Turbine Engine Seal Support Assembly for Dynamic Radial Clearance
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Solution Overview
Problem
Gas turbine engines face challenges in maintaining effective radial clearance between rotor shafts and seal members across varying operating conditions, leading to potential rotor scrub and excessive wear due to low film bearing stiffness during low delta pressure conditions and transients.
Innovation Solution
A seal member support system utilizing a tangential spring-based retraction mechanism to hold seal members radially away from the rotor shaft during low-pressure conditions, allowing them to move inwardly as pressure increases to seal radial gaps, and return to a retracted position as pressure decreases, thereby reducing wear and preventing rotor scrub.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seal members are held radially outward to maintain clearance during low-pressure conditions, then rotor scrub and wear are reduced, but radial gap sealing effectiveness deteriorates
Solution Approach 1:
The seal support assembly incorporates a spring mechanism that enables dynamic adjustment of seal member radial position. During low-pressure conditions, the spring forces the seal member radially outward to maintain clearance and prevent rotor scrub. During high-pressure conditions, the spring allows the seal member to move radially inward to seal the radial gap, thus resolving the contradiction between wear reduction and sealing effectiveness.
Solution Approach 2:
The system changes the radial position parameter of the seal member based on operating pressure conditions. The spring mechanism transforms pressure differential changes into radial position changes, allowing the seal member to automatically adjust its position between retracted (low-pressure) and extended (high-pressure) states, addressing both wear and sealing requirements.
2Object-affected harmful factors
If seal members are allowed to move inward to seal radial gaps during high-pressure conditions, then sealing effectiveness improves, but rotor scrub and wear increase during low-pressure conditions
Solution Approach 1:
The spring mechanism performs preliminary action by pre-positioning the seal member radially outward during low-pressure conditions before high-pressure conditions occur. This proactive positioning prevents rotor scrub and wear during transient and low-pressure operation, while still allowing inward movement when high-pressure sealing is required.
3Reliability
If a fixed radial clearance is maintained between seal members and rotor shaft, then wear is reduced, but sealing effectiveness during high-pressure conditions deteriorates
Solution Approach 1:
The invention transitions from a fixed clearance system to a dynamic clearance system. The spring mechanism allows the radial clearance to vary automatically with operating conditions: larger clearance during low-pressure conditions to prevent wear, and smaller clearance during high-pressure conditions to maintain sealing effectiveness.
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 system effectively maintains a consistent radial clearance and reduces wear on rotor shafts and seal members by passively controlling the radial position of seal members, enhancing the durability and efficiency of gas turbine engines across different operating conditions.
Implementation Method 1
a spring arrangement having a spring extension extending between the carrier and the first seal segment to counter a pressure on an outer pressurization surface of a lip of the first seal segment during operation of the turbine engine
Data Source
AI summary
A turbine engine is provided. The gas turbine engine defines a radial direction and includes: a rotor; a stator comprising a carrier; a seal assembly disposed between the rotor and the stator, the seal assembly comprising a plurality of seal segments, the plurality of seal segments having a seal segment, the seal segment having a seal face configured to form a fluid bearing with the rotor; and a seal support assembly, the seal support assembly comprises a pneumatic engagement assembly operable to bias the seal segment along the radial direction during operation of the turbine engine.