Canted Combustor Liners for Gas Turbine Flowpath Length
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Solution Overview
Problem
Gas turbine engine combustor assemblies face challenges such as reduced flowpath length, pressure losses, flow non-uniformity, and decreased backflow margins, which affect performance, durability, and emissions output, particularly in power generating gas turbine engines derived from aero engines.
Innovation Solution
A combustor assembly design featuring an angled configuration with extended inner and outer liners, a dome assembly, and a bulkhead assembly that defines a plenum and primary flowpath, along with a fuel injector assembly and fairings to enhance flow uniformity and reduce pressure losses, utilizing the entire flowpath air for cooling and combustion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If aero gas turbine engine design is used to decrease axial and radial dimensions, then engine size is reduced, but flowpath length for fuel-air mixing is insufficient
Solution Approach 1:
The combustor assembly is configured at a cant angle relative to the longitudinal centerline of the engine, transforming the flowpath from a purely axial arrangement to a three-dimensional angled configuration. This dimensional change allows the flowpath to extend both axially and radially, effectively increasing the flowpath length for fuel-air mixing while maintaining compact engine dimensions. The angled inner and outer liners create an extended combustion chamber that utilizes spatial arrangement in multiple dimensions to resolve the contradiction between compact size and sufficient mixing length.
2Power
If known combustor assemblies are used, then combustion function is provided, but pressure losses are significant
Solution Approach 1:
The combustor assembly employs curved inner and outer liners that follow a cant angle rather than straight axial lines. This curvature allows the flow to follow a smoother path through the combustion chamber, reducing flow separation and turbulence-induced pressure losses. The dome assembly with its curved geometry further facilitates smooth flow transitions, minimizing energy losses while maintaining effective combustion.
Solution Approach 2:
The combustor assembly is divided into distinct functional segments including the inner liner, outer liner, dome assembly, and bulkhead assembly. Each segment is optimized for its specific function while working together to minimize overall pressure losses. The segmentation allows for optimized flow paths in different zones of the combustor, reducing localized pressure drops.
3Power
If known combustor assemblies are used, then combustion is achieved, but flow uniformity is poor
Solution Approach 1:
The inner and outer liners are configured with specific cant angles that create localized flow control zones. The bulkhead assembly with its contoured fairing provides localized flow conditioning at critical positions within the combustor. These localized geometric features work together to distribute flow more uniformly across the combustion chamber, ensuring consistent combustion conditions throughout the assembly.
4Power
If known combustor assemblies are used, then combustion function is provided, but backflow margins are decreased
Solution Approach 1:
The combustor assembly utilizes asymmetric cant angles for the inner and outer liners relative to the engine axis, creating an asymmetric flow path configuration. This asymmetry, combined with the contoured bulkhead fairing, directs flow in a manner that maintains higher backflow margins by preventing reverse flow into critical combustion zones. The asymmetric geometry optimizes flow direction to protect the combustion chamber from backflow while maintaining combustion efficiency.
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 design increases flowpath length, reduces pressure losses, and improves flow uniformity and backflow margins, leading to enhanced performance, durability, and emissions reduction in gas turbine engines.
Implementation Method 1
The inner casing fairing is extended at least partially co-directional with the inner liner and directs the flow of oxidizer from between the outer casing and the inner casing along the forward direction to the aft direction between the outer casing and the inner liner
Implementation Method 2
utilizing the entire flowpath air for cooling and combustion
Implementation Method 3
enables sufficient fuel-air mixing necessary to meet or exceed emissions regulations
Data Source
Figure 1
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AI summary
The present disclosure is directed to a combustion section (26) for a gas turbine engine. The combustion section (26) includes a combustor assembly (50), an outer casing (110), a fuel injector assembly (70), and an inner casing (120). The combustor assembly (50) includes an inner liner (52) and an outer liner (54) each extended at least partially along a lengthwise direction and at an acute angle relative to the longitudinal centerline. The combustor assembly (50) further includes a dome assembly (57) extended between the inner liner (52) and the outer liner (54). The dome assembly (57), the inner liner (52), and the outer liner (54) together define a combustion chamber (62) therebetween. The combustor assembly (50) still further includes a bulkhead assembly (56) defining a plurality of walls coupled to the inner liner (52) and generally surrounding the outer liner (54) and dome assembly (57). At least a portion of the bulkhead assembly (56) is extended at least partially along a forward direction and defines a plenum (71) between the bulkhead assembly (56) and the dome assembly (57). The outer casing (110) surrounds the combustor assembly (50) and is extended at least partially co-directional to the combustor assembly (50). The fuel injector assembly (70) is extended through the outer casing (110), the bulkhead assembly (56), and the dome assembly (57). The inner casing (120), the outer casing (110), and the combustor assembly (50) together define a primary flowpath (105) in direct fluid communication with the combustion chamber (62). The primary flowpath (105) is extended at least along a forward direction and an aft direction defined by inner casing (120), the outer casing (110), and the combustor assembly (50). An oxidizer flows through the primary flowpath (105) in serial flow through the plenum (71) and the fuel injector assembly (70) into the combustion chamber (62).