Gas Turbine Vane Carrier Clearance Control
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Solution Overview
Problem
Gas turbine assemblies face inefficiencies due to leakage flows caused by excessive clearances between rotating blades and stator vane carriers, which are designed to prevent contact but result in reduced efficiency, and existing active control solutions are not sufficiently effective.
Innovation Solution
A gas turbine assembly with a governing ring that includes clearance control cavities and a discharge conduit system to actively manage thermal expansion and optimize thermo-mechanical behavior, allowing for controlled clearance adjustment and reduced fluid usage, with optional inserts for enhanced heat transfer and material flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If larger clearances are designed between rotating blades tips and stator vane carrier to guarantee safe operation and avoid contact, then reliability is improved, but leakage flows increase causing loss in efficiency
Solution Approach 1:
The patent implements active clearance control by dynamically adjusting the stator vane carrier position using actuators (hydraulic, pneumatic, or electric) based on real-time temperature and clearance measurements. This dynamic adjustment allows the system to maintain optimal clearances under varying operating conditions, resolving the contradiction between maintaining safe operation clearances and minimizing leakage losses.
Solution Approach 2:
The system employs sensors to continuously monitor clearance dimensions and temperature, feeding this information back to a control system that adjusts actuator commands accordingly. This closed-loop feedback mechanism enables real-time optimization of clearances, ensuring both reliability through contact prevention and efficiency through minimized leakage flows.
2Loss of energy
If active control clearance solutions are implemented to regulate clearance, then efficiency is improved by minimizing leakages, but device complexity increases
Solution Approach 1:
The patent introduces a governing ring as an intermediary component that provides clearance control cavities. These cavities act as intermediaries between the control system and the vane carrier, enabling thermal expansion control that indirectly adjusts clearances. This approach simplifies the overall control architecture compared to direct actuation of the vane carrier.
Solution Approach 2:
The system controls clearance by changing thermal parameters - specifically by introducing controlled amounts of fluid into clearance control cavities to induce thermal expansion of the governing ring and vane carrier. This parameter-based control (temperature/pressure of control fluid) is simpler than mechanical positioning systems and enables efficient clearance regulation.
3Loss of energy
If thermal expansion is obtained directly in the vane carrier to control clearance, then clearance control is achieved, but significantly more fluid is required
Solution Approach 1:
The governing ring is nested within the vane carrier structure, with clearance control cavities positioned inside the governing ring which itself is inside the vane carrier assembly. This nested configuration allows the control system to influence the vane carrier's thermal expansion indirectly through the governing ring, requiring significantly less control fluid than direct vane carrier actuation would demand.
Solution Approach 2:
The governing ring serves as a thermal intermediary - a relatively small component that, when thermally expanded through controlled fluid introduction, can induce proportional expansion in the larger vane carrier. This leverage effect allows minimal fluid quantities to achieve the desired clearance control effect that would otherwise require large fluid volumes for direct vane carrier heating.
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 solution provides a more efficient and flexible design that minimizes leakage while maintaining safe operation, achieving better thermal management and increased useful work output by actively controlling clearances along the entire circumferential portion of the vane carrier.
Implementation Method 1
a governing ring (28) housed in an annular seat (27) of the vane carrier (10), said governing ring (28) comprising at least one clearance control cavity (29) which extends transversally with respect to a longitudinal axis (A) for controlling the turbine clearance (16)
Data Source
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AI summary
A gas turbine assembly is provided with at least one vane carrier (10; 20) extending along a longitudinal axis (A) and comprising at least one annular seat (27) and with at least one governing ring (28; 128) housed in the annular seat (27) and comprising at least one clearance control cavity (29; 140) which extends transversally with respect to the longitudinal axis (A).