Compact Spark Plug Mounting Device for Gas Turbine Engines
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Solution Overview
Problem
In gas turbine engines, the limited space for housing spark plug mounting devices between the outer casing and the combustion chamber wall poses a challenge, as existing devices are too tall and cannot accommodate protective measures during laser perforation without damaging the assembly.
Innovation Solution
A compact spark plug mounting device featuring a cylindrical chimney with an inward radial collar, a washer, and a bushing with axially spaced collars, allowing radial movement and sealing, while enabling the installation of protective shields and cooling features like impact holes and radial openings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional chimney and spark plug guide assembly is used, then the mounting device can accommodate relative movements between the casing and the combustion chamber wall, but the radial size (height) of the device becomes too large to fit in limited space
Solution Approach 1:
The spark plug guide is nested inside the chimney assembly, with the guide positioned within the cylindrical chimney structure. This nesting arrangement allows the spark plug guide to move radially within the confined space of the chimney, accommodating relative movements between the casing and combustion chamber wall without increasing the overall radial height of the mounting device.
2Reliability
If protectors are installed around the mounting device to prevent laser beam damage, then the assembly is protected during laser perforation, but the total height of the device increases further
Solution Approach 1:
The compact nested design of the spark plug guide within the chimney creates a smaller overall footprint, allowing protectors to be installed with minimal additional height. The protector can wrap around the cylindrical chimney assembly without requiring excessive axial space, thus protecting the assembly during laser perforation while maintaining space constraints.
3Length of moving object
If the radial size of the mounting device is reduced to fit limited space, then the device can be installed in engines with tight clearances, but it becomes difficult to install protectors and accommodate movement
Solution Approach 1:
The spark plug guide is nested within the chimney, creating a compact radial profile that fits limited space. The nested configuration allows the guide to move radially within the chimney's internal volume, accommodating relative movements between components. This nested design also provides a compact external shape that facilitates the installation of protectors around the assembly without requiring excessive space.
Solution Approach 2:
The spark plug guide is designed to move dynamically within the chimney assembly, allowing it to accommodate relative movements between the casing and combustion chamber wall. The guide can shift radially and axially within the confined space of the chimney, maintaining functionality despite the reduced overall size of the mounting device.
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 reduces the overall height of the mounting device, allowing for effective sealing and movement accommodation, while preventing damage from laser perforations and ensuring efficient cooling of the spark plug, thus suitable for engines with limited space constraints.
Implementation Method 1
under the effect of the pressure difference between the inside and the outside of the combustion chamber, the inner collar of the spark plug guide comes to bear against the collar of the chimney, thereby sealing the device
Implementation Method 2
the shape of its components and the way they are assembled together makes it possible to provide an assembly that presents small size in height, while still allowing cylindrically-shaped protectors to be installed around the chimney so as to avoid damaging it while making multiple perforations by laser in the walls of the chamber
Data Source
AI summary
A device for mounting a spark plug in a combustion chamber of a gas turbine engine includes a chimney including a collar extending radially inwards, a washer fastened on an axial end of the chimney so as to project towards the inside of the chimney, and a bushing forming a spark plug guide and including an inner collar and an outer collar that are axially spaced apart from each other by a cylindrical portion. Each collar extends radially outwards. The bushing is floatingly mounted inside the chimney with its collars axially positioned between the collar of the chimney and the washer. The inner collar comes in operation to bear against the collar of the chimney. The outer collar presents an outside diameter (d1) greater than the inside diameter (d2) of the washer.