Passive Auxiliary Lubrication for Gearbox Pump Failure
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Solution Overview
Problem
Gas turbine engine gearbox assemblies face lubrication challenges when the primary lubrication system fails or loses pressure, leading to inadequate lubrication of components such as gears and journal bearings.
Innovation Solution
A passive auxiliary lubrication system that includes an auxiliary tank passively pressurized by a spring-loaded piston or bleed air, which supplies lubricant to the gearbox assembly without the need for a pump, ensuring continuous lubrication during primary system failures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primary lubrication system with a pump is used to supply lubricant to the gearbox assembly, then lubrication can be provided under normal operating conditions, but the system becomes vulnerable to failure when the pump loses pressure or fails
Solution Approach 1:
The auxiliary tank is pre-filled with lubricant and pre-pressurized using a spring-loaded piston or bleed air system before any failure occurs. This preliminary preparation ensures that when the primary pump fails, the auxiliary system can immediately supply lubricant without requiring activation or filling operations during the emergency.
Solution Approach 2:
The auxiliary tank acts as an intermediary lubrication system between the primary pump and the gearbox assembly. When the primary system fails, the auxiliary tank mediates the lubrication supply by directly delivering lubricant to the gearbox through a separate feed line, bypassing the failed primary system.
2Reliability
If an auxiliary lubrication system is added to backup the primary system, then lubrication reliability improves during failures, but the overall system complexity increases
Solution Approach 1:
The auxiliary tank is designed to be self-pressurizing using either a spring-loaded piston that automatically expands to pressurize the lubricant or bleed air from the engine that automatically fills and pressurizes the tank. This self-service capability eliminates the need for external pumps or complex control systems to activate the auxiliary system during failures.
Solution Approach 2:
The auxiliary lubrication system is extracted as a separate, independent subsystem with its own tank, pressurization mechanism, and feed line. This modular extraction allows the auxiliary system to operate independently of the primary system while maintaining a relatively simple overall architecture rather than integrating complex backup mechanisms into the primary system.
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 passive auxiliary lubrication system effectively bypasses the primary pump failure by using stored pressure to deliver lubricant to critical gearbox components, maintaining operational integrity during abnormal events.
Implementation Method 1
The auxiliary tank includes a spring-loaded piston that passively pressurizes the lubricant in the auxiliary tank
Implementation Method 2
The auxiliary tank receives bleed air from a compressor of the engine to passively pressurize the lubricant
Data Source
AI summary
A passive auxiliary lubrication system for supplying lubricant to a gearbox assembly of an engine. The passive auxiliary lubrication system includes an auxiliary tank for storing lubricant. The auxiliary tank is passively pressurized. The passive auxiliary lubrication system also includes an auxiliary tank feed line fluidly coupled with the auxiliary tank and a primary lubrication system. The lubricant is supplied to the auxiliary tank from the primary lubrication system through the auxiliary tank feed line and the lubricant is passively pressurized in the auxiliary tank. The passive auxiliary lubrication system further includes an auxiliary supply line fluidly coupled with the auxiliary tank and the gearbox assembly. The lubricant in the auxiliary tank is supplied to the gearbox assembly through the auxiliary supply line.