Lubrication-Driven Gas Turbine Actuation System
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Solution Overview
Problem
Gas turbine engines face inefficiencies in fuel usage and actuator system design due to the need for excess fuel for both combustion and actuation, leading to larger and more power-intensive fuel pumps and potential fuel waste.
Innovation Solution
A lubrication-driven engine actuation system that supplies lubricant to actuators while minimizing fuel supply to the combustor, utilizing a centrifugal air/lubricant separator to optimize lubricant scavenging and reduce residence time in the lubricant tank, thereby reducing the size and power requirements of fuel pumps and actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If fuel is supplied for both combustion and actuation operations, then engine actuation can be achieved, but fuel pump size and power requirements increase
Solution Approach 1:
The patent extracts the actuation function from the fuel system by introducing a dedicated lubrication system. The lubrication pump provides pressurized lubricant exclusively for actuating variable engine geometries, while the fuel system is reduced to supplying only combustion fuel. This separation eliminates the need for oversized fuel pumps and complex fueldraulic actuation systems.
Solution Approach 2:
The lubrication system serves dual purposes: it provides necessary lubrication for engine components and simultaneously powers the actuation of variable engine geometries. By making the lubrication system multi-functional, the patent eliminates the separate fueldraulic system while maintaining actuation capability.
2Productivity
If excess fuel is supplied for actuation operations, then variable engine geometries can be actuated, but fuel waste increases
Solution Approach 1:
The patent extracts the actuation working fluid from the fuel supply, using lubricant instead. This allows actuation operations to proceed without consuming fuel, thereby eliminating fuel waste associated with fueldraulic systems while maintaining full actuator functionality.
3Power
If fuel pumps are sized for both combustion and actuation, then sufficient power is available, but system weight and complexity increase
Solution Approach 1:
The patent extracts the actuation power requirement from the fuel pump by introducing a separate lubrication pump. This allows the fuel pump to be sized only for combustion fuel delivery, significantly reducing its weight and power requirements, while the lubrication pump handles actuation power needs.
4Reliability
If lubricant residence time in tank is increased, then lubricant scavenging is improved, but actuator response time increases
Solution Approach 1:
The patent employs a variable speed motor to drive the centrifugal separator at different speeds based on operational requirements. During normal operation, the separator runs at high speed to quickly separate lubricant from air and minimize residence time, enabling rapid actuator response. During scavenging operations, the system can adjust speeds to optimize separation efficiency.
Solution Approach 2:
The centrifugal separator operates in periodic cycles, selectively activating to separate lubricant from air only when needed. This periodic operation minimizes the time lubricant spends in the separator, maintaining fast actuator response while ensuring adequate lubricant separation and return to the tank when required.
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 results in a 20% reduction in fuel pump size and minimum pressure, saving power at cruise and reducing fuel waste, while enabling lighter and more efficient actuator design with lower operating pressures, improving actuator performance and structural integrity.
Implementation Method 1
a centrifugal air/lubricant separator (48) selectively driven by a motor
Data Source
Figure 1
Figure 2
AI summary
A method of actuating variable engine geometries within a gas turbine engine (22) comprises: supplying lubricant to a gas turbine engine actuator system (60) to provide variable engine geometries; and supplying fuel as a burn flow only.