Variable Displacement Scavenge Pump for Gas Turbine Oil Leakage Control
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Solution Overview
Problem
Gas turbine engines face challenges in reducing oil leakage and auto-ignition risks due to inadequate lubrication flow management, particularly at low-power settings where scavenge pump operation fails to maintain sufficient suction for air curtains, leading to oil accumulation and leakage.
Innovation Solution
The system employs variable flow output pumps to dynamically adjust lubricant flow, allowing the scavenge pump to generate a selected level of suction and create a partial vacuum in the engine compartment, reducing oil leakage by independently adjusting the flow output of the scavenge pump relative to the pressure pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If fixed displacement pumps driven by a common drive shaft are used, then space and weight are saved, but the ability to maintain sufficient suction for air curtains at low-power settings deteriorates
Solution Approach 1:
The patent applies variable displacement pumps that can dynamically adjust their flow output based on engine operating conditions. The scavenge pump's displacement can be varied to maintain sufficient suction for air curtains across the full range of engine power settings, from idle to full power, resolving the contradiction between simplified fixed-displacement design and reliable air curtain maintenance.
Solution Approach 2:
The patent changes the operational parameters of the scavenge pump by implementing variable displacement capability. This allows the pump to adjust its flow rate and suction characteristics in response to varying engine conditions, particularly maintaining adequate suction at low-power settings where fixed-displacement pumps fail to maintain air curtains.
2Device complexity
If the scavenge pump operates at fixed displacement, then the system is simpler, but oil leakage increases at low-power settings due to inadequate suction
Solution Approach 1:
The scavenge pump is designed with variable displacement capability, allowing it to dynamically adjust its operational characteristics. At low-power settings, the pump reduces its displacement to maintain the suction necessary for air curtains, thereby preventing oil leakage without requiring complex additional control systems.
Solution Approach 2:
The system incorporates feedback mechanisms where the scavenge pump's displacement is adjusted based on engine operating conditions and suction requirements. This feedback control ensures that the pump maintains adequate suction to prevent oil leakage while adapting to varying power settings, resolving the contradiction between system simplicity and leakage prevention.
3Object-generated harmful factors
If variable flow output pumps are used to independently adjust scavenge pump flow, then oil containment improves, but device complexity increases
Solution Approach 1:
The patent implements variable displacement pumps that can independently adjust their flow output. The scavenge pump's displacement can be varied separately from the pressure pump, allowing precise control of suction and air curtain maintenance. This dynamic control improves oil containment while keeping the complexity manageable through integrated pump design.
Solution Approach 2:
The patent segments the control of the two pumps by allowing independent displacement adjustment of the scavenge pump from the pressure pump. This segmentation enables the scavenge pump to be optimized for maintaining air curtains and preventing leakage, while the pressure pump handles oil delivery, dividing the control functions to improve containment without excessive complexity.
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 effectively reduces oil leakage and maintains air curtain integrity across various engine operational conditions, enhancing oil containment and reducing the risk of auto-ignition by creating a negative pressure environment within the compartment.
Implementation Method 1
at least temporarily increasing a rate at which oil is moved with the scavenge pump by a greater amount than a rate at which oil is moved with the pressure pump to create at least a partial vacuum to negatively pressurize the compartment
Implementation Method 2
moving oil from a tank to a compartment using a pressure pump
Implementation Method 3
moving oil from the compartment to the tank using a scavenge pump
Data Source
AI summary
A method of oil flow management for a gas turbine engine includes moving oil from a tank to a compartment using a pressure pump, moving oil from the compartment to the tank using a scavenge pump, and at least temporarily increasing a rate at which oil is moved with the scavenge pump by a greater amount than a rate at which oil is moved with the pressure pump to create at least a partial vacuum to negatively pressurize the compartment to reduce oil leakage.