Movable Seal for Turbomachine Discharge Valve Airflow Clearance
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Solution Overview
Problem
Existing turbomachine discharge valves face a challenge in maintaining sealing between the primary and secondary air flow veins while avoiding obstruction of the aerodynamic air flow when the discharge door is in the open position.
Innovation Solution
A sealing device with a mobile tightness joint and a displacement system that moves the seal between a compressed position against the discharge door in the closed position and a retracted position when the door is open, ensuring uninterrupted aerodynamic flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is used to ensure sealing between the primary stream and secondary stream in the closed position of the wastegate, then sealing reliability is improved, but the seal extends into the airflow in the open position causing reduction in passage section of aerodynamic flow
Solution Approach 1:
The seal is made movable relative to the intermediate casing through a movement system that allows it to transition between a first position (bearing against the discharge door in closed position) and a second position (retracted from the air passage orifice in open position). This dynamic positioning resolves the contradiction by adapting the seal's location based on the valve state.
Solution Approach 2:
The seal is housed within a cavity of the intermediate casing when in the retracted position, effectively nesting the seal within the casing structure when not in use. This prevents the seal from obstructing the aerodynamic flow while maintaining sealing capability when needed.
2Area of stationary object
If the opening angle of the discharge door is increased to compensate for loss in scooped airflow, then aerodynamic flow is improved, but the opening angle is very limited and does not compensate for this loss
Solution Approach 1:
Instead of increasing the opening angle in one dimension (rotational movement), the solution moves the seal in another dimension (axial retraction into the cavity) to clear the flow path. This allows the door to maintain its limited opening angle while still achieving full aerodynamic flow capability.
Data Source
Figure 1~2
Figure 3~4
AI summary
Discharge valve (48) of an aircraft turbomachine (10), comprising a discharge gate (50) intended to be mounted pivotably about an axis (51) between a position for closing an air passage orifice (60) and an open position of said orifice, the orifice being formed in an intermediate casing (26) of the turbomachine, the discharge valve comprising a sealing device (70) comprising: • - a seal (72) configured to be movably mounted on the intermediate casing (26), and • - a movement system (74) configured to move the seal (72) between a first position in which the seal (72) is intended to bear against the discharge gate (50) when the gate is in a closure position, and a second position in which the seal (72) is retracted with respect to the air passage orifice (60) when the discharge gate (50) is in an open position.