Venturi Torch Igniter Layout to Cut Combustor Leakage
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Solution Overview
Problem
Existing ignition systems for combustors in turbomachines are inefficient due to leakage and interference with the working fluid flow, leading to reduced efficiency and increased NOx emissions.
Innovation Solution
An igniter design with a mixing channel having a venturi shape and an ignition source positioned downstream of the venturi throat, allowing for efficient mixing of fuel and air before ignition, which minimizes fluid interference and optimizes the combustion process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the ignition system is located along the side of the combustion chamber, then the ignition system can project the spark into the combustion chamber, but this creates leakage and turbulent flow through the penetration in the liner
Solution Approach 1:
The ignition system is extracted from the side wall penetration location and repositioned to the upstream end of the combustor, eliminating the need for penetrations through the combustion chamber liner. This removes the source of leakage and turbulent flow while maintaining ignition functionality through the ejector tube design.
Solution Approach 2:
An ejector tube serves as an intermediary component that delivers the ignition mixture from the upstream end of the combustor to the combustion zone. The tube acts as a sealed conduit that transfers the ignited mixture without requiring penetrations through the liner, thus maintaining sealing integrity.
2Ease of operation
If the ignition system is located along the side of the combustor, then the spark can be projected into the combustion chamber, but this interferes with the flow of working fluid between the liner and flow sleeve, increasing differential pressure
Solution Approach 1:
The ignition system is extracted from the side wall location and repositioned to the upstream end of the combustor. This eliminates the physical obstruction to the working fluid flow between the liner and flow sleeve, reducing the differential pressure across the combustor and improving overall system efficiency.
Solution Approach 2:
The ignition system is repositioned from a side-wall configuration to an axial configuration at the upstream end. This dimensional change allows the ignition function to be performed without occupying space in the radial flow path between the liner and flow sleeve, eliminating flow interference.
3Ease of operation
If the ignition system is located along the side of the combustor, then the spark can be projected into the combustion chamber, but this reduces the amount of working fluid available to mix with fuel in the nozzles
Solution Approach 1:
The ignition system is extracted from the side wall penetration location and repositioned to the upstream end of the combustor. This removes the obstruction to the working fluid flow, allowing the full quantity of compressed air to reach the nozzles and mix with fuel, thereby maintaining optimal combustion conditions.
Solution Approach 2:
The ignition mixture is prepared and ignited in advance at the upstream end of the combustor, before the main working fluid flow enters the combustion chamber. This preliminary ignition action does not interfere with the subsequent flow of working fluid to the nozzles, ensuring adequate fuel-air mixing.
4Ease of operation
If a penetration is created in the combustor liner for the ignition system, then the ignition system can be positioned to project spark into the combustion chamber, but this creates a potential source of leakage and turbulent flow
Solution Approach 1:
The ignition system is extracted from the side wall penetration location and repositioned to the upstream end of the combustor. This eliminates the need for penetrations through the combustion chamber liner, removing the source of leakage and turbulent flow while maintaining ignition functionality through the ejector tube design.
Solution Approach 2:
An ejector tube serves as an intermediary component that delivers the ignition mixture from the upstream end of the combustor to the combustion zone. The tube acts as a sealed conduit that transfers the ignited mixture without requiring penetrations through the liner, thus maintaining sealing integrity and eliminating turbulent flow associated with wall penetrations.
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
Enhances combustion efficiency by reducing fluid leakage and interference, thereby improving the overall performance and reducing NOx emissions.
Implementation Method 1
a mixing channel (114) having a venturi shape
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
An igniter 100 for a combustor 16 of a turbomachine includes a fuel inlet 102 in fluid communication with a mixing plenum 110. The mixing plenum 110 is positioned upstream of a mixing channel 126. An air inlet 104 is in fluid communication with the mixing plenum 110 and an ignition source 120 is in operative communication with the mixing channel 126. The igniter 100 may include a mounting flange 122 configured for coupling the igniter 100 to the combustor 16. The ignition source 120 may be positioned proximate to a downstream end of the mixing channel 126 and upstream of the mounting flange 122. The mixing channel 126 may define a venturi shape. The venturi shape includes a converging section 114 between an upstream end of the mixing channel 126 and a venturi throat 116.