Gas Turbine Rotor Asymmetric Clearance Positioning
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Solution Overview
Problem
The existing rotor designs for gas turbines with interconnected rotor disks and an annular rotor component face challenges in maintaining the position of the rotor component during thermal expansions and centrifugal forces, leading to potentially unacceptably high compressive stresses.
Innovation Solution
The rotor design features a first and second rotor disk with blade holding grooves and fastening projections, where the annular rotor component is positioned between the disks, with specific annular grooves and projections that engage to ensure a defined position without excessive stress, allowing for stress-free connection at room temperature and adapting to thermal expansions during startup and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor component is press-fitted to the rotor disk to ensure correct positioning, then the rotor component is secured against displacement, but unacceptably high compressive stresses occur during rotation due to centrifugal forces
Solution Approach 1:
The mounting projection is designed with asymmetric clearance distribution: smaller clearance on the inner side (toward rotor axis) and larger clearance on the outer side. This dynamic clearance distribution allows the rotor component to maintain reliable positioning while accommodating thermal expansions and centrifugal forces during rotation, preventing unacceptably high compressive stresses.
Solution Approach 2:
The invention changes the geometric parameters of the mounting projection by introducing asymmetric clearances between the projection and the rotor component. The inner clearance is deliberately made smaller than the outer clearance, creating an optimal balance between positioning reliability and stress reduction during operational conditions.
2Reliability
If the rotor component is press-fitted to prevent hot gas ingress, then sealing effectiveness is improved, but loss of compressive stress occurs during thermal expansion and contraction
Solution Approach 1:
The asymmetric clearance design allows the mounting projection to dynamically adapt to thermal expansions and contractions. The smaller inner clearance maintains sealing effectiveness against hot gas, while the larger outer clearance provides space for thermal expansion, preventing loss of compressive stress during temperature cycles.
3Weight of moving object
If the rotor component is made thin-walled to reduce weight, then weight reduction is achieved, but the component becomes more susceptible to deformation under centrifugal forces
Solution Approach 1:
The rotor component is designed with locally optimized thickness: thin-walled in most areas to reduce weight, but with a strategically positioned mounting projection that provides localized structural reinforcement. The asymmetric clearance design in the mounting projection further compensates for the reduced overall thickness, allowing the thin-walled component to resist centrifugal deformation while maintaining weight advantages.
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 design ensures the secure positioning of the rotor component and absorption of centrifugal forces, preventing excessive stress and maintaining the rotor's integrity during heating, cooling, and operation, while allowing for efficient assembly and operation at nominal speed.
Implementation Method 1
the combination of the intended press fit with the deformations caused by centrifugal forces due to rotor rotation can lead to potentially unacceptably high compressive stresses
Implementation Method 2
different thermal expansions can occur in the rotor disks and the rotor component, depending on the design of the press fit and the possible elastic deformations during heating and cooling of the gas turbine
Data Source
Figure 1~2
Figure 3~5
Figure 6~8
AI summary
The invention relates to a rotor of a gas turbine comprising two adjacent rotor discs (01, 11), on each of which moving blades are fastened, an annular rotor component (21) being arranged between the rotor discs (01, 11) and having at its opposite ends circumferential annular grooves (24, 34), in each of which a circumferential fastening projection (04, 14) on the respective rotor disc (01, 11) engages. According to the invention, when the rotor is stationary a first outer flank (25) of the first annular groove (24) rests under pressure against a first outer flank (05) of the first fastening projection (04) and there is play between a first inner flank (26) of the first annular groove (24) and a first inner flank (06) of the first fastening projection (04).