Segmented Securing Device for Turbomachine Rotor Blades
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Solution Overview
Problem
Current securing devices for rotor blades in turbomachines face challenges such as high weight, complex designs, and limited temperature resistance due to centrifugal forces and temperature gradients, leading to potential material stress and reduced service life.
Innovation Solution
A securing device with multiple segments that distribute centrifugal forces directly to the disc wheel, featuring active surfaces interacting with both the disc wheel and rotor blades, allowing for axial support and temperature expansion, thereby reducing stress and weight while maintaining structural integrity across temperature gradients.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If securing segments are used to axially secure rotor blades, then the axial length of blade roots and disc wheel can be reduced, but the securing segments cannot reliably absorb centrifugal forces during operation
Solution Approach 1:
The securing device is divided into multiple securing segments arranged circumferentially, allowing each segment to independently interact with the disc wheel and rotor blade while collectively absorbing centrifugal forces. This segmentation enables reliable force absorption with reduced axial dimensions.
2Reliability
If a full ring securing device is used, then centrifugal forces can be reliably absorbed, but the device cannot withstand high temperatures and temperature gradients due to material stress and potential fracture
Solution Approach 1:
The full ring is divided into multiple securing segments with circumferential gaps, allowing each segment to expand independently in response to temperature gradients. This prevents the buildup of thermal stress that would occur in a continuous full ring, enabling operation at high temperatures.
Solution Approach 2:
The securing segments are designed with adjustable engagement depths and active surface geometries that can be optimized for different temperature conditions. The circumferential gaps allow thermal expansion while maintaining mechanical engagement, adapting the device to high-temperature operation.
3Weight of moving object
If the axial length of rotor blades and disc wheel is reduced, then the weight of the rotor device is reduced, but the structural integrity under centrifugal forces may be compromised
Solution Approach 1:
Multiple securing segments distribute the load-bearing function across different circumferential positions, allowing the use of shorter blade roots and disc wheel while maintaining overall structural integrity. Each segment contributes to the collective strength needed to withstand centrifugal forces.
Solution Approach 2:
The securing segments combine multiple functions into a single component: axial securing, centrifugal force absorption, and thermal expansion accommodation. This integration allows weight reduction without sacrificing structural integrity.
4Reliability
If securing segments are supported on rotor blades during operation, then centrifugal forces can be absorbed, but the disc wheel and blade roots must be made larger, increasing weight
Solution Approach 1:
The securing segments act as intermediaries between the disc wheel and rotor blade, transferring centrifugal forces directly between these components without requiring increased size of either. The segments provide a dedicated force transmission path that maintains reliability while minimizing weight.
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 effectively reduces the axial length of rotor blades and disc wheels, minimizing weight and stress, while ensuring long-term operation even under high temperature gradients, and simplifies the design to reduce complexity and costs.
Implementation Method 1
When the jet engine is in operation, the centrifugal forces acting on them as a result of the rotation of the rotor device push the securing segments outwards in the radial direction
Implementation Method 2
the full ring, in contrast to a segmented solution, also transmits circumferential stresses and cannot expand in the circumferential direction
Data Source
Figure 1
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AI summary
A locking device (22) with several locking segments (23) for axially securing at least one impeller blade (18) to a disk wheel (17) of a rotor assembly (10B) of a turbomachine (1) is proposed. The locking device (22) has at least one effective surface (27) arranged in a radially inner region, which, in the assembled state, is configured to interact with the disk wheel (17) in the axial direction (A) of the rotor assembly (10B), and another effective surface (31) arranged in a radially outer region on a locking segment (23), which, in the assembled state, is configured to interact with at least one impeller blade (18) in the axial direction (A) of the rotor assembly (10B). At least one locking segment (23) has an additional effective surface (35) which, in the assembled state, is configured to interact with the disk wheel (17) in the radial direction (R) of the rotor assembly (10B).Furthermore, a rotor device (10B) with such a safety device (22) is described.