Spherical Sealing Element Combustor Assembly
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Solution Overview
Problem
In gas turbine engines, the relative movement between the combustor liner and fuel spray nozzles due to thermal expansion leads to inefficiencies in combustion, as the burner seal is exposed to hot gases, causing fluid flow separation and increased residence time, which reduces combustion efficiency and increases undesirable exhaust emissions.
Innovation Solution
A combustor assembly with a sealing element featuring spherical bearing surfaces and an annular clearance mechanism, allowing relative movement between the combustor wall and the sealing element, while an air passageway within the sealing element delivers cooling air to maintain a stable fluid flow and prevent separation, ensuring consistent fuel-air ratios and residence times.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If planar geometry is used for the burner seal and combustor liner, then manufacturing is simplified, but fluid flow separation occurs and combustion efficiency is reduced
Solution Approach 1:
The burner seal is designed with a spherical geometry that conforms to the conical flow profile of the fuel-air mixture. The spherical surface allows the fluid flow to remain attached as it moves along the combustor liner, preventing separation and recirculation. This curved geometry resolves the contradiction by maintaining combustion efficiency through proper flow attachment while still being manufacturable using standard spherical machining processes.
2Reliability
If the burner seal is exposed to hot combustion gases, then the sealing function is maintained, but the seal requires cooling and residence time varies
Solution Approach 1:
The spherical geometry of the burner seal creates a smooth, continuous surface that guides the conical fluid flow without causing separation. This ensures that gases maintain a consistent residence time as they flow along the spherical surface into the combustion chamber, eliminating the time variation problem while the seal remains exposed to hot gases for its sealing function.
3Temperature
If cooling air is directed through the burner seal, then the seal is cooled, but fluid flow separation is caused
Solution Approach 1:
The spherical geometry of the burner seal allows cooling air to be directed through the seal structure without disrupting the main fluid flow. The curved surface guides the fuel-air mixture smoothly, preventing separation even when cooling air is introduced. This resolves the contradiction by maintaining both seal cooling and combustion efficiency through the advantageous spherical configuration.
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 enhances combustion efficiency by maintaining a stable fluid flow and reducing emissions by controlling the relative movement and cooling the sealing element, thereby optimizing fuel-air ratios and residence times within the combustion chamber.
Implementation Method 1
an air passageway within the sealing element delivers cooling air to maintain a stable fluid flow and prevent separation
Implementation Method 2
the first bearing surface is concave and forms part of a first spherical surface such that the first bearing surface and the second bearing surface are configured to move relative to each other about a central point of the first spherical surface
Implementation Method 3
Fuel is combined with high pressure air and combusted, and the resulting high temperature gases are exhausted to drive the turbine
Data Source
AI summary
A combustor assembly for gas turbine engine, combustor assembly including: combustor wall including interior surface and combustor wall opening, wherein interior surface partially defines combustion chamber, wherein combustor wall opening extends between combustion chamber and its exterior; sealing element disposed partially within combustor wall opening and includes air inlet, air outlet and air passageway, wherein air outlet exits into combustion chamber and delivers flow of air received from exterior of combustion chamber via air inlet and air passageway to combustion chamber; and fuel nozzle coupled to sealing element and configured to deliver fuel into combustion chamber, wherein combustor wall further includes first bearing surface and sealing element further includes second bearing surface, wherein first bearing surface is concave and forms part of first spherical surface such that first and second bearing surfaces are configured to move relative to each other about central point of first spherical surface.