Spring-Driven Auxiliary Lubrication for Windmilling Turbine Engines
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Solution Overview
Problem
Turbine engines face challenges in maintaining adequate lubrication to rotating components during windmilling conditions, particularly due to insufficient lubricant supply from primary pumps, which can lead to journal bearing failure and gearbox issues.
Innovation Solution
An auxiliary lubrication system powered by a strain energy storage system, utilizing a torsional spring to store energy during normal operation and release it to operate an auxiliary pump during shutdown or windmilling, ensuring continuous lubricant supply to rotating components regardless of propulsor direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a primary pump supplies lubricant during normal operation, then lubrication is provided during operational phases, but lubricant supply becomes insufficient during windmilling or shutdown conditions
Solution Approach 1:
The strain energy storage system accumulates energy during normal operation before windmilling or shutdown occurs. This preliminary energy storage enables the auxiliary pump to operate independently during windmilling conditions, ensuring continuous lubricant supply without requiring external power sources or complex control systems.
Solution Approach 2:
The strain energy storage system acts as an intermediary between the primary pump and the auxiliary pump. It stores energy during normal operation and releases it to drive the auxiliary pump during windmilling, bridging the gap between operational phases and ensuring continuous lubrication without direct mechanical coupling.
2Reliability
If the auxiliary pump is powered by strain energy storage, then continuous lubrication during windmilling is achieved, but system complexity increases
Solution Approach 1:
The strain energy storage system is driven by the propulsor shaft during normal operation, using the existing rotational energy to charge the spring. During windmilling, the same spring automatically discharges to power the auxiliary pump without requiring external control systems, sensors, or additional power sources, making the system self-regulating and reducing operational complexity.
Solution Approach 2:
The auxiliary pump and strain energy storage system are integrated into the existing lubrication architecture, sharing common components such as the propulsor shaft drive and lubricant delivery pathways. This merging approach minimizes additional hardware while achieving the dual-functionality of normal operation and windmilling support.
3Device complexity
If the primary pump alone supplies lubricant, then system simplicity is maintained, but bearing failure risk increases during windmilling
Solution Approach 1:
The strain energy storage system prepares energy reserves in advance during normal operation, creating a buffer that activates automatically during windmilling conditions. This beforehand cushioning ensures that lubricant supply is maintained even when the primary pump cannot operate, preventing bearing failure without requiring complex active control systems.
Solution Approach 2:
The auxiliary pump, powered by the strain energy storage system, ensures continuous lubricant delivery during windmilling and shutdown phases. This continuity of useful action eliminates the harmful effect of lubrication interruption while maintaining system simplicity by using passive energy storage rather than active control mechanisms.
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 system ensures consistent lubrication to rotating components during normal operation and windmilling, preventing bearing and gearbox failures by maintaining lubricant flow independently of propulsor shaft rotation direction and reducing system complexity.
Implementation Method 1
a strain energy storage system comprising a spring drivingly coupled to the auxiliary pump shaft, wherein the spring stores strain energy during normal operation of the turbine engine and releases the strain energy when the propulsor is windmilling, to rotate the auxiliary pump shaft to power the auxiliary pump
Data Source
AI summary
A lubrication system for a turbine engine. The turbine engine includes a propulsor and one or more rotating components. The lubrication system includes a sump, a primary lubrication system, an auxiliary lubrication system, and a strain energy storage system. The sump stores lubricant therein. The primary lubrication system supplies the lubricant from the sump to the one or more rotating components during normal operation of the turbine engine. The auxiliary lubrication system includes an auxiliary pump including an auxiliary pump shaft. The strain energy storage system includes a spring drivingly coupled to the auxiliary pump shaft. The spring stores strain energy during normal operation of the turbine engine and releases the strain energy when the propulsor is windmilling to rotate the auxiliary pump shaft to power the auxiliary pump such that the auxiliary pump pumps the lubricant from the sump to the one or more rotating components.