Turbine Blade Tip Clearance Control via Actuator Ring
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Solution Overview
Problem
Existing gas turbines face efficiency issues due to inconsistent turbine blade tip clearance, which can lead to reduced performance if clearance is too high or risk damage if too low, and existing control mechanisms are complex and inefficient.
Innovation Solution
An apparatus that uses an actuator ring outside the turbine casing to rotate and move ring segments circumferentially within the casing, adjusting tip clearance uniformly across multiple blades through a link member, eccentric member, and pusher mechanism, supported by roller bearings and elastic restoration devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the tip clearance is increased, then the blade is protected from scratching the turbine casing, but the combustion gas discharge increases and overall efficiency decreases
Solution Approach 1:
The turbine blade tip clearance control apparatus dynamically adjusts the tip clearance distance between the turbine blade and turbine casing during operation. The actuator ring rotates to move ring segments, which push ring pushers to adjust the clearance, transforming a static clearance into a dynamic one that can be optimized for both protection and efficiency under different operating conditions.
2Loss of energy
If the tip clearance is decreased, then the combustion gas activation improves and efficiency increases, but the blade may scratch the turbine casing
Solution Approach 1:
The system enables dynamic control of tip clearance to maintain an optimal distance that maximizes combustion gas activation while preventing blade-casing contact. The actuator can adjust clearance in real-time based on operating conditions, ensuring the blade remains close enough for efficiency but not so close as to cause scratching.
3Manufacturing precision
If existing control mechanisms are used, then tip clearance can be adjusted, but the control mechanism is complex and inefficient
Solution Approach 1:
The control mechanism merges multiple functions into a unified system. The actuator ring simultaneously controls multiple ring segments that collectively adjust all turbine blade clearances. This integrated approach replaces complex individual blade adjustment mechanisms with a single coordinated system that achieves precise uniform control across all blades.
Solution Approach 2:
The actuator ring serves multiple functions: it rotates to control clearance, transmits motion to multiple ring segments, and coordinates the adjustment of all turbine blades simultaneously. This multi-functional design eliminates the need for separate control mechanisms for each blade, simplifying the overall system while maintaining precision.
4Productivity
If uniform control of multiple turbine blades is achieved, then gas turbine efficiency improves, but the control mechanism requires coordinated movement of multiple components
Solution Approach 1:
The system combines the control of multiple turbine blades into a single actuator ring mechanism. By merging the adjustment functions for all blades into one coordinated system, uniform clearance control is achieved across all blades simultaneously, improving gas turbine efficiency without requiring independently complex mechanisms for each blade.
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 allows for precise and uniform control of turbine blade tip clearance, enhancing gas turbine efficiency by optimizing clearance settings while preventing damage, and simplifying the control mechanism.
Implementation Method 1
a plurality of roller bearings mounted on an outer peripheral surface of the turbine casing to support an inner peripheral surface of the actuator ring
Implementation Method 2
a plurality of elastic restoration devices coupled between the turbine casing and the ring segments, respectively, to restore the ring segments in the radial direction
Data Source
Figure 1
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AI summary
An apparatus for controlling turbine blade tip clearance is provided. The apparatus for controlling turbine blade tip clearance includes a turbine casing configured to guide a flow of combustion gas, an actuator ring rotatably mounted outside the turbine casing, a plurality of turbine blades rotatably mounted inside the turbine casing, a plurality of ring segments surrounding tips of the turbine blades and installed to form a predetermined gap with each tip, a plurality of rotary shafts each configured to have one end connected to several of the plurality of ring segments and the other end extending radially from the turbine casing, a link member configured to rotate an associated one of the rotary shafts according to circumferential rotational motion of the actuator ring, and a pusher member provided at an inner end of the rotary shaft to move the ring segments radially inward by rotation of the rotary shaft.