Continuous Glow Ignition Head Assembly for Gas Turbine Engines
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Solution Overview
Problem
Conventional spark igniters in gas turbine engines face challenges such as difficulty in igniting fuel in cold conditions, vulnerability to carbon deposits, high voltage issues, and electromagnetic interference, leading to unreliable ignition and reduced engine performance, especially under low power or transient conditions.
Innovation Solution
A head assembly for the ignition system that includes a spider manifold with integral fuel and oxidizer conduits, a coolant conduit, and an insulating body for electrical connections, using low voltage DC electric elements and glow plugs to provide continuous ignition, reducing the risk of contamination and electromagnetic interference, and allowing for stable operation across varying engine conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If intermittent spark ignition is used, then the igniter structure is simpler, but ignition reliability deteriorates in cold conditions and transient operations
Solution Approach 1:
The patent applies continuous ignition instead of intermittent spark ignition. The glow plug maintains continuous glowing heat to ignite the fuel-air mixture, ensuring reliable ignition under cold conditions and transient operations. This continuous thermal action eliminates the timing sensitivity and reliability issues associated with intermittent sparking.
Solution Approach 2:
The patent changes the ignition parameter from high-voltage intermittent sparks to low-voltage continuous glow. By transforming the electrical ignition method to a thermal glow mechanism, the system achieves reliable ignition without the complexities of high-voltage pulse generation and timing control.
2Use of energy by moving object
If high voltage spark igniters are used, then ignition energy is sufficient, but electromagnetic interference increases and circuit reliability decreases
Solution Approach 1:
The patent replaces the high-voltage electrical spark mechanism with a low-voltage glow plug system. The glow plug converts electrical energy directly to thermal energy through resistive heating, eliminating the electromagnetic discharge process that causes interference. This substitution maintains sufficient ignition energy through continuous thermal exposure rather than brief high-voltage sparks.
3Reliability
If fuel is sprayed toward the combustor wall near the igniter, then ignition probability increases, but carbon deposits increase and igniter performance deteriorates
Solution Approach 1:
The continuous glow from the glow plug provides sustained thermal energy to the fuel-air mixture, ensuring ignition without requiring fuel concentration near the igniter surface. This eliminates the need to spray fuel toward the combustor wall, thereby preventing carbon deposit formation on the igniter while maintaining high ignition probability.
4Reliability
If the igniter is operated continuously to prevent flameout, then flameout protection is improved, but igniter deterioration accelerates
Solution Approach 1:
The patent changes the operating parameters of the igniter by using a glow plug that operates at lower temperature and voltage compared to intermittent spark igniters. The continuous low-power glow mode reduces thermal stress and material degradation, extending the service life while maintaining flameout protection capability throughout the engine mission.
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 solution enables improved ignition reliability and extended engine life by maintaining a stable flame, reducing carbon deposits, minimizing electromagnetic interference, and allowing continuous operation without overheating, thus enhancing ignition performance and durability.
Implementation Method 1
using low voltage DC electric elements and glow plugs to provide continuous ignition
Implementation Method 2
a coolant conduit configured and adapted for supplying coolant to a face of the head block
Implementation Method 3
an insulating body for electrical connections
Data Source
Figure 1
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AI summary
A head assembly (160) for an ignition system (100) includes a head block (162) and a plurality of igniters (166) seated in in the head block. The head block (160) has an issue aperture (168) and defines an issue axis (170), and is configured and adapted for sealably coupling with an igniter combustion chamber (156). The igniters (166) are arranged about the issue aperture (168) and include respective ignition members arranged obliquely with respect to the issue axis (170) for igniting fuel exiting the issue aperture irrespective to orientation of the ignition system (100).