Turbine Engine Tip-Clearance Control With a Thrust Bearing
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Solution Overview
Problem
Existing tip clearance control systems in turbine engines struggle to maintain optimal clearance between rotor blades and shrouds, leading to inefficiencies due to thermal expansion and contraction, which can cause either air leakage or blade rub issues.
Innovation Solution
A tip clearance control system utilizing a thrust bearing that synchronizes the axial movement of rotor blades with the movement of the shroud, coupled with a flex coupling to maintain consistent clearance through thermal expansion and contraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid connection is used between the rotor assembly and shroud, then structural stability is improved, but thermal expansion and contraction cause clearance variations leading to air leakage or blade rub
Solution Approach 1:
The thrust bearing enables the shroud to move axially in response to thermal expansion and contraction of the rotor assembly, transforming a rigid static connection into a dynamic adaptive system that maintains optimal clearance under varying thermal conditions
Solution Approach 2:
The system allows the axial position parameter of the shroud to change in response to temperature variations, enabling the clearance between rotor blades and shroud to be maintained within optimal limits despite thermal effects
2Manufacturing precision
If the shroud is fixed axially, then manufacturing precision is improved, but thermal expansion causes clearance variations leading to air leakage or blade rub
Solution Approach 1:
The thrust bearing provides a controlled degree of freedom for axial movement, allowing the shroud to adapt its position dynamically while maintaining precise alignment, thus resolving the conflict between fixed positioning and thermal adaptation
3Reliability
If the rotor assembly is allowed to move axially freely, then thermal expansion is accommodated, but structural stability deteriorates
Solution Approach 1:
The thrust bearing acts as a constrained support that counteracts uncontrolled axial movement while permitting controlled displacement for clearance maintenance, providing stability while accommodating thermal effects
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 maintains optimal clearance between rotor blades and shrouds, minimizing air leakage and blade rub risks, thereby enhancing compressor efficiency and reducing operational inefficiencies.
Implementation Method 1
maintain a select clearance between blade tips of a rotor and an adjacent shroud... thermal expansion and contraction
Implementation Method 2
maintain a select clearance between blade tips of a rotor and an adjacent shroud... thermal expansion and contraction
Data Source
AI summary
An assembly is provided for an aircraft powerplant. This assembly includes a rotating assembly, a first structure, a second structure and a thrust bearing. The rotating assembly includes a first bladed rotor and a second bladed rotor. The first bladed rotor includes a plurality of first rotor blades. The second bladed rotor includes a plurality of second rotor blades. The first structure is configured as or otherwise includes a first shroud. The first shroud circumscribes the first bladed rotor. The first shroud is adjacent first tips of the first rotor blades. The second structure is configured as or otherwise includes a second shroud. The second shroud circumscribes the second bladed rotor. The second shroud is adjacent second tips of the second rotor blades. The second shroud is configured to move along an axis relative to the first shroud. The thrust bearing couples the rotating assembly to the second structure.