Reverse Flow Combustor Curved Dilution Design
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Solution Overview
Problem
Conventional reverse flow combustors require a longer length for effective mixing and cooling, limiting their efficiency and applicability to higher pressure ratios due to increased cooled surface area needs.
Innovation Solution
A reverse flow combustor design featuring a straight portion, a short dilution portion with a tangency curve, and a turn portion with a decreasing cross-sectional area, which reduces the overall length and cooled surface area, allowing for more efficient mixing and operation at higher pressure ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional reverse flow combustor is used, then effective mixing and cooling can be achieved, but the combustor length and cooled surface area increase
Solution Approach 1:
The patent applies curvature by defining a tangency curve at the interface between the dilution portion and turn portion, creating a smooth transitional geometry. This curved interface optimizes flow patterns and enhances mixing effectiveness while minimizing the axial length required for the dilution process, thereby resolving the contradiction between mixing effectiveness and combustor length.
Solution Approach 2:
The patent changes the geometric parameters of the combustor by constraining the axial length of the dilution portion to be less than or equal to 20% of the dome height. This parameter optimization allows effective mixing and cooling to occur in a shortened axial distance, improving the length-to-mixing-effectiveness ratio.
2Temperature
If a conventional reverse flow combustor is used, then cooling can be achieved, but the cooled surface area increases
Solution Approach 1:
The patent optimizes the geometric parameters by limiting the dilution portion axial length to ≤20% of dome height and defining a specific tangency curve geometry. These parameter changes concentrate the cooling and mixing processes in a more compact volume, reducing the total cooled surface area required while maintaining effective temperature control.
Solution Approach 2:
The tangency curve geometry serves as an optimized template that replicates effective flow patterns in a shortened configuration. By copying and applying this specific geometric relationship throughout the design, the combustor achieves effective cooling with reduced surface area compared to conventional linear transitions.
3Weight of moving object
If the combustor length is reduced, then engine weight and cost decrease, but mixing and cooling effectiveness may be compromised
Solution Approach 1:
The curved tangency interface creates optimized flow trajectories that enhance mixing and cooling efficiency within the shortened combustor length. This geometric curvature ensures that reduced length does not compromise effectiveness, as the curved path increases the effective interaction distance between flows without increasing axial footprint.
Solution Approach 2:
The patent transitions from a primarily axial arrangement to a design that utilizes radial and angular dimensions through the tangency curve geometry. This dimensional redistribution allows mixing and cooling to occur more efficiently in non-axial directions, maintaining effectiveness while reducing axial length and associated weight.
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 minimizes the length of the combustor chamber, reduces cooling air requirements, and enables operation at higher pressure ratios while maintaining flame stabilization and ignition, resulting in a more efficient and compact engine configuration.
Implementation Method 1
a dilution portion coupling the second end to the third end and having an axial length of less than or equal to 20% of the predetermined height
Implementation Method 2
a turn portion having third and fourth ends, the fourth end defining a turbine inlet, and a decreasing cross-sectional area from the third end to the fourth end
Data Source
AI summary
An apparatus and method for a reverse flow combustor, the reverse flow combustor including a straight portion, a dilution portion and a curved portion. The reverse flow combustor receives a flow of fuel that is ignited and mixed with cooling air to form a flow of combustion gases. The flow of combustion gases travels through the reverse flow combustor to a turbine section of an engine.