Gas Turbine Burner Lance Spacer for Nozzle Alignment
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Solution Overview
Problem
In gas turbine burners, the alignment of coaxial nozzles in the lance is often disrupted due to thermal loads and differential thermal expansion, leading to incorrect fuel and air injection, which affects fuel penetration into hot gases.
Innovation Solution
A lance design with a spacer or collar fixed to both the inner and outer ducts, preventing relative movement and maintaining the pre-defined coaxial alignment of nozzles, ensuring stable nozzle axis positioning despite thermal deformations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the outer duct is provided with a flange that slidingly rests on the inner duct to connect the ducts, then the device complexity is reduced and ease of manufacture is improved, but the manufacturing precision and reliability of nozzle alignment deteriorate due to deformation under thermal loads and forces
Solution Approach 1:
The lance is divided into separate ducts (inner and outer) that are connected through a spacer, allowing each component to be manufactured independently and then assembled. This segmentation enables the use of a flange connection for ease of manufacture while the spacer compensates for alignment issues through adjustment mechanisms.
Solution Approach 2:
The connection between ducts is made adjustable rather than fixed. The spacer allows for dynamic adjustment of the relative positions of the ducts, enabling compensation for thermal deformation and manufacturing tolerances. This dynamic adjustment mechanism maintains nozzle alignment precision despite the simplified flange connection.
2Adaptability or versatility
If different materials with different thermal expansion coefficients are used in the ducts, then the adaptability and resistance to thermal stress are improved, but the manufacturing precision of nozzle alignment deteriorates due to differential thermal expansion
Solution Approach 1:
The spacer introduces a variable parameter (adjustable distance) that can compensate for differential thermal expansion. By allowing the distance between ducts to change dynamically, the system can accommodate different materials with different thermal expansion coefficients while maintaining nozzle alignment through adjustment.
Solution Approach 2:
The connection system is made dynamic through the adjustable spacer, which can adapt to thermal expansion differences in real-time. This allows the use of different materials for thermal stress resistance while the spacer compensates for the resulting alignment changes through adjustment mechanisms.
3Device complexity
If the flange connection is used to connect inner and outer ducts, then the device complexity is reduced, but the stability of nozzle alignment deteriorates under operational forces and thermal loads
Solution Approach 1:
The lance is segmented into separate ducts connected by a spacer, which isolates the alignment-critical nozzle sections from the forces acting on the ducts. This segmentation allows the use of simple flange connections for low device complexity while the spacer maintains alignment stability by providing a stable reference framework.
Solution Approach 2:
The spacer acts as an intermediary element between the inner and outer ducts. It mediates the connection by providing a stable reference that maintains nozzle alignment while allowing the ducts to experience operational forces independently. This intermediary function preserves alignment stability without requiring complex rigid connections.
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 maintains the correct alignment of inner and outer nozzles, preventing axis shifting and ensuring proper fuel and air injection, even under thermal stress, thereby improving combustion efficiency.
Implementation Method 1
These thermal loads cause deformations, which may be amplified in case different materials, having different thermal expansion coefficients, are used.
Data Source
Figure 1~3
Figure 4~6
AI summary
The lance (2) of a gas turbine burner comprises an inner duct (10) with inner nozzles (11) and an annular outer duct (12) encircling the inner duct (10) and provided with outer nozzles (13). Between a terminal portion of the inner duct (10) and a terminal portion of the outer duct (12) a spacer (15) is provided. The spacer is fixed to both the inner duct (10) and outer duct (12).