Turbofan Casing Strut Flow Channel for Lubricant Scavenging
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Solution Overview
Problem
Turbofan engines face challenges in efficiently scavenging lubricating fluid from the fan frame cavity due to limited radial space, which affects inlet diffusion loss and fuel burn efficiency.
Innovation Solution
A casing design with an inner hub, intermediate casing, outer casing, and struts with flow channels and fluid scoops that facilitate the collection and recirculation of lubricating fluid, including a fluid sump and collector system to enhance scavenging efficiency while reducing weight and space usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If bolt-on scoops are used for scavenging lubricating fluid, then fluid collection is achieved, but radial space within the fan frame cavity is increased
Solution Approach 1:
The patent combines the fluid scoop and the casing into a single integrated structure. The scoop is formed as an integral part of the casing rather than being a separate bolt-on component, thereby eliminating the need for additional radial space while maintaining fluid collection capability. This merging of components directly resolves the contradiction between ease of manufacture and volume consumption.
Solution Approach 2:
The casing is designed to serve multiple functions: it provides structural support, contains the lubricating fluid, and acts as the scavenging scoop itself. By making the casing multi-functional, the patent eliminates the need for separate dedicated scoop components, thereby reducing radial space requirements while maintaining all necessary functions.
2Volume of moving object
If radial height of components is reduced to save space, then radial space utilization is improved, but manufacturing complexity increases
Solution Approach 1:
The casing is divided into multiple functional zones: an inner hub portion, an intermediate portion with flow channels, and an outer portion. This segmentation allows each zone to be optimized for its specific function while maintaining overall compactness. The segmentation reduces the need for complex internal structures by distributing functions across different radial zones.
Solution Approach 2:
The patent utilizes the axial dimension (length of the casing) to accommodate complex scavenging functions that would otherwise require increased radial height. Flow channels and internal structures are arranged axially rather than radially, allowing compact radial packaging while maintaining functional complexity through axial extension.
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 solution enables efficient scavenging of lubricating fluid, reducing inlet diffusion loss and improving fuel burn efficiency by optimizing the use of radial space within the fan frame cavity.
Implementation Method 1
At least one strut of the plurality of struts includes a flow channel extending therethrough
Implementation Method 2
The casing also includes a fluid scoop defined within the inner hub, and a collector that couples the fluid scoop in flow communication with the flow channel
Data Source
AI summary
A casing for use in a turbofan engine is provided. The casing includes an inner hub including a first fluid opening defined at bottom dead center of the casing. The casing also includes an intermediate casing positioned radially outward from the inner hub, an outer casing positioned radially outward from the intermediate casing, and struts spaced circumferentially about the inner hub and extending between the inner hub and the outer casing. The struts include a first strut and a second strut positioned on opposing sides of bottom dead center of the casing such that a first fluid sump is defined between the inner hub, the intermediate casing, and the first and second struts. At least one of said first and second struts includes a flow channel extending therethrough such that a fluid flow path is defined from the first fluid opening, through the first fluid sump, and through the flow channel.