Gas Turbine Seal Structure Preventing Coating Damage
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Solution Overview
Problem
In gas turbines, differences in thermal elongation due to temperature changes cause variations in clearance between components, potentially leading to contact and damage to heat-resistant coatings during operation.
Innovation Solution
A seal structure is implemented with a contact part that restricts the relative movement of adjacent members by contacting surfaces without heat-resistant coatings, preventing direct contact between coated surfaces and maintaining a clearance to protect the coatings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the clearance between adjacent members is reduced due to thermal elongation differences, then the members may come in contact with each other, but this causes damage to the heat-resistant coating
Solution Approach 1:
A seal member is introduced as an intermediary component between the combustor and turbine vane. This seal member includes a contact part that makes contact with the turbine vane before the heat-resistant coated surfaces can contact each other, thereby preventing coating damage while accommodating thermal expansion differences
Solution Approach 2:
The contact part of the seal member is positioned to make preliminary contact with the turbine vane at a location away from the heat-resistant coating. This preliminary contact action prevents the coated surfaces from approaching each other closely enough to cause damage, addressing the thermal expansion issue before it can harm the coating
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 seal structure effectively prevents contact between coated surfaces, thereby protecting the heat-resistant coatings and ensuring the longevity of gas turbine components.
Implementation Method 1
differences in thermal elongation among the members composing the gas turbine result in differences in thermal elongation. Accordingly, clearances between the members vary with the operation state of the gas turbine
Data Source
AI summary
A seal structure includes: a first member and a second member facing a combustion gas flow passage; a third member on an outer side of the combustion gas flow passage; a heat-resistant coating on at least one of a first end face and a second end face, both of the first end face and the second end face being closer to the combustion gas flow passage; and a contact part in each of the first end face and the second end face, further on the outer side of the combustion gas flow passage than the heat-resistant coating. The contact part is configured to restrict relative movement of the first member and the second member by directly or indirectly coming into contact with the first member and the second member in a state where a clearance is left between the heat-resistant coating and the end face facing the heat-resistant coating.