Annular Combustor Fuel Manifold Nesting for Thermal Growth
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Solution Overview
Problem
Internal manifold mounting arrangements in gas turbine engines face challenges with incomplete heat-shielding, potential fuel leakage, and axial displacement due to thermal growth, affecting combustion characteristics.
Innovation Solution
An annular combustor design with an inner and outer liner forming an annular combustor chamber, where the fuel manifold and nozzles are positioned entirely inside the combustion chamber, utilizing radially and tangentially oriented nozzle air inlets to enhance fuel-air mixing and reduce thermal growth issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If heat shielding is provided to prevent fuel coking inside the manifold, then fuel coking is prevented, but the device complexity increases and complete heat-shielding is hard to achieve
Solution Approach 1:
The fuel manifold is extracted from the external mounting arrangement and repositioned entirely inside the combustion chamber. This eliminates the need for complex external heat-shielding structures and radial pins, as the manifold is now surrounded by the combustion chamber environment which inherently provides thermal management.
Solution Approach 2:
The fuel manifold is nested within the combustion chamber, with the manifold positioned inside the chamber formed between the inner and outer liners. This nested arrangement allows the combustion chamber to serve as the heat-shielding environment, eliminating separate heat-shielding components.
2Device complexity
If the manifold is not fully enclosed, then device complexity is reduced, but fuel leakage risk increases in case of sealing failure
Solution Approach 1:
The fuel manifold is completely enclosed within the combustion chamber formed by the inner and outer liners. This nested configuration provides a fully enclosed environment that contains any potential fuel leakage within the combustion chamber, eliminating the risk of external fuel leakage while maintaining structural simplicity.
3Ease of operation
If radial pins are used to locate the manifold, then positioning is achieved, but axial displacement occurs due to relative thermal growth affecting combustion characteristics
Solution Approach 1:
The fuel manifold is nested within the combustion chamber with circumferential distribution of fuel nozzles matching the combustor geometry. This nested arrangement accommodates thermal growth through the common combustion chamber environment, eliminating axial displacement issues that would affect combustion characteristics.
Solution Approach 2:
The fuel nozzles are circumferentially distributed on the fuel manifold at specific locations to optimize fuel injection into the combustion chamber. This local optimization of nozzle positioning ensures stable combustion characteristics while accommodating thermal growth of the nested manifold structure.
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 provides complete heat-shielding, prevents fuel leakage, maintains stable combustion characteristics by minimizing axial displacement, and enhances fuel-air mixing, leading to improved combustion efficiency and reduced emissions.
Implementation Method 1
Heat shielding may be required to prevent fuel coking inside the manifold. This design provides complete heat-shielding
Implementation Method 2
relative thermal growth of manifold and combustor leads to axial displacement between the fuel nozzle tip and combustor primary zone which may affect combustion characteristics
Data Source
AI summary
A gas turbine engine comprises a combustor. The combustor comprises an annular combustor chamber formed between an inner liner and an outer liner spaced apart from the inner liner. An annular fuel manifold has fuel nozzles distributed circumferentially on the fuel manifold, the fuel manifold and fuel nozzles positioned entirely inside the combustion chamber.