Turbine Seal Assemblies with Passive Flow Regulators
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Solution Overview
Problem
Current seal assemblies for rotary machines, such as turbine engines, face challenges in maintaining effective sealing and fluid flow regulation across varying operating conditions, leading to issues like increased leakage and contact between seal and rotor faces, especially under changing pressure differentials.
Innovation Solution
The introduction of passive flow regulators that adjust hydraulic resistance in aspiration conduits through movable flow constrictors, which change dimensions in response to pressure changes, ensuring a consistent fluid flow and suitable hydraulic stiffness across a range of operating conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seal assemblies are used to reduce fluid leakage between rotors and stators, then sealing performance is improved, but leakage increases under varying operating conditions
Solution Approach 1:
The patent applies dynamics by making the flow resistance characteristic adaptable to operating conditions. The seal assembly transitions from a static sealing structure to a dynamic one that automatically adjusts its flow resistance based on pressure differential and operating conditions, thereby maintaining optimal sealing performance across varying conditions without increasing leakage.
Solution Approach 2:
The patent changes the parameter of flow resistance from a fixed value to a variable that responds to operating conditions. By incorporating elements that modify flow resistance based on pressure differential and other operating parameters, the seal assembly maintains effective sealing performance while preventing excessive leakage under varying conditions.
2Adaptability or versatility
If seal assemblies are designed to maintain sealing across varying operating conditions, then adaptability is improved, but contact between seal and rotor faces occurs
Solution Approach 1:
The patent applies pneumatic principles by using fluid pressure differentials to control the flow resistance characteristics of the seal assembly. The aspirating flow regulators utilize hydraulic/pneumatic forces to automatically adjust sealing parameters in response to operating conditions, maintaining adaptability while preventing harmful contact events through non-contact sealing mechanisms.
Solution Approach 2:
The patent implements feedback mechanisms where the seal assembly's flow resistance automatically responds to changes in operating conditions such as pressure differential. This self-regulating feedback system maintains optimal sealing performance and adaptability while preventing contact events by adjusting flow characteristics in real-time based on the actual operating state.
3Quantity of substance
If aspiration conduits are used to provide fluid flow to the seal interface, then fluid flow is improved, but hydraulic resistance varies under changing operating conditions
Solution Approach 1:
The patent applies dynamics to the aspiration conduits by incorporating aspirating flow regulators that make the hydraulic resistance characteristic adaptable. The conduits transition from having fixed resistance to dynamically adjusting resistance based on operating conditions, ensuring consistent fluid flow delivery to the seal interface regardless of pressure differential changes.
Solution Approach 2:
The patent changes the hydraulic resistance parameter from a fixed value to one that varies in response to operating conditions. The aspirating flow regulators modify the flow resistance characteristics based on pressure differential and other parameters, maintaining optimal fluid flow quantity to the seal interface while compensating for variations in hydraulic resistance under different operating conditions.
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
This solution enhances the sealing performance by reducing leakage and contact events, maintaining effective fluid flow and hydraulic stiffness, even under aberrant operating conditions, thereby improving the durability and operational efficiency of rotary machines.
Implementation Method 1
The passive flow regulators may be configured to change a hydraulic resistance of the one or more aspiration conduits in response to a pressure differential across the seal assembly
Implementation Method 2
the passive flow regulators respectively regulate a flow of fluid through the one or more aspiration conduits as a function of fluid pressure
Data Source
AI summary
A seal assembly for an aeronautical turbine engine includes a passive flow regulator. The passive flow regulator includes a seal body defining an aspiration conduit, and a flow constrictor disposed within and/or adjacently upstream of the aspiration conduit. The aspiration conduit provides fluid communication across the seal body from a relatively higher-pressure fluid volume to a relatively lower-pressure fluid volume. The flow constrictor includes one or more flexure elements that move in one or more degrees of freedom as a result of changes in a pressure differential across the flow constrictor. The movement of the one or more flexure elements changes a hydraulic resistance of fluid flow past the flow constrictor based at least in part on a position of the flow constrictor in relation to the aspiration conduit.