Azimuthal Diffuser Vane Alignment for Water Management
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Solution Overview
Problem
Aircraft engines face accidental combustion chamber extinctions due to water ingestion during inclement weather or high humidity, which existing solutions like air diversion from compressors or fairings covering the combustion chamber are insufficient to prevent, as they do not effectively manage water accumulation and its impact on combustion.
Innovation Solution
An azimuthal setting is introduced between the diffuser vanes and fuel injectors, where the angular position of the diffuser vanes is optimized to direct water away from the injectors, concentrating it to pass between them without harming combustion, by aligning the flow trajectories from the diffuser blades with the injectors at specific angular distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If air intakes in compressors are used to remove water-laden air, then water removal capability is improved, but the solution is not always sufficient and not present in all engines
Solution Approach 1:
The diffuser is segmented into multiple fixed blades arranged in a circle, with each blade positioned at specific angular intervals. This segmentation allows the water-laden flow to be divided and directed into specific sectors, with water being concentrated in inter-injector regions while dry air is directed toward injectors, providing a structured approach to water management that can be applied across different engine types
2Object-affected harmful factors
If a shroud covering the combustion chamber is added to direct water runoff, then water protection is improved, but device complexity and optimization difficulty increase
Solution Approach 1:
The harmful water-laden air is extracted from the main flow path by the diffuser blade geometry, which directs it into specific sectors between injectors. The fixed blades act as flow separators, extracting water from the combustion air stream and channeling it away from critical injection zones, thereby protecting combustion without requiring additional protective structures
3Object-affected harmful factors
If diffuser vanes are azimuthally aligned with injectors to limit water accumulation, then water management is improved, but manufacturing precision requirements increase
Solution Approach 1:
The diffuser blades are positioned asymmetrically with respect to the injectors, with each blade's trailing edge oriented at a specific angular distance from adjacent injectors. This asymmetric angular arrangement creates preferential flow paths that naturally direct water-laden streams into inter-injector regions while channeling drier air toward injectors, providing effective water management through geometric design rather than precise angular alignment
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 solution effectively prevents water from reaching the combustion chamber, maintaining engine operation by ensuring dry air reaches the injectors, thus preventing combustion extinction and ensuring reliable engine performance in wet conditions.
Implementation Method 1
air outside the intake stream, which is laden with water due to the centrifugal force produced by the compressors
Implementation Method 2
the water concentrated in the flow passes in front of the lower surface of the diffuser blades due to its greater inertia
Data Source
Figure 1
Figure 2~3
AI summary
The fixed vanes (15) of a diffuser (14) are set to an azimuth angle (a) with respect to the injectors (9) of a combustion chamber so that the paths (35) leading from the trailing edges (34) pass through the gaps (38) between injectors (9), preferably mid-way between same, so that these portions of the flow, which may contain condensed water, do not affect the initiation of combustion.