Thermal Bridge Structure for High-Pressure Temperature Differentials
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Solution Overview
Problem
Turbomachines with large temperature differentials and high-pressure conditions require a thermal bridge that can withstand thermal stress and ensure sound containment and sealing of high-pressure gas between sections, as existing solutions like ceramic matrix composites do not adequately address structural integrity and sealing.
Innovation Solution
A thermal bridge with a cylindrical body featuring a middle region and flanges on either side, including conical fillets and counterbore recesses for fastener installation, which provides a passageway for gas flow while maintaining structural integrity and sealing under high-pressure conditions, using materials like nickel-based alloys for durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a ceramic matrix composite (CMC) bridge is used to connect cold and hot sections, then high temperature resistance is improved, but structural integrity and sealing capability under high pressure deteriorate
Solution Approach 1:
The patent employs a composite structure combining nickel-based alloy (Inconel 718) with stainless steel (316L or 17-4 PH) to achieve both high temperature resistance and mechanical strength. The nickel-based alloy provides thermal stability while the stainless steel flanges provide structural integrity for high-pressure sealing, resolving the contradiction between temperature resistance and reliability.
Solution Approach 2:
Different regions of the thermal bridge use different materials optimized for their specific functional requirements: the nickel-based alloy cylindrical body handles thermal exposure, while the stainless steel flanges handle mechanical loading and sealing. This local differentiation allows each region to excel at its primary function without compromising overall reliability.
2Temperature
If a separate casing part is added to connect cold compression section to hot turbine section, then temperature differential isolation is improved, but device complexity increases
Solution Approach 1:
The thermal bridge integrates multiple functions into a single component: it provides thermal isolation between sections, structural connection for high-pressure containment, and mounting interfaces for seals and fasteners. This merging approach achieves temperature differential isolation without proportionally increasing device complexity.
Solution Approach 2:
The thermal bridge serves multiple purposes simultaneously: thermal barrier, structural connector, seal mounting platform, and fastener interface. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving effective temperature isolation.
3Strength
If flanges with multiple holes are used for bolted connections, then structural integrity is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies precise geometric parameters for the holes and counterbore recesses in the flanges, optimizing the distribution and dimensions to achieve uniform stress distribution and reliable sealing. These controlled parameter changes ensure structural integrity while maintaining manufacturability through standardized features.
Solution Approach 2:
The flange structure is segmented into multiple holes rather than a single large opening, distributing the mechanical load across multiple fastener points. This segmentation enhances structural integrity by preventing stress concentration while the holes are manufactured using standard drilling and counterboring processes.
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 thermal bridge effectively reduces thermal stress and maintains the integrity of bolted connections, ensuring sound containment and sealing of high-pressure gas, enhancing the operating performance of turbomachines by managing differential thermal growth and pressure.
Implementation Method 1
The conical fillet reduces stress concentration, and the counterbore recesses accommodate fasteners that experience differential thermal growth between the cold-side region and hot-side region
Data Source
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AI summary
A thermal bridge (100) forms a connection between a cold side and a hot side that is capable of withstanding a large temperature differential while high-pressure gas (e.g., air) flows between the two sides within an internal passageway. A cold-side region (120) and hot-side region (130) of the thermal bridge (100) may each have a flange (121, 131) with a plurality of holes (126, 136). The cold-side region (120) may also include a conical fillet (124) with counterbore recesses (125) to provide access to each of the plurality of holes (126) from a low radial position.