Annular Combustor Rear Assembly for Small Turbine Flame Stability
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Solution Overview
Problem
Conventional gas turbine engines scaled for smaller applications face challenges in maintaining sufficient thrust, power, efficiency, and flame stability, while also dealing with manufacturing tolerances and regulatory compliance, particularly in civil aviation where noise and fuel consumption are critical factors.
Innovation Solution
A combustor arrangement with specific dimensions and mounting configurations, including an annular combustor body and rear connected by interference or transition fits, retention pins, and a monolithic structure formed by additive manufacturing, ensures stable operation and efficient energy extraction, accommodating thermal expansion and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the overall size of a gas turbine engine is decreased, then the engine becomes suitable for installation on airframes with space constraints, but thrust level becomes insufficient
Solution Approach 1:
The patent applies parameter changes by optimizing the combustor volume-to-fan-radius ratio and adjusting component dimensional relationships to maintain sufficient thrust in a compact engine configuration. The specific combustor volume range (1.4L to 20L) and its relationship to fan tip radius enables adequate combustion chamber volume for thrust generation while keeping overall engine size reduced for airframe installation.
2Force
If turbojet configuration is used to achieve greater thrust levels in smaller engine, then thrust increases, but noise increases and Specific Fuel Consumption worsens
Solution Approach 1:
The patent changes the engine configuration parameter from turbojet to turbofan architecture, which fundamentally alters the thrust generation mechanism. The turbofan configuration with a fan component provides thrust through both the core engine and the fan-driven bypass flow, achieving acceptable thrust levels while significantly reducing noise compared to turbojet configurations.
3Volume of moving object
If conventional gas turbine components are simply scaled down, then engine size decreases, but manufacturing tolerances become increasingly difficult to maintain
Solution Approach 1:
The patent applies parameter changes by redefining the dimensional relationships and tolerance specifications for small-scale components. Instead of simply scaling down conventional components, the invention establishes appropriate tolerance ranges and dimensional parameters specifically suited for small-engine manufacturing, making quality control economically feasible.
Solution Approach 2:
The patent segments the combustor into multiple components (combustor body, combustor rear, guide vanes) that can be manufactured separately and assembled. This segmentation allows each component to be produced within achievable tolerance ranges and facilitates quality control through modular manufacturing and assembly processes.
4Volume of moving object
If combustor volume is reduced in scaled engines, then engine size decreases, but flame stability and combustion efficiency deteriorate
Solution Approach 1:
The patent applies parameter changes by establishing a specific combustor volume range (1.4L to 20L) and maintaining an appropriate combustor volume-to-fan-radius ratio. This optimized parameter relationship ensures sufficient combustion chamber volume for stable flame formation and combustion efficiency while keeping the overall engine size reduced for practical installation.
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 combustor arrangement provides stable operation across varying altitudes and speeds, supports relight mechanisms, and meets regulatory requirements, enhancing thrust and fuel efficiency in small-scale gas turbine engines.
Implementation Method 1
a radially outer surface of the upstream end of the radially outer wall (85) of the combustor rear (83) contacts the radially inner surface of the radially outer wall (53) of the combustor body (81)
Implementation Method 2
a monolithic structure formed by additive manufacturing, ensures stable operation and efficient energy extraction, accommodating thermal expansion and vibration
Implementation Method 3
Gas turbine engines have been developed to provide power for many different air applications
Data Source
AI summary
A combustor assembly (16) for a gas turbine having an annular combustor body and an annular combustor rear. The combustor body and the combustor rear are connected by: i) fit between a radially outer surface of the radially outer wall of the combustor rear and a radially inner surface of the radially outer wall of the combustor body, ii) fit between a radially inner surface of the radially inner wall of the combustor rear and a radially outer surface of the radially inner wall of the combustor body, and iii) one or more retention pins extending radially through respective apertures in the combustor body and in the combustor rear. The combustor rear tapers towards the engine axis as it extends rearwardly.