Composite Turbine Blade Profile Optimization for Stress Reduction
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Solution Overview
Problem
Turbine engine blades made of metal experience mechanical strength degradation at high temperatures, leading to increased mechanical stresses in hot zones, while composite material blades have improved high-temperature strength but suffer from mechanical stresses at the root during rotation.
Innovation Solution
A method to optimize the profile of composite material blades by calculating and applying shift values to the centers of gravity of blade sections to balance centrifugal and aerodynamic forces, reducing mechanical stresses and extending blade lifetime, allowing for the use of weaker materials at the root.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If metal blades are used in turbine engines, then they can withstand high temperatures, but their mechanical strength becomes greatly degraded at high temperatures leading to increased mechanical stresses in hot zones
Solution Approach 1:
The patent applies composite materials (specifically ceramic matrix composites - CMCs) to replace metal blades in high-temperature zones of turbine engines. CMC blades maintain mechanical strength at high temperatures where metal blades would degrade, thereby resolving the contradiction between temperature resistance and mechanical strength.
2Strength
If composite material blades are used, then mechanical strength at high temperatures is improved, but high mechanical stresses appear at the root of the blade during rotation
Solution Approach 1:
The patent applies local quality by optimizing the geometrical profile of different parts of the blade differently. The airfoil section (hot zone) uses a profile optimized for high-temperature strength, while the root section (cold zone) uses a profile optimized to reduce mechanical stresses during rotation. This localized optimization resolves the contradiction between high-temperature strength and root stress reduction.
Solution Approach 2:
The patent changes the geometrical parameters (profile shape, thickness distribution) of the blade in different sections to optimize performance. By varying the profile parameters along the blade length, the design achieves both high-temperature strength in the airfoil and reduced root stresses, resolving the contradiction.
3Duration of action of moving object
If the profile of the blade is optimized to reduce mechanical stresses, then the lifetime of the blade increases, but the geometrical profile becomes more complex
Solution Approach 1:
The patent segments the blade into distinct sections (airfoil and root) and applies different profile optimizations to each segment. This segmentation allows the complex stress-reduction geometry to be applied only where needed (at the root), while keeping the airfoil section simpler, thereby resolving the contradiction between extended lifetime and overall complexity.
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 method effectively reduces mechanical stresses on composite material blades, increasing their lifetime and enabling the use of less strong materials at the root, while maintaining aerodynamic performance and optimizing the blade's mass and size.
Implementation Method 1
calculating the centrifugal force to which the slice is subjected
Data Source
AI summary
A method optimizing a composite material blade profile for a rotor wheel of a turbine engine, and a blade including a tang compensated by the method. The method includes: compensating a blade airfoil by subdividing the airfoil into slices, and for each airfoil slice and a predetermined rotation speed of a disk of the wheel, calculating centrifugal force applied to the slice, calculating an aerodynamic force moment acting on a bottom section of the slice, and calculating shift values to be applied to a center of gravity of the slice to cancel the aerodynamic force moment; and compensating the blade tang by calculating centrifugal force applied to a blade portion situated beyond the airfoil neck, calculating an aerodynamic force moment acting on a bottom section of the blade tang, and calculating shift values to be applied to a center of gravity of the blade tang to cancel the aerodynamic force moment.