ACC Valve Assembly for Differential Turbine Cooling Flow
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Solution Overview
Problem
Conventional active clearance control systems for gas turbine engines are complex, require frequent maintenance, and are not adaptable for controlling complex cooling flow relationships without adding weight and complexity, making it difficult to achieve optimal efficiency due to differential expansion rates of turbine case and blades.
Innovation Solution
A valve assembly with a housing, annular inlet and outlet ducts, and rotating valve discs, along with a flow control member that restricts fluid flow differentially between the ducts, allowing for precise control of cooling airflow to various turbine sections using a single shaft and actuator, reducing the number of parts and weight while enhancing adaptability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple separate ACC systems or complex valve assemblies with multiple actuators and gears are used to control differential cooling airflows to different turbine case sections, then the required differential cooling airflow control is achieved, but the device complexity and weight increase
Solution Approach 1:
The patent combines multiple valve elements into a single integrated valve assembly that controls differential cooling airflows to different turbine case sections. The assembly includes a housing with multiple outlet ducts, each having a valve element, and a single actuator that rotates a common shaft to simultaneously control all valve elements. This merging of multiple independent control mechanisms into one unified assembly reduces device complexity while maintaining the capability to control complex flow relationships.
Solution Approach 2:
The single actuator and common shaft design enables one mechanism to perform multiple functions by controlling several valve elements simultaneously. The valve assembly can direct cooling airflow to multiple different turbine case sections with different flow requirements using a single actuation mechanism, providing multi-functionality without increasing the number of actuators or complex mechanical linkages.
2Adaptability or versatility
If multiple separate ACC systems or complex valve assemblies with multiple actuators and gears are used to control differential cooling airflows, then the required differential cooling airflow control is achieved, but maintenance requirements increase
Solution Approach 1:
By merging multiple valve elements into a single integrated assembly with a common actuator and shaft, the patent reduces the total number of mechanical components that require maintenance. Fewer separate actuators, gears, and linkages mean fewer potential failure points and simplified maintenance procedures while maintaining the capability to control complex differential cooling flow relationships.
3Adaptability or versatility
If conventional ACC systems are used, then cooling airflow is provided to turbine case sections, but the system cannot be readily adapted for controlling more complex cooling flow relationships without adding complexity and weight
Solution Approach 1:
The integrated valve assembly design merges multiple control functions into a single lightweight structure, eliminating the need for multiple separate actuators and mechanical linkages that would increase weight. The assembly can be adapted to control complex cooling flow relationships by modifying the valve element configuration or outlet duct arrangement without adding significant weight.
Solution Approach 2:
The valve assembly incorporates adjustable and reconfigurable elements that allow it to adapt to different cooling flow requirements. The valve elements can be positioned at different angles or configurations to control differential cooling airflows to various turbine case sections, providing dynamic adaptability without requiring additional heavy mechanical components.
Data Source
AI summary
A valve assembly for an active clearance control (ACC) system in a gas turbine engine. The assembly comprises a first valve disc positioned within a first outlet duct, a second valve disc positioned within the second outlet duct, and a shaft coupled to the first and second valve discs such that rotation of the shaft rotates both the first and second valve discs within the first and second outlet ducts, respectively. A flow control member in the second outlet duct surrounds the second valve disc, and is configured to restrict fluid flow passing through the second outlet duct to a greater extent than the fluid flow passing through the first outlet duct for a given degree of rotation of the first and second valve discs. A corresponding ACC system, gas turbine and method is also provided.