Coolable Borescope Boss with Internal Air Spraying
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional borescope plugs in aircraft gas turbine engines experience premature deterioration due to overheating from trapped hot air, leading to high maintenance costs, as they are made from less capable materials and do not effectively cool the plug tip and port.
Innovation Solution
A coolable borescope boss with integrated cooling passages that spray cooling air into a boss hole, providing thermal management through conical and cylindrical designs, and cooling inlets/outlets to reduce thermal degradation of the plug tip and port.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional borescope plugs are used without cooling, then the structure is simple and cost-effective, but the plug tip and port experience premature deterioration due to overheating from trapped hot air
Solution Approach 1:
The patent applies pneumatic cooling by introducing cooling air through passages into the cavity behind the plug tip. The cooling air flow removes trapped hot air and reduces metal temperatures at the port walls and plug tip, thereby preventing premature deterioration and extending service life without significantly complicating the structure
Solution Approach 2:
The patent introduces cooling air as an intermediary substance between the hot trapped air and the metal surfaces. The cooling air acts as a thermal mediator that absorbs heat from the port walls and plug tip, reducing thermal degradation while maintaining the structural simplicity of the conventional plug design
2Reliability
If cooling passages are added to the borescope boss, then thermal degradation is reduced and service life is extended, but the device complexity and manufacturing cost increase
Solution Approach 1:
The cooling system is segmented into multiple independent cooling passages distributed within the boss structure. This segmentation allows the cooling function to be distributed throughout the structure, providing effective thermal management while maintaining manufacturing feasibility and avoiding excessive complexity in any single region of the boss
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 coolable borescope boss effectively reduces thermal degradation and maintains a good seal, extending the lifespan of the borescope plug and port by efficiently cooling the tip and surrounding areas, thus lowering maintenance costs.
Implementation Method 1
cooling passages extending through the boss and oriented for spraying cooling air into the boss hole
Implementation Method 2
cooling passages are oriented for spraying cooling air into the boss hole
Data Source
AI summary
A coolable borescope boss includes cooling passages extending through the boss and oriented for spraying cooling air into a hole extending through the boss. Centerlines of the cooling passages may intersect the a hole axis of the hole. The cooling passages may be cylindrical or open slots disposed through the boss. The boss may be on an arcuate gas turbine engine shroud segment circumscribed about an axial centerline axis. The segment may be part of an annular segmented turbine shroud having cylindrical shroud first and second sections and a conical shroud midsection therebetween and the segment having cylindrical segment first and second sections and a conical segment midsection therebetween. A hole exit of the hole being flush with the conical segment midsection. A borescope plug tip having a spherical tip chamfer may be used to seal against a conical boss chamfer of the boss.