Oil Cooling Fan Coupling for Gas Turbine Engine Efficiency
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Solution Overview
Problem
Existing systems for driving oil cooling fans in gas turbine engines often compromise efficiency during different modes of operation, such as flight and ground modes.
Innovation Solution
A system comprising a coupling device to transmit motive power from the power turbine shaft to the oil cooling fan during operation and decouple it during non-operation, along with an alternate source of motive power to drive the fan, such as an electric motor, to maintain efficient operation across modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil cooling fan is driven by the power turbine shaft during all modes of operation, then the fan is always powered, but the engine efficiency is compromised during ground mode where the power turbine shaft is locked
Solution Approach 1:
The coupling device dynamically changes its state based on operating mode: it couples the power turbine shaft to the fan during flight mode when the shaft is rotating, and decouples them during ground mode when the shaft is locked. This dynamic adaptation allows the system to maintain fan operation reliability when needed while avoiding energy losses when the power source is unavailable or inefficient.
Solution Approach 2:
The coupling device acts as an intermediary between the power turbine shaft and the cooling fan. It selectively transmits motive power from the shaft to the fan only when appropriate (during flight mode), and blocks power transmission when the shaft is locked (during ground mode), thereby preventing energy losses while ensuring fan operation when required.
2Loss of energy
If the oil cooling fan is decoupled from the power turbine shaft during ground mode, then engine efficiency is improved, but the fan cannot be powered during modes where the shaft is locked
Solution Approach 1:
The system achieves multi-functionality by providing two power sources for the cooling fan: the power turbine shaft during flight mode and an alternate power source during ground mode. This universal power supply capability ensures the fan can operate reliably across all operating modes, adapting to the availability of different power sources.
Solution Approach 2:
The coupling device serves as a mediator that directs power from different sources to the fan based on operating mode. During flight mode, it couples the power turbine shaft to the fan; during ground mode, it decouples the shaft and enables connection to an alternate power source, ensuring continuous fan operation adaptability across all modes.
3Device complexity
If a single power source is used to drive the oil cooling fan, then the system is simpler, but it cannot accommodate different modes of operation efficiently
Solution Approach 1:
The power transmission system dynamically adapts its configuration based on operating mode. The coupling device transitions between coupled and decoupled states, and the system switches between primary and alternate power sources as needed. This dynamic behavior enables the system to accommodate different operating modes efficiently while maintaining manageable complexity through automated control.
Data Source
AI summary
Systems and methods for driving an oil cooling fan (36) of a gas turbine engine (10) during different modes of operation of the gas turbine engine (10) are described. A system may include a coupling device (40) configured to: transmit motive power from a power turbine shaft (22) of the gas turbine engine (10) to the oil cooling fan (36) during a first mode of operation where the power turbine shaft (22) is turning, and to decouple the oil cooling fan (36) from the power turbine shaft (22) during a second mode of operation where the power turbine shaft (22) is prevented from turning. An alternate source (42) of motive power may be configured to drive the oil cooling fan (36) during the second mode of operation.