Gas Turbine Rotor Axial Clearance Adjustment via Differential Thermal Expansion
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Solution Overview
Problem
Conventional gas turbines lack a mechanism to adjust axial clearance of the rotor during the starting phase, leading to changes in the positions of vanes and blades, which affects the aerodynamic characteristics, output, and efficiency of the turbine.
Innovation Solution
A gas turbine rotor design featuring a first rotor, a second rotor, and a connecting member with different thermal expansion coefficients, where the connecting member is bolted to both rotors and includes passages for cooling fluid, allowing for precise adjustment of axial length and radial clearance through thermal expansion management.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional gas turbine rotor design is used, then the structure is simple, but the axial clearance cannot be adjusted during starting phase, causing changes in aerodynamic characteristics and reducing efficiency
Solution Approach 1:
The rotor is divided into multiple segments including a first rotor, a second rotor, and a connecting member. This segmentation allows independent thermal expansion of each segment, enabling axial clearance adjustment without requiring a complete rotor redesign, thus resolving the contradiction between reliability and complexity.
Solution Approach 2:
The connecting member is made of a material with a thermal expansion coefficient different from the rotors. This parameter change in material property allows the connecting member to expand or contract differently under thermal conditions, automatically adjusting axial clearance to maintain stability while keeping the overall structure relatively simple.
2Productivity
If axial clearance is not adjusted during starting phase, then the rotor structure remains unchanged, but the positions of vanes and blades change due to thermal expansion, affecting output and efficiency
Solution Approach 1:
The invention deliberately utilizes thermal expansion by selecting a connecting member material with a different thermal expansion coefficient from the rotors. During the starting phase, as temperature changes, the connecting member expands or contracts to adjust axial clearance, maintaining precise positions of vanes and blades. This ensures optimal aerodynamic characteristics and maximizes gas turbine output while preserving manufacturing precision.
3Adaptability or versatility
If a connecting member with different thermal expansion coefficient is used, then axial length can be adjusted, but the rotor structure becomes more complex
Solution Approach 1:
The connecting member acts as an intermediary element between the first rotor and the second rotor. By introducing this intermediate component with specific material properties, the system gains axial length adjustment capability through thermal expansion while avoiding the need to redesign the entire rotor structure. The connecting member mediates the thermal effects and enables adaptability with minimal added complexity.
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 design enables stable and precise adjustment of axial length and radial clearance, improving the efficiency and output of the gas turbine by managing thermal expansion and maintaining optimal aerodynamic characteristics.
Implementation Method 1
a connecting member mounted between the insertion hole and the insertion part to connect the first rotor and the second rotor together, and made of a material having a thermal expansion coefficient different from a thermal expansion coefficient of both the first rotor and the second rotor
Data Source
AI summary
A gas turbine rotor includes: a first rotor in a shaft shape extending by a predetermined length in an axial direction, and provided with an insertion hole at an end of the first rotor; a second rotor in a shaft shape extending by a predetermined length in the axial direction, and provided with an insertion part extending by a predetermined length at an end of the second rotor and corresponding to the insertion hole such that the insertion part is inserted into the insertion hole; and a connecting member mounted between the insertion hole and the insertion part to connect the first rotor and the second rotor together, and made of a material having a thermal expansion coefficient different from a thermal expansion coefficient of both the first rotor and the second rotor.