SOFC Glow Plug Sealing Structure for Heat Leak and Crack Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
High temperature solid oxide fuel cell (SOFC) systems face issues with heat leaks and temperature variations due to gaps in the hot box and instrumentation feed-through holes, leading to stress and potential damage to components, and the difference in thermal expansion coefficients between housing and heating elements can cause micro-crack formation and reduce the longevity of glow plugs.
Innovation Solution
A method of sealing the glow plug in the SOFC system using a sealing element with an annular base and a tubular collar, where the collar is attached to the heating element and the base is attached to the housing, along with the use of pourable insulation materials to maintain stable temperatures and reduce thermal variations, and the use of compatible materials with matched coefficients of thermal expansion to minimize stress on the heating elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a glow plug is installed in the SOFC system, then heating function is provided, but heat leaks and temperature variations occur due to gaps in the hot box and instrumentation feed-through holes
Solution Approach 1:
A sealing element is introduced as an intermediary component between the heating element and the hot box to eliminate gaps and prevent heat leaks. The sealing element fills the feed-through hole and creates a fluid-tight and thermally efficient connection, preventing harmful heat loss while maintaining the heating function.
Solution Approach 2:
The sealing element is formed from a composite material comprising a metal matrix and ceramic particles distributed throughout the matrix. This composite structure provides both mechanical strength and thermal insulation properties, reducing heat leaks while maintaining structural integrity at high temperatures.
2Strength
If housing and heating element materials are used, then structural components are provided, but micro-crack formation occurs due to difference in thermal expansion coefficients
Solution Approach 1:
The thermal expansion coefficient of the heating element is modified by adjusting the ceramic particle content and type in the composite material. By changing this physical parameter, the thermal expansion characteristics are matched to the housing material, eliminating differential thermal expansion stresses that cause micro-cracks and improving reliability.
Solution Approach 2:
The heating element uses a composite material with ceramic particles distributed throughout the metal matrix, creating local variations in thermal expansion properties. This local quality adjustment allows the material to better accommodate thermal stresses at the interface with the housing, preventing crack formation.
3Reliability
If a sealing element with collar and base is used, then fluid-tight connection is achieved, but device complexity increases
Solution Approach 1:
The sealing element combines multiple functions into a single integrated component: the tubular collar provides sealing at the heating element interface, the annular base seals against the hot box, and the connecting portion joins these features. This merging eliminates the need for separate sealing components, reducing assembly complexity while maintaining fluid-tight 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 effectively reduces the risk of glow plug failure, improves thermal and electrical efficiency, and extends the operational reliability and longevity of the SOFC system by maintaining stable temperatures and minimizing thermal stress.
Implementation Method 1
a heating element extending from a first end of the housing
Implementation Method 2
pours a high temperature resistant insulating material into a space between the heating element and the hot box housing
Implementation Method 3
use of pourable insulation materials to maintain stable temperatures and reduce thermal variations
Data Source
AI summary
A method of sealing a glow plug of a fuel cell system, the glow plug including a housing and a heating element extending from a first end of the housing. The method includes inserting the heating element into a sealing element having an annular base and a tubular collar extending from the base and forming a fluid-tight connection between the glow plug and the fuel cell system by attaching the collar to the heating element and by attaching the base to the first end of the housing.