Axially-Split Radial Turbine Segmentation for Thermal Stress Management
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Solution Overview
Problem
Radial turbines in gas turbine engines face challenges due to high thermal and mechanical stresses, making it difficult to manufacture internally-cooled radial turbines that can withstand high operational speeds and temperatures, leading to premature fatigue and increased costs.
Innovation Solution
An axially-split radial turbine design with internal cooling passages is fabricated using multiple bladed pieces cast from high-temperature-resistant alloys, consolidated into monolithic rings and bonded onto disks, allowing for disparate alloys to be used based on operating conditions, and a directed thermal growth bonding process to form a lightweight and cost-effective structure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If radial turbines are designed to operate at high temperatures and speeds, then power output and efficiency are improved, but thermal and mechanical stresses cause premature fatigue and failure
Solution Approach 1:
The radial turbine is divided into multiple axially-disposed sections (first radial turbine section, second radial turbine section) that can be manufactured separately and then assembled. This segmentation allows each section to be optimized for specific thermal and mechanical conditions, improving overall reliability while maintaining high power output capability.
Solution Approach 2:
The patent employs different alloys for different turbine sections based on their specific operating conditions. The first radial turbine section uses a alloy suitable for higher temperature exposure, while the second section uses a different alloy optimized for its specific conditions. This composite material approach allows the turbine to withstand higher temperatures and speeds without premature fatigue.
2Temperature
If internal cooling passages are added to radial turbine blades, then high-temperature operation is enabled, but manufacturing complexity and cost increase significantly
Solution Approach 1:
By segmenting the turbine into separate axially-disposed sections, internal cooling passages can be incorporated into specific blade sections during their individual manufacturing processes. This avoids the need for complex multi-piece assembly required in traditional single-piece turbines with cooling passages, thereby reducing manufacturing complexity and cost while enabling high-temperature operation.
3Strength
If traditional single-piece radial turbine manufacturing is used, then structural integrity is maintained, but internal cooling features cannot be effectively incorporated
Solution Approach 1:
The turbine is segmented into multiple axially-disposed sections that are manufactured separately with internal cooling features integrated into the blade portions of each section. These sections are then assembled together with axial abutting surfaces, maintaining structural integrity through precise mating surfaces while enabling effective internal cooling throughout the turbine structure.
4Weight of moving object
If radial turbines are made lightweight, then power-to-weight ratio improves, but manufacturing precision and material selection become more challenging
Solution Approach 1:
By dividing the turbine into separate axially-disposed sections, each section can be manufactured with optimized weight and precise dimensional control. The segmentation allows for specialized manufacturing processes for each section, achieving the required manufacturing precision more easily than in a single-piece turbine, while the overall lightweight design improves power-to-weight ratio.
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 axially-split radial turbine design enhances thermal and mechanical capabilities, enabling operation at higher temperatures with improved efficiency and reduced costs, while allowing for tailored alloy selection for different turbine sections, thus overcoming the limitations of traditional manufacturing methods.
Implementation Method 1
a directed thermal growth bonding process to form a lightweight and cost-effective structure
Data Source
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AI summary
Embodiments of an axially-split radial turbine (20) are provided, as are embodiments of a method (110) for manufacturing an axially-split radial turbine (20). In one embodiment, the method includes the steps of joining a forward bladed ring (94) to a forward disk (96) to produce a forward turbine rotor (50), fabricating (178) an aft turbine rotor (52), and disposing (180) the forward turbine rotor (50) and the aft turbine rotor (52) in an axially-abutting, rotationally-fixed relationship to produce the axially-split radial turbine (20).