Turbine Engine Nut Assembly with Deformable Thermal Connector
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Solution Overview
Problem
The use of ceramic matrix composite materials in turbine engine exhaust cones, while improving efficiency and reducing mass, results in mechanical stresses due to thermal expansion mismatch between metal retainer devices and structural elements, potentially causing damage.
Innovation Solution
A nut device with a retainer connected by a deformable connecting element compensates for the greater thermal expansion of the retainer, maintaining alignment and reducing mechanical stresses by allowing limited movement of the nuts within recesses, and using a holding member to prevent rotation during assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If ceramic matrix composite materials are used for structural elements in the exhaust cone, then engine efficiency is improved and mass is reduced, but mechanical stresses are induced due to thermal expansion mismatch with metal retainer devices
Solution Approach 1:
The patent changes the physical state and properties of the connecting element by making it deformable rather than rigid. This allows the connecting element to change its dimensional parameters in response to thermal expansion differences, accommodating the mismatch between metal retainer and ceramic structural elements without inducing damaging mechanical stresses
Solution Approach 2:
The patent introduces dynamic adaptability by using a deformable connecting element that can adjust its configuration in response to thermal conditions. The connecting element transitions from a rigid constraint to a flexible connector that adapts to thermal expansion variations, maintaining structural integrity under varying thermal loads
2Manufacturing precision
If a rigid retainer device is used to secure nuts, then assembly precision is maintained, but thermal expansion mismatch causes mechanical stresses and potential damage
Solution Approach 1:
The patent transforms the rigid retainer into a dynamic system where the connecting element can deform to accommodate thermal expansion. This maintains alignment precision during assembly while providing reliability during operation by allowing thermal movement without causing damage
Solution Approach 2:
The connecting element's physical parameters (shape, dimensions) are designed to change in response to thermal conditions. The deformable nature allows the retainer to maintain functional precision while adapting to thermal expansion, preventing stress-induced damage
3Ease of manufacture
If floating nut devices are used to connect exhaust cone components, then assembly is enabled without radial access, but thermal expansion of metal retainer induces stresses in ceramic structural elements
Solution Approach 1:
The patent modifies the physical parameters of the connecting element to be deformable, allowing it to change its dimensional characteristics in response to thermal expansion. This maintains the ease of assembly advantage while eliminating the thermal stress problem by accommodating expansion differences
Solution Approach 2:
The retainer device is made dynamically adaptive through the deformable connecting element, which can adjust its configuration during thermal cycling. This maintains manufacturing ease while preventing stress accumulation that would occur with rigid connections
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 solution maintains structural integrity and reduces the risk of damage to the exhaust cone components by accommodating thermal expansion, enhancing the durability and efficiency of the turbine engine.
Implementation Method 1
the coefficient of thermal expansion of a ceramic matrix composite is significantly lower than the coefficient of thermal expansion of a metal. Therefore, when such a floating nut device is used at exhaust cone 40, as the temperature rises during operation of the turbine engine, the retainer of the floating nut device has greater thermal expansion than that of the structural element
Implementation Method 2
The connecting element is deformable, in whole or in part, to compensate for the greater thermal expansion of the retainer than the thermal expansion of the first structural element
Data Source
AI summary
An assembly for a turbine engine having a longitudinal axis includes a first structural element and a nut device, the first structural element having a first hole and a second hole, and the nut device having a retainer fixed to an inner face of the first structural element., the retainer comprising at least a first recess and a second recess connected to one another by a connecting element, the first recess and the second recess each retaining a nut respectively aligned with the first hole and the second hole which are formed through the first structural element, the connecting element being, in whole or in part, adapted to compensate for a greater thermal expansion of the retainer than the thermal expansion of the first structural element.