Geared Turbofan Drive Train Form Locking Connection
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Solution Overview
Problem
Gas turbine engines with geared turbofan arrangements face challenges in mitigating damage from mechanical failures such as shaft breakage, rotor-casing contact, and bearing seizure, which can lead to uncontrolled loads and potential engine shutdown.
Innovation Solution
Incorporating a form locking connection device, such as a clutch or spline connection, within the drive train to enable controlled disengagement of engine parts from the drive train during mechanical failures, along with load stops to manage axial loads, and using detection means for overspeeding to automatically shut down the engine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a geared turbofan arrangement is used to improve engine performance, then propulsion efficiency is improved, but vulnerability to mechanical failure increases
Solution Approach 1:
The drive train is segmented into separable components with form locking connection devices that enable controlled disengagement. The propulsive fan, gearbox, and turbine are divided into modules that can be independently disconnected through clutch mechanisms or spline connections, allowing failure isolation while maintaining overall system functionality.
Solution Approach 2:
Form locking connection devices act as intermediary elements between the turbine and propulsive fan. These devices include clutches positioned in torque carrying shafts and spline connections in torque bearing couplings, serving as mediators that can engage or disengage power transmission based on operational conditions or failure detection.
2Duration of action of moving object
If the drive train remains connected during failure to maintain power transmission, then propulsion continuity is maintained, but damage propagation increases
Solution Approach 1:
The system applies preliminary anti-action by pre-positioning form locking connection devices and load stops that automatically activate upon failure detection. These devices are designed to disengage or engage in predetermined sequences that counteract damage propagation before it can spread through the drive train, protecting critical components from catastrophic failure.
Solution Approach 2:
Load stops are positioned beforehand in the drive train to cushion and limit the transmission of abnormal loads. These load stops act as protective barriers that engage prior to potential damage, absorbing or redirecting excessive forces generated during mechanical failures such as shaft breakage or bearing seizure.
3Reliability
If form locking connection devices are added to enable controlled disengagement, then failure mitigation is improved, but device complexity increases
Solution Approach 1:
The form locking connection devices are designed with multi-functionality to reduce overall complexity. The same clutch mechanisms and spline connections serve both normal operational engagement/disengagement and failure mitigation functions. Load stops simultaneously protect against abnormal loads and facilitate controlled disengagement sequences, reducing the need for separate dedicated components.
Solution Approach 2:
Multiple functions are merged into integrated components. The form locking connection devices combine torque transmission, controlled disengagement, and failure protection functions in single elements. The load stops are integrated into the existing shaft and coupling structures, merging protection functions with load-bearing components rather than adding separate systems.
4Strength
If load stops are positioned to retain the propulsive fan, then component protection is improved, but axial load bearing complexity increases
Solution Approach 1:
The load stops are designed to self-activate based on the direction and magnitude of axial loads during failure conditions. The load stops automatically engage when abnormal axial forces are detected, retaining the propulsive fan without requiring external actuation systems. This self-service mechanism reduces complexity by eliminating the need for sensors, actuators, or control systems specifically for load stop activation.
Data Source
AI summary
A gas turbine engine with a geared turbofan arrangement with a gearbox in a drive train driven by a turbine, a driving side of the gearbox being driveably connected with a propulsive fan, is provided. The gas turbine includes at least one form locking connection device in a drive train enabling a controlled disengagement of at least one engine part from the drive train in case of a mechanical failure of the gas turbine engine or a part thereof and wherein the at least one form locking connection device is positioned in a torque carrying shaft or a torque carrying part of a shaft and/or wherein the at least one form locking connection device is positioned between the torque bearing coupling of the gearbox with the fan shaft and a torque carrier of the gearbox and at least one load stop for bearing an essential axial load.