Removable Torch Igniter Head for Gas Turbine Pressure Sealing
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Solution Overview
Problem
Torch igniters in gas turbine engines face high operating temperatures and pressure differentials, leading to potential damage and maintenance challenges, particularly affecting temperature-sensitive electrical connections and requiring thick housings to withstand pressure-induced deformation.
Innovation Solution
A removable igniter head design with internal mounting within the high-pressure case, utilizing a sealing flange to prevent air leakage and allowing for thinner housings, along with cooling channels and removable components to facilitate maintenance, and using additive manufacturing for robust construction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of repair
If the igniter head is made removable for ease of maintenance, then maintenance time and complexity are reduced, but sealing integrity and pressure containment become more difficult to maintain
Solution Approach 1:
The igniter is divided into two main segments: a removable igniter head and a fixed igniter body. The igniter head contains the ignition source and fuel injector, while the igniter body houses the combustion chamber and electrical connections. This segmentation allows the igniter head to be removed and replaced without disturbing the sealed igniter body, thus maintaining sealing integrity while enabling easy maintenance.
Solution Approach 2:
A sealing flange acts as an intermediary component between the removable igniter head and the fixed igniter body. This flange provides a sealed interface that maintains pressure containment while allowing the igniter head to be detached for maintenance. The sealing flange transfers the sealing function from the entire igniter assembly to a specific intermediate component.
2Strength
If thick housings are used to withstand pressure differentials, then structural strength is improved, but device weight and material consumption increase
Solution Approach 1:
The igniter is segmented into a thick-walled igniter body that withstands high pressure differentials and a thinner-walled igniter head that does not require the same pressure resistance. By concentrating the pressure-resistant structure only where needed (in the igniter body containing the combustion chamber), the overall weight is reduced while maintaining structural strength where critical.
Solution Approach 2:
Different wall thicknesses are applied to different parts of the igniter based on local pressure requirements. The igniter body has thick walls to withstand pressure differentials, while the igniter head has thinner walls since it operates at lower pressures. This local differentiation of structural properties optimizes the weight-to-strength ratio.
3Reliability
If electrical connections are exposed to high-temperature combustion zones, then ignition functionality is improved, but temperature-sensitive electrical components suffer damage
Solution Approach 1:
The electrical connections are extracted from the high-temperature combustion zone by placing them in the igniter body, which is positioned outside or at the boundary of the high-pressure case. The ignition source (such as a glow plug or spark generator) extends into the combustion chamber to provide ignition functionality, while the electrical connections remain in the cooler igniter body, protecting them from thermal damage.
Solution Approach 2:
The igniter body serves as an intermediary thermal zone between the high-temperature combustion chamber and the ambient environment. Electrical connections are placed in this intermediate zone, which experiences elevated temperatures but not the extreme temperatures of the combustion gases. This intermediary positioning protects electrical components while maintaining ignition functionality.
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 continuous operation with reduced weight and maintenance downtime by protecting electrical connections from high temperatures and simplifying component replacement, while maintaining efficient combustion and sealing integrity.
Implementation Method 1
cooling channels and removable components to facilitate maintenance
Implementation Method 2
utilizing a sealing flange to prevent air leakage
Implementation Method 3
an ignition source extending at least partially into the combustion chamber and a fuel injector configured to inject fuel into the combustion chamber
Data Source
Figure 1
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Figure 3
AI summary
A torch igniter for a combustor of a gas turbine engine includes an igniter body (20) and an igniter head. The igniter body is disposed within a high-pressure case (18) of a gas turbine engine and extends primarily along a first axis, and includes an annular wall and an outlet wall. The annular wall surrounds the first axis and defines a radial extent of a combustion chamber therewithin. The outlet wall is disposed at a downstream end of the annular wall, defines a downstream extent of the combustion chamber, and includes an outlet fluidly communicating between the combustion chamber and an interior of the combustor. The igniter head (22) is removably attached to the igniter body at an upstream end of the annular wall, wherein the igniter head defines an upstream extent of the combustion chamber, and includes an ignition source and a fuel injector (34).