Gas Turbine Mini-Disk Radial Fit and Thermal Stress Management
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Solution Overview
Problem
Mini-disks in gas turbine engines are prone to failure due to high thermal and operational stresses, leading to shorter operational lifespans compared to other components.
Innovation Solution
The mini-disk design incorporates two radial snaps and eliminates the bore, integrating it into the main rotor stack with a heat shield and balancing elements, allowing it to transmit loads directly to the turbine disk, reducing stress and incorporating a discourager to manage airflow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the mini-disk is positioned radially within the gas turbine engine and subjected to high thermal and operational loads, then it can perform its function of connecting turbine disk and compressor, but it suffers failure prior to other components due to high thermal stresses and rotational loads
Solution Approach 1:
The mini-disk is divided into three distinct portions: a radially extending portion, an axially extending portion, and an intermediate portion. This segmentation allows each portion to be optimized for its specific functional requirements, with the intermediate portion serving as a transition zone that manages stress distribution between the radial and axial sections, thereby improving overall reliability under thermal and operational loads.
Solution Approach 2:
The mini-disk incorporates features with locally optimized properties: discouragers are strategically placed on specific surfaces to manage airflow and reduce thermal loading in critical areas, while the intermediate portion has a geometry specifically designed to handle stress concentration. This local quality approach ensures that thermal stresses are mitigated where most critical without compromising the overall structural integrity.
2Ease of operation
If the mini-disk is designed as a self-supporting component positioned radially within the engine, then it can operate independently, but it is subject to high loads and stresses causing premature failure
Solution Approach 1:
The mini-disk is integrated into the main rotor stack by combining it with both the turbine disk (via the radially extending portion) and the compressor (via the axially extending portion). This merging allows the mini-disk to transmit loads directly to these larger, stronger components, distributing the high operational loads and reducing stress concentration in the mini-disk itself while maintaining its self-supporting capability.
Solution Approach 2:
The intermediate portion acts as a mediator between the radially extending portion and the axially extending portion. It provides a transition geometry that facilitates smooth load transfer and stress distribution between the two orthogonal directions, enabling the mini-disk to maintain self-supporting capability while reducing peak stresses through optimized geometric transition.
3Ease of manufacture
If the mini-disk incorporates traditional bore design, then it can be manufactured using conventional methods, but it experiences fit loss due to creep under high thermal and operational stresses
Solution Approach 1:
The invention eliminates the bore feature entirely from the mini-disk design. By removing this stress-concentrating geometric discontinuity, the mini-disk no longer experiences fit loss due to creep under thermal and operational loads. This extraction of the problematic feature maintains manufacturing simplicity while dramatically improving radial fit tolerance and overall precision under operating conditions.
4Reliability
If the mini-disk is located between the turbine disk and hot gases, then it can perform its sealing and support functions, but it is exposed to high thermal loads reducing its operational life
Solution Approach 1:
Discouragers are strategically placed on specific surfaces of the mini-disk to locally modify airflow patterns. These discouragers create regions of reduced thermal loading by directing hot gases away from critical surfaces while maintaining the sealing function. This local quality approach allows the mini-disk to perform its sealing function reliably while mitigating thermal loads in the most vulnerable areas.
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 configuration enhances the mini-disk's operational life by maintaining stress within acceptable limits, preventing fit loss due to creep, and ensuring a tight radial fit during operation, thus extending its lifespan.
Implementation Method 1
a heat shield configured to thermally protect the axially extending portion from high temperatures
Implementation Method 2
a discourager extending from at least one of the radially extending portion, the intermediate portion, or a junction between the intermediate portion and the radially extending portion, wherein the discourager is configured to discourage air flow along a surface of the mini-disk
Data Source
Figure 1A
Figure 1B
Figure 2
AI summary
Mini-disks (314) of gas turbine engines (300) are provided having an axially extending portion (340) extending axially with respect to an axis of the engine, the axially extending portion configured to engage with a hub arm (355) of a compressor of the engine, a radially extending portion (342) extends radially with respect to the axis, the radially extending portion configured to engage with an attachment (318) of a turbine disk of the gas turbine engine, an intermediate portion (344) extending between the axially extending portion and the radially extending portion, and at least one mini-disk connector (346, 348) configured to engage with a portion of the turbine disk of the gas turbine engine to prevent radial movement of the mini-disk during operation.