Turbine Engine Flow Path Geometry for Fan Efficiency
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Solution Overview
Problem
Turbine engine fan performance is limited by inefficiencies in airflow and surge margin, leading to suboptimal fuel consumption and engine efficiency.
Innovation Solution
The introduction of a turbine engine flow path geometry featuring an annular region with a divergent and convergent profile, where the flow path expands and contracts radially to align with the fan blades, reducing fan blade incidence and enhancing flow capacity, with angles θ and α optimizing fluid flow alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a conventional linear flow path is used, then the structure is simple, but fan efficiency and surge margin are limited
Solution Approach 1:
The flow path geometry transitions from a static linear profile to a dynamic variable profile that expands and contracts radially. The expanded portion has a continuously increasing radial displacement while the contracted portion has a continuously decreasing radial displacement, allowing the flow path to adapt to different operating conditions and optimize fan performance across varying surge margins.
Solution Approach 2:
The patent changes the geometric parameters of the flow path by introducing variable radial displacement profiles. The expanded portion increases radial displacement continuously downstream, while the contracted portion decreases radial displacement continuously downstream. This parameter variation optimizes flow alignment with fan blades, reducing incidence and enhancing flow capacity to improve fan efficiency by approximately 0.7%.
2Productivity
If the flow path is expanded and contracted to align with fan blades, then fan efficiency increases, but manufacturing complexity increases
Solution Approach 1:
The flow path is segmented into distinct functional portions: a forward portion, an expanded portion with continuously increasing radial displacement, and a contracted portion with continuously decreasing radial displacement. This segmentation allows each portion to be optimized independently for its specific function while maintaining overall manufacturability through modular design approaches.
Solution Approach 2:
The patent employs curved surfaces and smooth transitions in the expanded and contracted portions to optimize flow alignment. The continuously varying radial displacement profiles create smooth curvature that reduces flow separation and shock strength, while the geometric continuity ensures manufacturability by avoiding abrupt changes that would complicate fabrication.
3Object-affected harmful factors
If angles θ and α are optimized for flow alignment, then shock strength is reduced, but design precision requirements increase
Solution Approach 1:
The patent optimizes the angles θ and α of the flow path portions to reduce shock strength. The expanded portion is inclined at angle θ with respect to the axis while the contracted portion is declined at angle α with respect to the axis, where α ≥ θ. This angular optimization aligns the flow path with fan blade geometry, reducing incidence and shock strength while maintaining practical manufacturing precision through defined angular parameters.
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 geometry increases fan efficiency by approximately 0.7% and surge margin by 1.6%, leading to improved fuel consumption and reduced shock strength, while being easily integratable into existing engines without significant redesign.
Implementation Method 1
the expanded portion having a continuously increasing radial displacement from the axis as the expanded portion extends downstream
Implementation Method 2
the contracted portion having a continuously decreasing radial displacement from the axis as the contracting portion extends downstream
Implementation Method 3
the outer boundary of the flow path at the expanding portion is inclined θ with respect to the axis and the outer boundary of the flow path at the contracting portion is declined α with respect to the axis
Data Source
Figure 1
Figure 2A
Figure 2B
AI summary
A turbine engine casing flow-path segment that is locally diffusing, followed by a flow-path segment contracting in the vicinity of a fan blade. This contraction accelerates the fluid flow axially forward of the fan blade leading edge at the tip and converges with the linear flow-path aft of the fan blade leading edge but forward of the fan blade trailing edge. More diffused fluid flow results in increased flow capacity of the fan, and increased fan efficiency.