Lubricant Strut Flowpaths for Maneuver-Stable Turbine Engine Scavenging
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Solution Overview
Problem
Turbine engines face significant packaging challenges due to the large amount of lubricant required for gearbox assemblies, leading to increased weight, reduced efficiency, and lubricant interruptions during aircraft maneuvers, which can cause excessive heat generation and gear submersion.
Innovation Solution
A lubrication system with multiple lubricant struts positioned outside the core air flowpath and a common scavenge reservoir ensures continuous lubricant circulation and prevents interruptions during aircraft maneuvers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large amount of lubricant is used for gearbox assembly, then lubrication reliability is improved, but weight increases and engine efficiency decreases
Solution Approach 1:
The lubrication system is segmented into multiple lubricant struts (first lubricant strut, second lubricant strut, third lubricant strut) that are circumferentially spaced around the core air flowpath. Each strut independently directs lubricant from the sump to the scavenge reservoir, ensuring that lubrication function is distributed and maintained even if one strut becomes ineffective or during aircraft maneuvers.
2Reliability
If a large amount of lubricant is used for gearbox assembly, then lubrication reliability is improved, but engine efficiency decreases
Solution Approach 1:
The lubricant management function is extracted from the core air flowpath by positioning the lubricant struts and scavenge reservoir outside the core air flowpath. This separation prevents lubricant from interfering with the aerodynamic efficiency of the core flow while maintaining adequate lubrication for the gearbox assembly.
3Volume of moving object
If lubricant is positioned in the core air flowpath, then packaging space is reduced, but lubricant interruptions occur during aircraft maneuvers
Solution Approach 1:
The lubricant struts are positioned in a circumferential arrangement around the core air flowpath rather than within it, utilizing the radial dimension outside the core flow. This spatial reconfiguration maintains compact packaging while ensuring lubricant continuity during aircraft maneuvers by distributing struts around the entire circumference.
4Reliability
If multiple lubricant struts are positioned outside the core air flowpath, then lubrication continuity is maintained during maneuvers, but device complexity increases
Solution Approach 1:
Multiple lubricant struts (first, second, and third lubricant struts) are merged into a unified lubrication system that shares common components including the sump, scavenge reservoir, and lubricant circulation pathway. This merging approach maintains lubrication continuity during maneuvers while avoiding the full complexity of completely separate lubrication systems for each strut.
Data Source
AI summary
A turbine engine includes a turbo-engine, a fan, a frame, and a lubrication system. The turbo-engine includes a core air flowpath. The fan is drivingly coupled to the turbo-engine. The frame supports the core air flowpath and includes a plurality of lubricant struts that extend through the core air flowpath. The lubrication system includes a sump having a lubricant therein, a scavenge reservoir, and a lubricant strut flowpath disposed through each of the plurality of lubricant struts. The lubricant strut flowpath is in fluid communication with the sump and the scavenge reservoir. The lubricant strut flowpath of each of the plurality of lubricant struts directs the lubricant from the sump to the scavenge reservoir.