Gearbox Gutter Volume Ratio for Lubricant Scavenging Efficiency
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Solution Overview
Problem
Existing gearbox assemblies in gas turbine engines face inefficiencies due to windage and friction losses, which also lead to heat generation and improper lubricant scavenging, resulting in reduced gearbox efficiency and potential engine performance issues.
Innovation Solution
The proposed solution involves optimizing the gutter design in the gearbox assembly by establishing a specific lubricant extraction volume ratio (LEVR) between 0.01 and 0.3, ensuring the gutter volume is appropriately sized relative to the gearbox volume, thereby maximizing lubricant scavenging while minimizing negative impacts on engine efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gutter volume is increased to improve lubricant scavenging, then lubricant extraction efficiency is improved, but the weight and volume of the gearbox assembly increases
Solution Approach 1:
The patent applies parameter changes by optimizing the gutter volume as a specific geometric parameter. The gutter volume is designed to be between 0.01 and 0.3 times the gearbox volume, which is a quantitative parameter optimization that balances lubricant scavenging efficiency with weight and space constraints. This parameter range was determined through analysis of the relationship between gutter volume and lubricant extraction performance.
2Productivity
If the gutter volume is increased to improve lubricant scavenging, then lubricant extraction efficiency is improved, but the gearbox volume increases
Solution Approach 1:
The patent optimizes the gutter volume parameter to be between 0.01 and 0.3 times the gearbox volume. This parameter change ensures that the gutter is large enough to effectively scavenge lubricant from the gearbox, yet small enough to minimize the overall volume increase of the gearbox assembly. The specific ratio range provides a balanced solution between extraction efficiency and compactness.
3Loss of energy
If lubricant flow rate is increased to reduce friction losses, then gearbox efficiency is improved, but windage losses and heat generation increase
Solution Approach 1:
The patent implements continuous lubricant circulation through the gearbox system. The lubricant is continuously supplied to the gears, performs its lubricating function, and is then continuously scavenged by the gutter and returned to the lubrication system. This continuous circulation ensures that friction losses are minimized throughout operation while the system maintains thermal balance through ongoing heat removal by the lubricant.
Solution Approach 2:
The patent employs a feedback mechanism where the lubricant scavenging system continuously monitors and removes lubricant from the gearbox, and the lubrication system adjusts lubricant supply based on operational conditions. This feedback loop ensures that the lubricant flow rate is optimized to minimize friction losses while preventing excessive windage losses and heat generation by maintaining appropriate lubricant levels and circulation.
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 approach enhances gearbox efficiency by ensuring proper lubricant scavenging, reduces power losses, and maintains a favorable balance between weight, volume, and scavenge effectiveness, thus improving overall engine performance.
Implementation Method 1
As the gears of the gearbox assembly rotate during operation, the lubricant is expelled outwardly. The lubricant is captured by a gutter.
Data Source
AI summary
A gas turbine engine includes a gearbox assembly that includes a gearbox and a gutter for collecting a gearbox lubricant scavenge flow from the gearbox. The gutter is characterized by a lubricant extraction volume ratio between 0.01 and 0.3. The lubricant extraction volume ratio defined by:VGVGB.VGis a gutter volume of the gutter and VGB is a gearbox volume. The gas turbine engine includes a lubrication system that includes a lubricant tank that stores lubricant, one or more primary gearbox lubricant supply lines, one or more secondary gearbox lubricant supply lines, and a lubricant pump for supplying the lubricant to the gearbox assembly through the primary gearbox lubricant supply lines and the secondary gearbox lubricant supply lines. The lubrication system modulates a mass flow rate of the lubricant to the gearbox assembly through the primary gearbox lubricant supply lines or the secondary gearbox lubricant supply lines.