Composite Turbine Engine Casing With Undulated Tows for Thermal Expansion
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Solution Overview
Problem
Composite casings for aircraft turbine engines face challenges in accommodating thermal expansion mismatch between metallic airfoils and composite casings, leading to increased radial clearance and reduced engine performance and fuel efficiency.
Innovation Solution
A composite casing design with circumferential reinforcing fiber tows undulated in the circumferential direction, allowing the matrix material to expand and match the thermal expansion of metallic airfoils, using materials with higher CTE to improve thermal compatibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If composite materials are used to manufacture turbine engine casings, then weight is reduced and fuel efficiency is improved, but thermal expansion mismatch with metallic airfoils causes increased radial clearance and reduced engine performance
Solution Approach 1:
The patent changes the thermal expansion parameter of the composite casing by selecting matrix materials with higher CTE (coefficient of thermal expansion) to match the thermal expansion characteristics of metallic airfoils, thereby reducing radial clearance variations during engine operation
Solution Approach 2:
The patent uses composite materials with specifically selected matrix materials (such as polymers with higher CTE) combined with reinforcement fibers to create a composite casing that exhibits thermal expansion properties compatible with metallic airfoils, resolving the thermal expansion mismatch problem
2Strength
If traditional composite materials with low CTE are used, then structural strength is maintained, but thermal expansion mismatch increases radial clearance reducing engine performance
Solution Approach 1:
The patent modifies the thermal expansion parameter by selecting matrix materials with higher CTE values while maintaining the structural integrity through proper composite design, achieving both strength requirements and thermal compatibility
Solution Approach 2:
The patent applies different material properties in different directions within the composite structure, using fiber orientation and matrix material selection to provide both structural strength in critical directions and appropriate thermal expansion in radial directions
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
The design maintains a tight clearance between airfoils and casings, enhancing engine performance and fuel efficiency by aligning thermal expansion rates.
Implementation Method 1
Each circumferential reinforcing fiber tow of the plurality of circumferential reinforcing fiber tows extends in the circumferential direction and has a plurality of undulations in the circumferential direction to allow the matrix material of the composite section to expand circumferentially
Data Source
AI summary
A casing for a turbine engine including a composite section. The composite section has (i) an arcuate shape or an annular shape and (ii) a circumferential direction. The composite section includes a matrix and a plurality of circumferential reinforcing fiber tows embedded in the matrix. Each circumferential reinforcing fiber tow of the plurality of circumferential reinforcing fiber tows extends in the circumferential direction and has a plurality of undulations in the circumferential direction to allow the matrix material of the composite section to expand circumferentially.