Spiral Scroll Combustor for Compact Gas Turbine Packaging
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Solution Overview
Problem
Small gas turbine engines face challenges with radial and axial protrusions due to traditional combustor designs, leading to manufacturing issues, efficiency problems, and increased maintenance costs, particularly with fuel injectors that are prone to plugging and clogging.
Innovation Solution
A gas turbine engine with a combustor assembly featuring a volute walled enclosure defining a spiral scroll pitch axis, which decreases cross-sectional area along the downstream direction to maintain constant axial velocity and minimize non-axisymmetric features, incorporating a single fuel injector and outer casing for improved packaging and reduced protrusions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single can combustor with a single fuel injector is used in small gas turbine engines, then manufacturing tolerances and plugging issues are improved, but radial and axial dimensions of the engine increase
Solution Approach 1:
The combustor is nested within the turbine first stage annulus, utilizing the space between the turbine rotor and casing. This allows the combustor to be positioned within the existing engine envelope without requiring additional radial or axial protrusions, thereby maintaining compact dimensions while using a reliable single fuel injector design
Solution Approach 2:
The combustor employs a spiral scroll configuration that wraps around the turbine axis, utilizing the circumferential dimension to accommodate the combustion chamber volume. This spiral arrangement allows the combustor to fit within the limited radial space by distributing its volume along the circumferential direction rather than requiring additional radial protrusion
2Productivity
If traditional combustor designs with radial and axial protrusions are used, then packaging efficiency is worsened, but manufacturing simplicity is improved
Solution Approach 1:
The combustor employs an asymmetric spiral scroll geometry that is optimized to fit within the specific constraints of the turbine annulus. The scroll cross-sectional area varies along its length, being larger at the inlet and smaller at the outlet, creating an asymmetric shape that efficiently packages the combustion chamber within the available space while maintaining manufacturing feasibility
Solution Approach 2:
The combustor utilizes a curved spiral scroll configuration rather than straight or angular geometries. This curved design allows the combustor to smoothly follow the circular path around the turbine axis, efficiently utilizing the annular space and improving packaging by eliminating dead zones and optimizing fluid flow paths
3Quantity of substance
If multiple fuel injectors are used to maintain compact size, then engine cost is reduced, but manufacturing tolerances and maintenance costs worsen
Solution Approach 1:
The single fuel injector is designed with multiple fuel passages and distribution channels that serve the entire combustor volume. This multi-functional injector replaces multiple separate injectors, providing both fuel delivery and flow distribution functions in a single component with robust, manufacturable dimensions and tolerances
Solution Approach 2:
Multiple fuel injection functions are merged into a single fuel injector assembly. The injector includes an internal fuel distribution system with multiple passages that deliver fuel to different regions of the combustor, combining what would traditionally require multiple separate injector components into one robust unit
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 design enhances radial and axial packaging in small gas turbine engines, reducing part quantities and complexities, while maintaining efficient combustion and reducing maintenance costs by minimizing plugging and clogging issues.
Implementation Method 1
a cross sectional area of the combustion chamber defined by the walled enclosure decreases along a downstream direction to provide an approximately constant axial velocity downstream flow of combustion gases through the combustion chamber along the pitch axis
Implementation Method 2
Gas turbine engine comprising a combustor assembly
Data Source
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AI summary
The present disclosure is directed to a combustor assembly 50 for a gas turbine engine 10. The combustor assembly 50 comprises a volute walled enclosure 110 defining a spiral scroll pitch axis 11 disposed at least partially circumferentially around a centerline axis 12 of the gas turbine engine 10, in which the walled enclosure 110 is defined around the pitch axis 11, and the walled enclosure 110 defines a combustion chamber 62 therewithin.