Diffuser Seal Aft Movement Containment Geared Turbofan
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
During a fan blade-out event in geared turbofan engines, the potential for shaft failure poses a risk of damage to the high pressure turbine due to uncontrolled movement and debris entry, which can lead to catastrophic consequences such as puncture of engine components or detachment from the aircraft.
Innovation Solution
A diffuser seal assembly is implemented, comprising a flow guide carrier coupled to a static seal and a fairing/hub support, which engages the aft surface of a fairing to limit movement of the rear hub and fairing in the aft direction, allowing air flow through the seals and directing cooling air to the turbine while preventing debris from entering the high pressure turbine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the fan is allowed to rotate freely during a fan blade-out event, then aerodynamic drag is reduced and the engine can continue to windmill, but uncontrolled movement and debris may damage the high pressure turbine
Solution Approach 1:
The diffuser seal assembly acts as an intermediary protective barrier between the rotating fan assembly and the high pressure turbine. The seal includes a containment structure with a seal element that interfaces with the fan assembly, allowing controlled movement while blocking debris and uncontrolled particles from entering the turbine compartment, thus resolving the contradiction between allowing rotation and preventing damage
Solution Approach 2:
The diffuser seal assembly is pre-installed in the high pressure compressor outlet position to provide beforehand protection. The seal structure is designed to engage with the fan assembly before any debris can reach the turbine, creating a protective cushion that absorbs and redirects harmful forces during a fan blade-out event
2Reliability
If a seal is installed to prevent debris entry into the high pressure turbine, then turbine protection is improved, but air flow to the turbine may be restricted
Solution Approach 1:
The seal element is designed with localized sealing functionality at specific interfaces where debris generation is most likely, rather than creating a complete barrier. The seal provides localized protection at the critical interface between the fan assembly and high pressure compressor outlet, allowing air flow through other pathways while maintaining turbine protection
3Stability of the object's composition
If the rear hub and fairing are allowed to move aft during a fan blade-out event, then structural flexibility is maintained, but uncontrolled movement increases the risk of debris penetration
Solution Approach 1:
The diffuser seal assembly incorporates a dynamic seal element that can adapt its position and deformation based on the operational conditions. During normal operation, the seal maintains structural integrity, but during a fan blade-out event, the seal element can deform and move to accommodate the dynamic forces while still providing protection, thus maintaining structural flexibility while preventing debris penetration
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 diffuser seal assembly effectively prevents damage to the high pressure turbine by containing aftward movement of the rotor, reducing wear on bearings, and providing structural integrity to the rear hub, thereby minimizing the risk of debris penetration and maintaining engine stability during a fan blade-out event.
Implementation Method 1
The static seal engages the rotary seal and permits air flow through the static and rotary seals in an aft direction
Implementation Method 2
The fairing/hub support extends forward from the flow guide support and engages an aft surface of the fairing thereby limiting movement of the rear hub and fairing in the aft direction
Implementation Method 3
The flow guide carrier supports the fairing in a spaced-apart position with respect to the rear hub so that air flowing through the static and rotary seals passes between a forward surface of the fairing and the rear hub
Data Source
AI summary
A diffuser seal for an aft end of a high pressure compressor of a gas turbine engine is disclosed. The diffuser seal includes a flow guide carrier coupled to the diffuser case. The flow guide carrier is also coupled to a static seal. The static seal engages a rotary seal and permits air flow through the static and rotary seals in the aft direction. The flow guide carrier is also coupled to a fairing and a fairing/hub support. The flow guide carrier supports the fairing in a spaced-apart position with respect to the rear hub so that air flowing through the static and rotary seals passes between a forward surface of the fairing and the rear hub. The fairing/hub support extends forward from the flow guide support and engages an aft surface of the fairing thereby limiting movement of the rear hub and fairing in the aft direction. This design helps to prevent parts or debris from piercing the rear hub and entering the high pressure turbine in the even of a fan blade-out or fan blade-off event.