Gas Turbine Duct Blocker Seal Assembly for Thermal Expansion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Gas turbine engines face challenges in modulating airflow for V/STOL operations and selectively controlling third stream airflow in variable cycle engine architectures, particularly due to thermal expansion differences between materials and high operational pressures and temperatures, which affect sealing systems and airflow modulation.
Innovation Solution
A duct blocker system with a blocker ring, tab, cover plate, compliant seals, and a spring mechanism, where the outer case and blocker ring are made of different materials, and an actuator is used to rotate the blocker ring, along with a sealing system that includes a seal carrier and compliant seals to accommodate thermal growth and high pressures, ensuring effective sealing and airflow modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the outer case and blocker ring are made of different materials to accommodate thermal expansion differences, then thermal growth accommodation is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by selecting materials with different thermal expansion coefficients for the outer case and blocker ring. This allows each component to expand at different rates during operation, accommodating thermal growth without compromising seal integrity or requiring complex compensation mechanisms.
Solution Approach 2:
The patent employs composite material construction by combining different materials for the outer case and blocker ring. This composite approach enables the system to handle differential thermal expansion while maintaining structural integrity and simplifying the overall design compared to using uniform materials throughout.
2Reliability
If compliant seals are used to accommodate thermal expansion and high pressures, then sealing reliability is improved, but device complexity increases
Solution Approach 1:
The patent utilizes flexible compliant seals that can deform elastically to accommodate thermal expansion and pressure variations. These flexible sealing elements maintain reliable seals under varying operational conditions without requiring complex mechanical compensation devices or multiple sealing stages.
Solution Approach 2:
The compliant seals provide dynamic sealing capability, allowing the sealing interface to adapt continuously to thermal growth and pressure changes. This dynamic response maintains seal integrity throughout operation without requiring complex control mechanisms or rigid precision-machined interfaces.
3Reliability
If a spring mechanism is added to the sealing system to maintain seal contact under high pressure, then sealing effectiveness is improved, but device complexity increases
Solution Approach 1:
The spring mechanism acts as a counterbalancing element that applies continuous contact force to the compliant seals, counteracting the separating effect of high pressure. This ensures maintained seal contact and effectiveness throughout the pressure cycle without requiring complex active control systems.
Solution Approach 2:
The spring pre-loads the compliant seals against the sealing surfaces before pressure application, ensuring immediate seal contact and preventing leakage. This preliminary action eliminates the need for complex pressure-responsive sealing mechanisms.
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 seals and modulates airflow, accommodating thermal expansion and high operational conditions, enhancing the engine's ability to perform V/STOL operations and variable cycle engine control while maintaining seal integrity and reducing service life issues.
Implementation Method 1
a spring between the second support and the first support
Implementation Method 2
an outer compliant seal supported by the first support to seal with the cover plate; an inner compliant seal supported by the second support to seal with the blocker ring
Data Source
AI summary
A seal system for a gas turbine engine includes a cover plate with a radial flange; a seal carrier adjacent the cover plate; an outer compliant seal supported by the seal carrier; an inner compliant seal supported by the seal carrier, the inner compliant seal engaged with the radial flange; and a spring between the cover plate and the seal carrier.