flame connection area to provide thermal expansion spaces, allowing for unhindered material expansion and reducing mechanical stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flame holder surface is heated to high temperature to sustain combustion reactions, then flame stability is improved, but thermal stress concentrations increase beyond acceptable limits
Solution Approach 1:
The patent applies thermal expansion principle by designing the flame holder with elongate depressions that provide expansion space for the heated material. The flame connection area is allowed to expand freely into these depressions when heated to high temperatures for flame stabilization, preventing stress buildup from constrained expansion. This resolves the contradiction by accommodating the necessary thermal expansion while maintaining structural integrity.
Solution Approach 2:
The patent applies local quality principle by creating localized depressions specifically in the flame connection area where high temperatures occur. This allows the heated region to have different structural characteristics (expansion space) compared to the cooler regions, enabling localized thermal management. The flame connection area can expand into the depressions without affecting the overall structural strength of the cooler portions.
2Strength
If the flame connection area is constrained by the cooler portions of the flame holder, then structural integrity is maintained, but thermal expansion is restricted causing stress concentrations
Solution Approach 1:
The patent applies segmentation principle by dividing the flame holder into functionally distinct regions: the flame connection area with depressions that allows expansion, and the cooler structural portions that maintain integrity. The depressions create a segmented structure where the heated zone is isolated from the cooler zones, allowing differential movement without transmitting stress to the entire structure.
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 mitigates mechanical stress concentrations, thereby increasing the service life of the flame holder and burner by accommodating thermal expansion without restricting material expansion.
Implementation Method 1
the depression provides a thermal expansion space for material of the flame holder located in the flame connection area
Data Source
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AI summary
The invention relates to a burner (1) of a gas turbine having a flame holder (30; 30') axially adjoining a combustion chamber (20) for stabilizing a flame. In order to achieve an increased service life of the burner, the flame holder (30; 30') has at least one elongated depression (30a; 30a') in or adjacent to a flame attachment region (31; 31') subjected to the flame, which depression provides a thermal expansion space for material of the flame holder (30; 30') that is located in the flame attachment region, so that material stresses are reduced.