Turbine Combustion Chamber Mounting via Nested Rings
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Solution Overview
Problem
Turbine engine combustion chamber mounting challenges arise due to thermal expansion differences between metal components, leading to fatigue and potential breakage, and existing designs struggle to balance flexibility and robustness, with dynamic excitation causing hairpin breakage in outer bands.
Innovation Solution
A sandwich engagement configuration using nested radial holder rings with comb-shaped ends and fastener means to securely hold the combustion chamber while allowing radial movement, ensuring axial retention and cooling stream flow, utilizing standard flanged fastener systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional direct connections by means of flanges are used to mount the combustion chamber, then the chamber is securely held in position, but the hairpins are subjected to numerous fluctuating forces due to thermal expansion differences, leading to fatigue and breakage
Solution Approach 1:
The patent applies nesting by placing the inner holder ring inside the outer holder ring, creating a nested configuration where both rings work together to secure the combustion chamber. This nested structure distributes mechanical loads and thermal expansion forces across multiple components, reducing stress on individual hairpins and preventing breakage while maintaining secure mounting.
2Reliability
If the combustion chamber is rigidly fixed to accommodate thermal expansion, then the chamber is securely held, but the hairpins break due to dynamic excitation by sound
Solution Approach 1:
The patent changes the mechanical parameters of the mounting system by introducing holder rings with comb-shaped structures that have multiple teeth. This configuration allows the system to accommodate dynamic excitations from sound waves by providing multiple contact points that can independently respond to vibrations, reducing the transmission of harmful dynamic forces to the hairpins while maintaining overall mounting stability.
3Reliability
If the holder rings are made robust to withstand thermal expansion forces, then the chamber is securely held, but the cooling stream flow towards the annular nozzle is compromised
Solution Approach 1:
The patent applies local quality by designing the holder rings with comb-shaped structures that have teeth with gaps oriented in specific directions. The gaps between the teeth are strategically positioned to allow cooling stream flow towards the annular nozzle, while the teeth themselves provide the necessary mechanical strength for axial retention. This local differentiation allows different parts of the holder ring to serve different functions: the teeth provide structural support while the gaps facilitate cooling flow.
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 enhances flexibility and axial retention, reduces the risk of hairpin breakage, allows for cost-effective maintenance by replacing individual parts, and optimizes flange shape without compromising cooling stream flow.
Implementation Method 1
each of them presents a radial end in the form of a comb having its teeth leaving between them gaps that are directed towards the inside so as to allow a cooling stream to flow towards said annular nozzle
Implementation Method 2
the chamber having a flexible portion in the form of hairpins that connect together the zone for engagement with the casing (the fastener flange) and the zone of the flame tube. Nevertheless, that flexible hairpin is subjected to numerous forces that fluctuate during an operating cycle because of the thermal expansion differences that exist between the chamber and the casing
Data Source
AI summary
A turbine engine has inner and outer annular covers containing an annular combustion chamber and an annular nozzle. The combustion chamber is held in position inside the outer annular cover between two radial holder rings that are nested at least in part one within the other and that have their radially outer first ends secured to the outer annular cover by fasteners and their radially inner second ends in the form of combs holding in position between them a transverse rim of the annular combustion chamber so as to enable a cooling stream to flow towards the annular nozzle and so as to hold the annular combustion chamber axially while leaving it free to move at least radially.