Torch Ignitor Elbow Reduces Axial Length for Gas Turbine Maintenance
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Solution Overview
Problem
Torch ignitors in gas turbine engines have a high axial length, making routine maintenance and component replacement challenging due to their position within the high-pressure engine case, necessitating a design with reduced axial length for easier line replacement.
Innovation Solution
A torch ignitor system with a combustion chamber oriented about a torch axis, featuring a cap for receiving a fuel injector and glow plug, an elbow for diverting combustion products along an off-axis ignition jet flame, and a tip for independent flame injection into the main combustor, allowing for flexible placement and reduced axial length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional torch ignitor design is used, then reliable ignition and flame stabilization are achieved, but the axial length becomes excessive making maintenance difficult
Solution Approach 1:
The patent reorients the combustion chamber from an axial alignment to a circumferential alignment relative to the engine axis. This dimensional change allows the combustion chamber to extend in the circumferential direction rather than axially, reducing the axial footprint while maintaining the necessary combustion volume and flame stabilization characteristics.
Solution Approach 2:
The torch ignitor is divided into separable components including the combustion chamber assembly, fuel injector, and glow plug. This segmentation allows individual components to be replaced independently through line replacement procedures, improving maintenance accessibility without compromising the integrated functionality required for reliable ignition.
2Ease of repair
If the torch ignitor components are made accessible for maintenance, then ease of repair improves, but the structural integrity and alignment may be compromised
Solution Approach 1:
The torch ignitor system is segmented into modular components (combustion chamber, fuel injector, glow plug) that can be independently accessed and replaced. Each component maintains its precise alignment through dedicated mounting interfaces and positioning features, ensuring that segmentation for maintainability does not compromise structural integrity.
Solution Approach 2:
Alignment features and mounting interfaces are pre-configured during manufacturing to ensure precise positioning of components. This preliminary action establishes the correct geometric relationships between parts before assembly, allowing maintenance personnel to replace components without requiring complex realignment procedures, thus preserving both accessibility and alignment stability.
3Length of moving object
If the combustion chamber is oriented circumferentially, then axial length is reduced for easier maintenance, but the flow path configuration becomes more complex
Solution Approach 1:
The combustion chamber is reoriented from axial to circumferential alignment, changing the primary dimension of extension. This allows the flow path to be configured in the circumferential direction, reducing axial length while accommodating the necessary fuel injection, mixing, and combustion processes through carefully designed internal geometry and component placement.
Solution Approach 2:
The flow path configuration is optimized locally within different zones of the combustion chamber. The fuel injector, glow plug, and combustion chamber geometry are specifically designed to create appropriate flow patterns, mixing zones, and flame stabilization regions adapted to the circumferential orientation, managing complexity through localized optimization rather than uniform design.
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
Enables stable and efficient ignition, relight, and emissions control, while facilitating easier maintenance by reducing the axial length of torch ignitor components within the high-pressure engine case.
Implementation Method 1
at least one glow plug. The torch ignitor includes an elbow connected to the downstream end of the combustion chamber
Implementation Method 2
a combustion chamber oriented about a torch axis, the combustion chamber having axially upstream and downstream ends defining a flow direction through the combustion chamber
Implementation Method 3
an elbow connected to the downstream end of the combustion chamber for diverting combustion products along an ignition jet flame axis that is off of the torch axis
Data Source
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AI summary
A torch ignitor system for a combustor of a gas turbine engine includes a torch ignitor (10), the torch ignitor (10) including a combustion chamber oriented about a torch axis, the combustion chamber having axially upstream and downstream ends (102, 104) defining a flow direction through the combustion chamber, along the axis. The torch ignitor (10) includes a cap (34) defining the axially upstream end of the combustion chamber and oriented about the axis, wherein the cap (34) is configured to receive a fuel injector (45) and at least one glow plug. The torch ignitor (10) includes an elbow (108) connected to the downstream end of the combustion chamber for diverting combustion products along an ignition jet flame axis that is off of the torch axis for injection of combustion products into a gas turbine engine combustor. The torch ignitor (10) further includes a tip (106) at a downstream end of the elbow for issuing the injection of combustion products.