Gas Turbine Cone Clutch Coupler for Engine Start
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing gas turbine engine start systems face inefficiencies in coupling shafts during the engine start sequence, which affects the engine's ability to achieve a sufficient pressure ratio for combustion efficiently.
Innovation Solution
A gearbox with a cone clutch mechanism is used to selectively couple the high pressure and intermediate pressure spools, allowing them to rotate at the same speed during the engine start sequence, and then decouple when the engine reaches the necessary pressure ratio, utilizing a working fluid pressure to engage and disengage the clutch.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional shaft coupling system is used, then the structure is simple, but the engine start efficiency is poor and combustion pressure ratio is insufficient
Solution Approach 1:
The coupling system is segmented into multiple independent components: a driver shaft coupled to the accessory drive, a driven shaft coupled to the power turbine, and a clutch mechanism with pressure plate and friction disc. This segmentation allows independent control of each shaft's rotational speed, enabling optimized engine start sequences while maintaining manageable system complexity through modular design.
Solution Approach 2:
The clutch mechanism introduces dynamic control to the previously static coupling system. The pressure plate can move axially to engage or disengage the friction disc, allowing the system to transition between coupled and uncoupled states. This dynamic capability enables optimized engine starting by synchronizing shaft speeds before engagement, improving combustion pressure ratio while maintaining simple overall system architecture.
2Stability of the object's composition
If shafts are coupled during engine start, then synchronized rotation is achieved, but mechanical wear increases
Solution Approach 1:
The system performs preliminary speed synchronization before engaging the clutch. The accessory drive shaft is accelerated to match the power turbine shaft speed prior to coupling, as indicated by the sequential engagement design. This preliminary action ensures that when the friction disc engages the pressure plate, the relative velocity is minimized, reducing mechanical wear while achieving the necessary synchronized rotation for stable engine operation.
Solution Approach 2:
The friction disc acts as an intermediary element between the driver shaft and driven shaft during engagement. This intermediary allows for gradual torque transfer and speed synchronization, reducing shock loads and mechanical wear compared to direct coupling. The clutch mechanism mediates the connection, enabling smooth engagement that protects the shafts and connected components from excessive wear.
3Productivity
If shafts are decoupled after start, then independent operation is enabled, but combustion efficiency decreases
Solution Approach 1:
The clutch mechanism enables dynamic transition between coupled and uncoupled states based on engine operating conditions. During start-up, the shafts remain coupled to ensure synchronized rotation and optimal combustion efficiency. After the engine reaches a predetermined speed threshold indicating stable operation, the clutch disengages to allow independent rotation of the power turbine shaft, enabling power extraction without compromising combustion efficiency during the critical start phase.
Solution Approach 2:
The coupling state changes periodically based on engine operation phase: coupled during start-up for efficiency, uncoupled during power extraction for independent operation. This periodic action optimizes the balance between combustion efficiency and power output capability, allowing the system to achieve both goals at different operational stages rather than compromising either permanently.
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 solution enables efficient engine start by ensuring synchronized rotation of spools during startup and independent operation post-startup, improving the engine's combustion efficiency and reducing wear on components.
Implementation Method 1
a first friction surface rotatingly coupled with the first gas turbine engine spool shaft and operable to move in response to the movable member of the actuator, a second friction surface rotatingly coupled with the second gas turbine engine spool shaft and operable to be selectively engaged with the first friction surface
Data Source
AI summary
A gas turbine engine is provided that includes a gearbox operable to selectively couple a relatively high pressure spool shaft to a relatively low pressure spool shaft. In one form the gearbox includes a cone clutch that engages a male member of the cone clutch to a female member of the cone clutch during an engine start of the gas turbine engine. A relatively high pressure of a working fluid can be used to bring the male member and the female member together. A spring can also be used to urge the male member and the female member apart when the working fluid is at a relatively low pressure.