Combustor Mixing Joint Flow Disruption Surface
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Solution Overview
Problem
The existing design of annular combustors in gas turbine engines leads to significant mixing losses due to stagnant flow regions and non-uniform combustor flows, which result in increased pressure losses and reduced efficiency, as the combustion streams do not mix adequately before entering the turbine.
Innovation Solution
A mixing joint with a flow disruption surface is introduced between adjacent can combustors to promote the mixing of combustion streams, featuring geometries such as chevron, lobed, or fluidics configurations that enhance mixing in the low velocity region downstream of the combustors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a blunt joint is used between adjacent can combustors, then the structural simplicity and ease of manufacture are improved, but stagnant flow regions and non-uniform flows are created downstream, leading to increased mixing losses and pressure losses
Solution Approach 1:
The joint between adjacent can combustors is segmented into multiple surfaces including a first flow disruption surface on one combustor and a second flow disruption surface on the adjacent combustor. These segmented surfaces work together to disrupt stagnant flow regions and promote mixing, resolving the contradiction by replacing a simple blunt joint with a multi-surface configuration that maintains manufacturability while reducing mixing losses
Solution Approach 2:
The flow disruption surfaces extend in the axial direction beyond the blunt joint, adding a dimensional element to the joint design. This axial extension creates flow disruption without significantly increasing manufacturing complexity, as the surfaces can be integrated into the existing combustor structure rather than requiring completely new components
2Length of moving object
If the axial distance between combustor exit and turbine leading edge is kept small, then the compactness and space utilization are improved, but adequate mixing of combustion streams cannot occur, resulting in non-uniform flows and increased mixing losses
Solution Approach 1:
Mixing action is initiated at the joint between combustors through flow disruption surfaces, which create turbulence and promote mixing before the flows reach the turbine. This preliminary mixing action occurs in the limited axial space available, preventing the formation of large stagnant regions and reducing subsequent mixing losses in the turbine
Solution Approach 2:
The flow disruption surfaces act as an intermediary element between the combustor exit and the turbine inlet. These surfaces actively promote mixing in the intermediate region, enabling adequate mixing to occur within the constrained axial distance without requiring increased spacing between components
3Loss of energy
If flow disruption surfaces are added to the combustor joint, then mixing losses are reduced and flow uniformity is improved, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
Flow disruption surfaces are applied locally at the joint region between adjacent combustors rather than throughout the entire combustor structure. This localized application reduces the overall device complexity by concentrating the flow control function only where it is most needed, minimizing the impact on manufacturing while achieving the desired mixing improvement
Solution Approach 2:
The flow disruption surfaces serve multiple functions simultaneously: they disrupt stagnant flow regions, promote mixing between adjacent combustor streams, and can be integrated into the existing combustor joint structure. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity
4Speed
If strong acceleration occurs in the stage one nozzle, then the Mach number is increased to about 1.0, but the non-uniformities in the flow field are exaggerated, creating more mixing losses downstream
Solution Approach 1:
Mixing is promoted in advance of the nozzle acceleration through flow disruption surfaces at the combustor joint. By establishing mixing action before the strong acceleration occurs, the flow uniformity is improved entering the nozzle, which prevents the acceleration from exaggerating non-uniformities and creating excessive mixing losses downstream
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 significantly reduces mixing losses by improving the uniformity of the flow field before entering the turbine, thereby minimizing overall pressure losses without increasing the axial distance between the combustors and the turbine, leading to enhanced system performance and efficiency.
Implementation Method 1
a flow disruption surface positioned about the first wall and the second wall to promote mixing of the first combustion flow and the second combustion flow
Implementation Method 2
promote mixing of the first combustion flow and the second combustion flow
Data Source
AI summary
A mixing joint for adjacent can combustors may include a first can combustor with a first combustion flow and a first wall, a second can combustor with a second combustion flow and a second wall, and a flow disruption surface positioned about the first wall and the second wall to promote mixing of the first combustion flow and the second combustion flow.