Turbine Trunnion Drop-Launching Extension Oil Backflow
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Solution Overview
Problem
High-pressure turbojet engines produce fumes due to oil accumulation in hot areas caused by backflow, particularly at low speeds, where the centrifugal effect is insufficient to prevent oil penetration between the trunnion and seal support.
Innovation Solution
A trunnion with a drop-launching extension and annular recess is positioned between the low-pressure turbine shaft and the seal support, projecting oil towards a flared portion to prevent backflow and oil penetration, utilizing centrifugal force to guide oil away from the interface and into the seal support, thereby reducing fume production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the turbojet engine operates at low speed, then the centrifugal effect is insufficient, but oil backflow and accumulation in hot areas increases
Solution Approach 1:
The drop-launching extension is positioned and shaped to preemptively intercept and redirect oil before it can penetrate into the seal support and accumulate in hot areas. This preliminary action prevents the harmful effect before it occurs, regardless of engine speed
Solution Approach 2:
The drop-launching extension acts as an intermediary element between the trunnion and the seal support, intercepting oil and redirecting it toward the flared portion before it can cause harmful accumulation in hot areas
2Speed
If the centrifugal effect is weak at low speed, then oil circulation is insufficient, but oil penetration between trunnion and seal support increases
Solution Approach 1:
The recess and drop-launching extension create preliminary barriers that stop oil penetration before it occurs, making the sealing effective even when centrifugal force is weak at low speeds
Solution Approach 2:
The recess is positioned at a specific location on the trunnion surface to create a localized barrier against oil penetration, while the drop-launching extension provides localized redirection of oil flow toward the flared portion
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 limits oil backflow and fume formation by using centrifugal force to direct oil away from the interface, enhancing lubrication circulation and reducing unwanted emissions during engine startup and operation.
Implementation Method 1
when the trunnion is driven in rotation around the low-pressure turbine shaft, oil tending to penetrate between the trunnion and the seal support is projected by centrifugal effect from the drop-launching extension towards the flared portion of the inner surface of the seal support
Implementation Method 2
the recess stopping penetration of oil between the trunnion and the seal support and causing detachment of the oil towards the inner surface of the seal support by centrifugal effect
Implementation Method 3
the drop-launching extension has an outer surface tilted relative to an axis of rotation of the trunnion, tending to guide the oil towards the recess by centrifugal effect when the trunnion is driven in rotation
Data Source
AI summary
The invention relates to a trunnion (23) for a high-pressure turbine (11), to be arranged between a shaft of a low-pressure turbine (9) and an inner surface (34) of a seal mounting (26) of the low-pressure turbine (8), the trunnion (23) being characterized in that it includes a drop-launching extension (32) arranged such as to extend opposite a flared portion (33) of the inner surface (34) of the seal mounting (26), such that when the trunnion (23) is rotated about the shaft of the low-pressure turbine (9), oil (H2), which tends to penetrate between the trunnion (23) and the seal mounting (26), is thrown by centrifugal effect from the drop-launching extension (32) toward the flared portion (33) of the inner surface (34) of the seal mounting (26).