Heat-Capacitance Control Ring for Turbine Tip Clearance
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Solution Overview
Problem
Conventional blade tip clearance systems in gas turbine engines face inefficiencies due to large tip clearances resulting from thermal response mismatches between rotating and static structures, leading to reduced performance and component life.
Innovation Solution
A control ring with an internal cavity filled with a fluid having higher heat capacitance than the control ring itself, such as water or liquid ammonia, is used to improve thermal isolation and reduce thermal response rate, mirroring the rotor disk's properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a static structure with rapid thermal response is used, then thermal response rate is improved, but tip clearance closes significantly during rapid decelerations
Solution Approach 1:
The control ring incorporates a fill material with higher heat capacitance than the control ring itself, fundamentally changing the thermal parameters of the static structure. This allows the static structure to mimic the slower thermal response characteristics of the rotor disk, reducing thermal response rate mismatch and minimizing tip clearance variations during rapid decelerations while maintaining adequate clearance during accelerations
2Stability of the object's composition
If a static structure with slow thermal response is used, then tip clearance stability is improved, but efficiency decreases due to large tip clearances
Solution Approach 1:
By introducing a fill material with higher heat capacitance into the control ring, the thermal response characteristics of the static structure are optimized to match the rotor disk's slower thermal response. This parameter change enables the static structure to maintain stable tip clearance while reducing energy losses, as the controlled thermal expansion and contraction minimize clearance variations without requiring excessively large initial clearances
3Stability of the object's composition
If thermal isolation is increased between control ring and outer air seal, then thermal response control is improved, but heat transfer capability may be reduced
Solution Approach 1:
The control ring design implements differentiated thermal management: the inner surface adjacent to the fill material provides thermal isolation to control the thermal response and minimize tip clearance, while the outer surface maintains necessary heat transfer capability for thermal management. This local quality differentiation allows the static structure to achieve both thermal response control and adequate heat transfer functionality
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 thermal control and efficiency by minimizing tip clearance, thereby improving performance and extending component life in gas turbine engines.
Implementation Method 1
the fill material having a higher heat capacitance than the control ring; wherein the fill material is a fluid sealed inside the internal cavity
Implementation Method 2
thermal isolation from an outer air seal
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A control ring (301) for use in a gas turbine engine (20) includes a control ring segment (307) defining a centerline axis. The control ring segment includes an inner diameter surface (311), an outer diameter surface (313) and an internal cavity (317) defined between the inner and outer diameter surfaces. The internal cavity is configured to contain a material (319) having a higher heat capacitance than the control ring.