Combustor Washer Airflow Structure for Cooling Stud Standoffs
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Solution Overview
Problem
Gas turbine engine combustor components, particularly studs and standoffs, experience reduced service life due to high thermal stresses from mechanical fastener arrangements, which are ineffective in managing thermal loads.
Innovation Solution
A combustor design incorporating a washer with radially inwardly extending arms that defines a cooling airflow passage to direct cooling airflow through the shell opening, impinging on the stud or standoff, thereby reducing thermal stress and extending the service life of these components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mechanical fastener arrangements (studs and nuts) are used to secure combustor panels to the combustor shell, then the combustor panels are firmly attached and thermally protect the combustor shell, but the studs are subjected to high temperatures which reduces their service life
Solution Approach 1:
A washer is introduced as an intermediary component between the nut and the combustor shell. This washer includes cooling airflow passages that allow cooling air to flow through and impinge on the stud, thereby reducing the thermal load on the stud while maintaining the mechanical fastening function
Solution Approach 2:
The washer incorporates cooling airflow passages that utilize pneumatic flow of cooling air to remove heat from the stud. The cooling air is directed through the washer and impinges on the stud surface, creating a cooling effect that reduces thermal stress and extends service life
2Reliability
If the studs are exposed to high temperatures from combustion gases, then the mechanical fastening function is maintained, but the thermal stress reduces the service life of the combustor components
Solution Approach 1:
The washer serves as a mediator that protects the stud from direct exposure to high temperatures. The cooling airflow passages in the washer allow cooling air to flow between the nut and combustor shell, creating a thermal barrier that reduces heat transfer to the stud
Solution Approach 2:
The cooling airflow passages change the thermal parameters of the stud by introducing cooling air that reduces the temperature of the stud surface. This parameter change (temperature reduction) directly addresses the thermal stress issue while maintaining mechanical fastening reliability
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 cooling airflow passages within the washer structure effectively reduce the thermal stress on studs and standoffs, enhancing the service life and reliability of combustor components by efficiently managing thermal loads.
Implementation Method 1
The washer at least partially defines a cooling flow passage configured to direct a cooling airflow through the shell opening to impinge the cooling flow on at least one of the stud or the standoff
Implementation Method 2
a cooling airflow passage configured to direct a cooling airflow through the shell opening
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
A combustor (26) for a gas turbine engine (20) includes a combustor shell (58) having a shell opening (84) therethrough, a combustor panel (64) having a stud (80) attached thereto, the stud extending through the shell opening (84). The stud includes a standoff (94) to define an intermediate passage (74) between the combustor shell (58) and the combustor panel (64). A retainer (92) is attached to the stud (80). A washer (90) surrounds the stud (80) and is positioned between the retainer (92) and the combustor shell (58). The washer (90) at least partially defines a cooling flow passage (96) configured to direct a cooling airflow (70) through the shell opening to impinge the cooling flow on at least one of the stud (80) or the standoff (94).