Flow Management Valve Layout for Negative-G Lubrication
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Solution Overview
Problem
Gas turbine engines face lubricant starvation issues during negative gravity conditions, where fluid in the main reservoir rises and interrupts lubrication to critical components, potentially damaging components like carbon seals due to lack of lubrication.
Innovation Solution
A lubrication system with a boost pump for starvation intolerant components, a scavenge pump for both intolerant and tolerant components, a make-up reservoir to adjust lubricant volume, and a flow management valve responsive to pressure sensors to redirect lubricant flow during normal and negative gravity events, ensuring continued lubrication to tolerant components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the main reservoir is used to supply lubricant to all engine components, then the system structure is simple, but during negative gravity conditions the lubricant supply to starvation intolerant components is interrupted
Solution Approach 1:
The lubrication system is divided into two separate circuits: a first circuit supplies lubricant to starvation intolerant components (carbon seals) while a second circuit supplies lubricant to starvation tolerant components. This segmentation allows each circuit to be independently controlled, ensuring that critical components receive continuous lubrication even when the aircraft experiences negative gravity conditions that would otherwise interrupt supply to the entire system.
2Reliability
If lubricant is supplied to all components during normal operation, then all components are protected, but during negative gravity events lubricant is lost from the system and supply is interrupted
Solution Approach 1:
The system includes a make-up reservoir that captures and recovers lubricant that would otherwise be lost during negative gravity events. When negative gravity conditions occur, the flow management valve redirects lubricant flow, and the make-up reservoir captures the excess lubricant, preventing it from being lost from the system. This recovered lubricant can then be returned to the system after the negative gravity event passes, maintaining lubricant availability without requiring continuous top-up.
3Device complexity
If a single pump supplies lubricant to all components, then the system is simple, but critical components cannot receive priority lubrication during negative gravity conditions
Solution Approach 1:
The pump system is segmented into a first pump dedicated to supplying lubricant to starvation intolerant components and a second pump supplying lubricant to starvation tolerant components. This segmentation ensures that during negative gravity conditions, the first pump can continue to provide priority lubrication to critical components without being affected by lubricant availability issues in the second circuit.
Solution Approach 2:
Flow management valves act as intermediaries between the pumps and the components they serve. These valves are configured to respond to negative gravity conditions by redirecting lubricant flow to ensure that starvation intolerant components receive continuous supply, while allowing the system to maintain operation by supplying tolerant components through alternative paths.
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 continuous lubrication to critical components during normal and negative gravity conditions, preventing damage and maintaining engine operation by redirecting lubricant flow and using a make-up reservoir to compensate for fluid shortages.
Implementation Method 1
the bias mechanism is configured to be responsive to a fluid pressure within the lubrication system
Implementation Method 2
a main pump is typically driven by a high pressure spool, connected through gearing, and is used to pump lubricating fluid to all such engine components
Data Source
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Figure 2B
AI summary
A lubrication system (200) is disclosed. In various embodiments, the lubrication system (200) includes a storage tank (202) configured to store a lubricant; a flow management valve (232) configured to direct the lubricant to a starvation tolerant component (210) and to a valve exit conduit (248); and a main pump (204) configured to receive the lubricant from the storage tank (202) and to pump the lubricant to the flow management valve (232) and to a starvation intolerant component (206, 208).