Active Clearance Control Spring Member for Fan Rotor Casing
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Solution Overview
Problem
Propulsion systems face efficiency and performance losses due to large clearances between fan blades and containment casings, which are implemented to prevent hard contact but result in undesired contact and increased fuel consumption.
Innovation Solution
A containment casing with an outer and inner layer material and a spring member between them, where the spring member has a higher coefficient of thermal expansion than the outer layer, allowing for modulated clearance control through temperature adjustments and fluid flow management to optimize fan rotor clearance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large clearance is defined between fan blade tip and containment casing, then undesired contact is mitigated, but efficiency and performance are reduced due to increased fuel consumption
Solution Approach 1:
The containment casing transitions from a static structure to a dynamic one by incorporating a spring member that enables radial movement. The spring member allows the casing to expand and contract radially in response to thermal changes and operational conditions, dynamically adjusting the clearance between the fan blade tip and casing to optimize both contact mitigation and efficiency
Solution Approach 2:
The invention utilizes thermal expansion parameter changes by incorporating materials with different coefficients of thermal expansion (CTE). The spring member has a higher CTE than the outer layer material, causing it to expand more with temperature increase, which drives radial expansion of the casing to maintain optimal clearance under varying thermal conditions
2Reliability
If a relatively large clearance is defined to avoid hard contact, then fan rotor reliability is improved, but propulsion system performance deteriorates
Solution Approach 1:
The spring member provides dynamic adjustment capability that allows the casing to adapt clearance based on real-time operational conditions, ensuring reliable fan rotor operation while maintaining optimal propulsion efficiency through active clearance management
Solution Approach 2:
The system incorporates thermal feedback through the spring member's CTE-driven response to temperature changes. As the engine operates and temperatures rise, the spring member expands, automatically adjusting the casing position to maintain optimal clearance, creating a self-regulating system that balances reliability and performance
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 system effectively mitigates undesired contact while improving propulsion system efficiency and performance by dynamically adjusting clearance based on thermal expansion and fluid temperature, maintaining optimal operation across various conditions.
Implementation Method 1
The spring member defines a second CTE greater than the first CTE
Data Source
AI summary
A propulsion system including a casing surrounding a fan rotor assembly is provided. An example casing includes an outer layer material, an inner layer material including first openings extended partially through the inner layer material along a radial direction of a first side of the inner layer material, and second openings extended partially through the inner layer material along the radial direction of a second side of the inner layer material opposite the first side, and a spring member coupled to the outer layer material and the inner layer material.