Ceramic Combustor Can Attachment Using Compliant Clamp
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Solution Overview
Problem
Conventional combustor assemblies face challenges in maintaining a tight fit between ceramic and metal parts due to differences in thermal expansion coefficients, leading to thermal stress and ineffective joining methods.
Innovation Solution
A combustor assembly with a metal section and ceramic section secured using a clamp with radial deformation members, such as springs and tabs, to offset thermal expansion differences and maintain a clamping force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If ceramic materials are used in combustors to resist high temperatures, then temperature resistance is improved, but thermal stress and joining effectiveness deteriorate due to coefficient of thermal expansion mismatch with metal parts
Solution Approach 1:
The patent changes the physical state and mechanical properties of the attachment structure by introducing compliant deformation members (springs and tabs) that can elastically deform. This allows the attachment mechanism to adapt its parameters (clamping force, position) in response to thermal expansion differences, maintaining reliable connection between ceramic and metal sections across temperature variations.
Solution Approach 2:
The attachment structure transitions from a static rigid connection to a dynamic compliant system. The springs and tabs are designed to deform radially in response to thermal expansion, allowing the clamping structure to continuously adapt and maintain secure attachment despite dimensional changes in the ceramic and metal components during thermal cycling.
2Strength
If typical joining methods such as welding or bonding are used between ceramic and metal parts, then structural connection is achieved, but effectiveness deteriorates due to coefficient of thermal expansion difference
Solution Approach 1:
The patent introduces compliant deformation members (springs and tabs) as intermediary elements between the ceramic and metal sections. These intermediaries absorb the thermal expansion mismatch through elastic deformation, preventing stress concentration at the joint interface and maintaining reliable connection without requiring direct welding or bonding between dissimilar materials.
Solution Approach 2:
The attachment structure employs flexible compliant elements (spring washers and deformable tabs) that can elastically deform to accommodate dimensional changes. These flexible components act as compliant joints that maintain structural connection while absorbing thermal stress, replacing rigid welding or bonding methods that fail under thermal expansion mismatch.
3Force
If a rigid clamp is used to secure metal and ceramic sections, then initial clamping force is achieved, but clamping force is lost due to thermal expansion difference during operation
Solution Approach 1:
The clamp structure transitions from a static rigid connection to a dynamic compliant system. The springs and tabs are designed to deform radially in response to thermal expansion, allowing the clamping structure to continuously adapt and maintain secure attachment despite dimensional changes in the ceramic and metal components during thermal cycling.
Solution Approach 2:
The compliant deformation members are pre-installed in the attachment structure to provide cushioning against thermal expansion differences. These elements are positioned to deform in anticipation of thermal growth, absorbing dimensional changes before they can compromise the clamping force or create damaging stresses at the joint interface.
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 effectively maintains a secure attachment between thermally mismatched ceramic and metal sections over a wide temperature range, reducing thermal stress and undesirable emissions by using a combination of springs, tabs, and a gasket to provide a consistent clamping force.
Implementation Method 1
springs within the clamp deform in a radial direction to cooperatively offset the thermal expansion difference
Implementation Method 2
coefficient of thermal expansion of ceramics is typically much lower than that of metals, which may lead to thermal stress between parts made of ceramic and parts made of metal during operation
Implementation Method 3
Tabs on the metal section, a gasket between the metal section and the ceramic section, and springs within the clamp deform in a radial direction
Implementation Method 4
Tabs on the metal section, a gasket between the metal section and the ceramic section, and springs within the clamp deform in a radial direction
Data Source
AI summary
A combustor assembly includes a metal section having an axial slot that receives a ceramic section. A clamp is received about the axial slot to secure the metal section and ceramic section together. Tabs on the metal section, a gasket between the metal section and the ceramic section, and springs within the clamp deform an amount that is greater than a thermal expansion difference between the metal section and the ceramic section to maintain a clamping force of the clamp.