Gas Turbine Burner Assembly Cooling Air Distribution
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Solution Overview
Problem
Gas turbine burners face premature component failure due to high local stresses caused by temperature gradients and peeling of ceramic coatings, which limits their useful life.
Innovation Solution
The burner assembly incorporates multiple mixing ducts with axial mixing tubes and annular end plates featuring radial bores for cooling air introduction, reducing temperature-induced stresses through cooling air pockets and elongated depressions for thermal expansion relief, and resonator openings for stress reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If turbine inlet temperatures are increased to achieve increased output and greater efficiency, then power and efficiency are improved, but temperature-induced stresses increase causing premature component failure
Solution Approach 1:
Cooling air is introduced as an intermediary substance between the hot combustion gases and the end plate. The cooling air flows through axial bores in the end plate to create a thermal barrier, reducing direct thermal exposure and preventing ceramic coating failure while allowing high turbine inlet temperatures for improved power output
2Reliability
If cooling air is introduced through axial bores in the end plate, then temperature distribution is improved and component life is extended, but device complexity increases
Solution Approach 1:
Cooling bores are strategically positioned only in regions of highest thermal stress - specifically in the circumferential edge regions of the end plate that face the combustion chamber. This localized approach provides cooling precisely where needed without requiring a complex cooling system throughout the entire component, thus extending component life while limiting complexity increase
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 design extends the useful life of the burner components by reducing temperature-induced stresses and achieving a more homogeneous temperature distribution, making the components more flexible and cost-effective.
Implementation Method 1
cooling air can be transported simply into thermally stressed regions of the burner in order to reduce the temperature there during operation or to ensure a more homogeneous temperature distribution
Implementation Method 2
the at least one opening opens into a chamber or a cooling air pocket which is open toward the annular space. As a consequence of these chambers or cooling air pockets, the accumulation of material in the region close to the combustion chamber is reduced. Moreover, a more homogeneous temperature distribution results
Implementation Method 3
By introducing relieving slits into thermally stressed regions, this component is made more flexible at highly stressed points and can thus react better to thermal expansion without the stress values becoming too high
Data Source
AI summary
A burner assembly with a combustion chamber, a plurality of mixing ducts leading into the combustion chamber, where combustion air and introduced fuel are mixed. The mixing ducts are formed by mixing tubes extending axially through an annular space between a tubular outer wall, a tubular inner wall arranged radially at a distance from the outer wall, a ring-shaped end plate arranged upstream and a ring-shaped end plate arranged downstream. The end plates have through-openings, which accommodate and/or extend the mixing tubes, and the end plates have, both radially inside and outside, a circumferential edge extending in the direction of the annular space, with axial bores in the edge of the ring-shaped end plate arranged downstream. The axial bores extend from the annual space into the end plate, and at least one opening is for removing cooling air, the opening branching from the axial bore.