Gas Turbine Combustor Wall Overlapping Portion Tolerance Compensation
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Solution Overview
Problem
Gas turbine combustor seals face challenges in maintaining accuracy and sealing integrity due to manufacturing tolerances, which can lead to interference with cooling airflow and fuel nozzle openings as the size of overlapping portions increases, affecting the assembly of interengaged components.
Innovation Solution
The design incorporates slotted or oversized openings in the exterior overlapping portions of the combustor walls to align with smaller openings in the interior portions, accommodating manufacturing and alignment tolerances while maintaining sealing surface integrity and structural rigidity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the size of overlapping portions is increased to improve sealing reliability, then the likelihood of maintaining the seal increases, but interference with openings for cooling airflow and fuel nozzles increases
Solution Approach 1:
The patent applies local quality by making the openings in the exterior overlapping portion larger only in the specific local area where tolerance accumulation occurs, while maintaining standard opening sizes in other areas. This localized enlargement of openings compensates for potential misalignment due to manufacturing tolerances without increasing the overall size of overlapping portions, thus avoiding interference with cooling airflow and fuel nozzles.
2Manufacturing precision
If manufacturing tolerances are tightened to improve assembly accuracy, then component alignment improves, but manufacturing complexity and cost increase
Solution Approach 1:
The patent changes the parameter of opening size in the exterior overlapping portion, making it larger than standard openings. This parameter change compensates for manufacturing tolerances and cumulative dimensional variations, allowing standard manufacturing tolerances to be maintained while achieving proper alignment and assembly accuracy without increasing manufacturing complexity.
3Adaptability or versatility
If the number of interengaged parts is increased to improve combustor assembly, then assembly flexibility improves, but cumulative lack of accuracy from manufacturing tolerances increases
Solution Approach 1:
The patent applies beforehand cushioning by designing larger openings in the exterior overlapping portion in advance, which compensates for cumulative dimensional inaccuracies that will result from multiple interengaged parts. This pre-built tolerance compensation allows the combustor assembly to accommodate cumulative errors from multiple components without requiring tighter manufacturing tolerances on each individual part.
Data Source
AI summary
A combustor for a gas turbine engine having an inner combustor wall and an outer combustor wall with a number of heat shields mounted internally thereto with fasteners. Each combustor wall has an end wall defining a combustor dome with a number of: fuel nozzle openings; impingement air openings; and heat shield fastener openings. Each of the end walls has an overlapping portion with mutually engaging sealing surfaces with the openings within the overlapping portions being aligned in overlapping pairs, where an exterior overlapping portion has at least one of the aligned openings of one overlapping pair being of larger dimension than the aligned opening in an interior overlapping portion.