Gas Turbine Gear Assembly Mount Stiffness for Load Sharing
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Solution Overview
Problem
Geared gas turbine engines face issues with uneven load sharing between components, leading to overload conditions and clearance closures, which can result in gear assembly and engine failure, and necessitate stiffer, heavier structures that reduce efficiency.
Innovation Solution
The implementation of a mount arrangement with distinct stiffness levels for different components, where the first mount member has a stiffness K1 less than or equal to 10% of the third mount member's stiffness K3, and the second mount member's stiffness K2 is between 0.5 and 2.0 times that of K3, allowing the first rotatable component to float independently while constraining the second rotatable and torque transfer components to the same frame, thereby mitigating uneven load sharing and clearance closures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If stiffer structures are used to prevent clearance closure between gear assembly components, then reliability is improved, but weight increases and engine efficiency decreases
Solution Approach 1:
The patent applies parameter changes by varying the stiffness values of different mount members (K1, K2, K3) to achieve optimal performance. Specifically, K1 is set to be less than or equal to 10% of K3, and K2/K3 ratio is between 0.5 and 2.0, creating a differentiated stiffness distribution that prevents clearance closure without requiring uniformly stiff structures
Solution Approach 2:
The patent implements local quality by assigning different stiffness characteristics to different mount members based on their specific functions. The first mount member (K1) has low stiffness to accommodate thermal expansion, the second mount member (K2) has moderate stiffness for load distribution, and the third mount member (K3) has high stiffness for structural support, optimizing each location's properties
2Reliability
If stiffer structures are used to prevent clearance closure, then reliability is improved, but engine efficiency deteriorates
Solution Approach 1:
The patent uses parameter changes by establishing specific stiffness ratios (K1 ≤ 0.1K3 and 0.5 ≤ K2/K3 ≤ 2.0) to achieve the optimal balance between reliability and efficiency. This differentiated parameter assignment allows the system to maintain reliability through targeted stiffness distribution rather than uniform stiffening, reducing unnecessary energy consumption
3Stability of the object's composition
If rigid mounting is used for all gear assembly components, then load sharing is improved, but adaptability to thermal expansion deteriorates
Solution Approach 1:
The patent applies local quality by assigning different stiffness characteristics to different mount members based on their specific functions. The first mount member (K1) has low stiffness to accommodate thermal expansion, the second mount member (K2) has moderate stiffness for load distribution, and the third mount member (K3) has high stiffness for structural support, optimizing each location's properties
Solution Approach 2:
The patent implements dynamics by creating a flexible mounting system that can adapt to changing operating conditions. The differentiated stiffness values allow the mount arrangement to dynamically adjust to thermal expansion and contraction while maintaining stable load sharing, rather than using a fixed rigid mounting for all components
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 reduces the risk of overload conditions, minimizes clearance closures, and enables larger loads or thrusts to be handled by smaller gear assemblies, improving power density and engine efficiency.
Implementation Method 1
a first mount member defining a stiffness K1; a second frame including a second mount member defining a stiffness K2 and a third mount member defining a stiffness K3... The stiffness K1 is less than or equal to 10% of the stiffness K3... a ratio of stiffness K2/K3 is greater than approximately 0.5 and less than approximately 2.0
Data Source
AI summary
A gas turbine engine including a first frame including a first mount member defining a stiffness K1; a second frame including a second mount member defining a stiffness K2 and a third mount member defining a stiffness K3; and a gear assembly. The gear assembly includes a first rotatable component, a second rotatable component, and a torque transfer component. The first mount member is coupled to the first rotatable component. The second mount member is coupled to the second rotatable component. The third mount member is coupled to the torque transfer component. The stiffness K1 is less than or equal to 10% of the stiffness K3.