Slidable Coupling Impeller Shroud for Centrifugal Compressor Clearance Control
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Solution Overview
Problem
Centrifugal compressor systems in gas turbine engines face inefficiencies due to large blade tip clearances that prevent rubs but result in high leakage, and existing adjustment systems are cumbersome, heavy, and power-intensive.
Innovation Solution
A dynamically moveable impeller shroud assembly with a slidable coupling to the engine casing, actuated by pneumatic, hydraulic, electric, or thermal means, allowing axial movement while maintaining radial alignment to adjust blade tip clearance based on sensor measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blade tip clearance is increased to prevent rubs, then reliability is improved, but leakage increases and efficiency deteriorates
Solution Approach 1:
The shroud is made dynamically moveable along the axial direction through a slidable coupling mechanism, allowing the blade tip clearance to be adjusted in real-time based on operating conditions. This dynamic adjustment enables the system to maintain optimal clearance that prevents rubs while minimizing leakage, resolving the contradiction between reliability and energy loss.
Solution Approach 2:
The system changes the clearance parameter dynamically by actuating the shroud position along the axial direction. Sensors detect operating conditions and control systems adjust the shroud position to optimize clearance, transforming the static clearance into a variable parameter that adapts to different operating states to balance reliability and efficiency.
2Device complexity
If rigid mounting of shroud to casing is used, then device complexity is reduced, but adaptability deteriorates
Solution Approach 1:
A slidable coupling mechanism serves as an intermediary between the shroud and engine casing, allowing relative axial movement while maintaining radial alignment. This intermediary component enables clearance adjustment without requiring complex linkages or mounting structures, achieving adaptability with minimal increase in device complexity.
Solution Approach 2:
The invention replaces traditional mechanical linkage systems with a slidable coupling that allows direct axial movement of the shroud. This substitution eliminates complicated linkages while providing the necessary adaptability for clearance control, reducing device complexity while maintaining versatility.
3Adaptability or versatility
If existing actuation systems are used, then blade tip clearance adjustment is achieved, but weight and power consumption increase
Solution Approach 1:
The invention extracts and eliminates unnecessary components from traditional actuation systems by using a slidable coupling mechanism that allows direct axial movement. This extraction of essential functionality while removing extraneous parts reduces the weight of the actuation system while maintaining clearance adjustment capability.
Solution Approach 2:
The slidable coupling mechanism enables the shroud to move axially through its own structural design rather than requiring heavy external actuation systems. The system uses the engine's operating conditions (detected by sensors) to drive the clearance adjustment, reducing the need for additional power-intensive mechanical systems.
Data Source
AI summary
A system for controlling the clearance distance between an impeller blade tip of a centrifugal compressor and a radially inner surface of an impeller shroud in a turbine engine. The system comprises a high pressure air source, an air piston mounted between an engine casing and the shroud and adapted to receive high pressure air from the high pressure air source, a mounting arm coupling the shroud and air piston, and a slidable coupling adapted to allow axial movement of the shroud and joining the shroud to an axial member.