Turbomachine Combustion Chamber Element Guide with Air Circulation
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Solution Overview
Problem
In turbomachine combustion chambers, the thermal expansion and vibrations lead to relative displacements between the external wall and elements like spark igniters or starting injectors, causing coke formation in guiding devices, which interferes with guidance and can weaken the device and disrupt ignition.
Innovation Solution
A guiding device with coaxial ring and bush, featuring air circulation means such as through orifices and radial grooves, ensures ventilation and cooling, preventing coke formation and improving sliding and cooling efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a guiding device with ring and bush is used to compensate for relative displacements, then the guidance of the element is improved, but coke formation occurs in the cylindrical passage interfering with guidance
Solution Approach 1:
The harmful air/fuel mixture is extracted from the cylindrical passage by creating an alternative air circulation path through the ring and bush structure. Air is directed through the passage to flow around the element, removing the mixture that would otherwise form coke and interfere with guidance.
Solution Approach 2:
Air acts as an intermediary substance that prevents direct contact between the air/fuel mixture and the guiding surfaces. By introducing air circulation, the harmful mixture is diluted and flushed out, preventing coke formation without compromising the guidance function.
2Object-generated harmful factors
If the cylindrical passage is sealed to prevent air/fuel mixture penetration, then coke formation is reduced, but thermal expansion and vibrations cause relative displacements affecting guidance
Solution Approach 1:
The guiding device is designed with dynamic characteristics that allow it to accommodate thermal expansion and vibrations. The ring and bush structure provides guidance while maintaining flexibility to handle relative displacements between the element and the chamber wall, preventing both coke formation and guidance interference.
3Object-generated harmful factors
If air circulation is introduced to prevent coke formation, then the passage is ventilated, but additional structural complexity is required
Solution Approach 1:
The ring and bush structure serves multiple functions simultaneously: it provides guidance for the element, creates air circulation to prevent coke formation, and accommodates thermal expansion and vibrations. This multi-functionality eliminates the need for separate components, reducing overall structural complexity despite the added air circulation capability.
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 air circulation effectively prevents coke formation, maintains the integrity of the guiding device, and ensures consistent ignition by keeping the air/fuel mixture passage clean and cooled.
Implementation Method 1
the air circulation means formed in the ring and/or in the bush and distributed about their axis so as to establish an air circulation in the cylindrical passage from the outside of the combustion chamber toward the inside
Implementation Method 2
The air circulation means make it possible to ventilate the cylindrical passage by feeding in air from the outside of the chamber toward the inside of the combustion chamber
Data Source
AI summary
Device for guiding an element in an orifice in a wall of a turbomachine combustion chamber, including a ring and a bush, the ring being traversed axially by the element and including an external annular rim guided transversely in an internal annular channel of the bush, the ring and the bush delimiting around the element a cylindrical annular passage opening into the chamber, air circulation being provided in the ring and/or in the bush and distributed about their axis so as to establish an air circulation in the cylindrical passage from the outside of the combustion chamber toward the inside.