Split Compressor Casings with Porous Thermal Breaks
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Solution Overview
Problem
Conventional gas turbine engine casings, particularly split case designs, face issues with increased parts and assembly time, poor clearances, and leakage at the split joint, which are undesirable especially in downstream compressor stages that experience higher temperatures.
Innovation Solution
A compressor assembly with a split casing design featuring integrally formed monolithic case segments that include porous structures and cooling channels, manufactured using additive manufacturing to reduce thermal gradients and improve thermal management, allowing for reduced thermal conductivity and efficient cooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional split case design is used, then assembly is simpler compared to ring case, but clearances are poorer and leakage occurs at the split joint
Solution Approach 1:
The compressor case is divided into multiple segments (forward case segment and aft case segment) that can be assembled separately, maintaining the ease of manufacture benefit while using precision features at the split joint to control clearances and prevent leakage
Solution Approach 2:
The split joint area is given special attention with precision machining features, sealing surfaces, and alignment features localized at the joint to ensure proper clearance control and prevent leakage, while other areas of the case maintain their segmented structure for ease of assembly
2Manufacturing precision
If an annular ring case is used, then clearances and leakage control are improved, but the number of parts and assembly time increase
Solution Approach 1:
The case is segmented into manageable sections that can be manufactured and assembled separately, reducing the complexity of handling large single-piece ring cases while maintaining the precision features needed for clearance control
Solution Approach 2:
Multiple functional features (cooling channels, thermal breaks, structural support, and sealing surfaces) are merged into the segmented case design, allowing precision clearance control without requiring a complete single-piece ring case structure
3Use of energy by stationary object
If conventional cooling methods are used, then cooling is provided, but thermal gradients remain high requiring more cooling flow
Solution Approach 1:
A porous thermal break structure is inserted into the case to disrupt heat transfer paths, reducing thermal gradients and allowing more efficient cooling with reduced cooling flow requirements
Solution Approach 2:
The porous thermal break acts as an intermediary element between hot and cold regions of the case, mediating heat transfer to reduce thermal gradients and improve cooling efficiency
4Temperature
If additive manufacturing is used to form case segments, then thermal gradients are reduced and cooling is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process transitions to additive manufacturing with specific parameters (layer thickness, infill density, material selection) optimized to create the porous thermal break structure and cooling channels, achieving thermal gradient reduction through controlled manufacturing parameters
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 thermal gradients and maintains clearance gaps between compressor blades and casings, enhancing thermal management and reducing cooling requirements, while simplifying assembly and reducing part count and material variability.
Implementation Method 1
a first porous structure defined between the first inner structure and the first outer structure
Implementation Method 2
directing a fluid flow along a first axial channel; directing the fluid flow through a forward cooling cavity; directing the fluid flow along a second axial channel; and directing the fluid flow through an aft cooling cavity
Data Source
AI summary
Structures, such as compressor casings, for reducing a thermal gradient are provided. For example, a compressor case is split such that it includes first and second case segments. The first case segment extends over a first portion of the compressor case circumference and comprises a first inner structure, a first outer structure, and a first porous structure integrally formed as a monolithic component. The first porous structure is defined between the first inner structure and the first outer structure. The second case segment extends over a second portion of the compressor case circumference and comprises a second inner structure, a second outer structure, and a second porous structure integrally formed as a monolithic component. The second porous structure is defined between the second inner structure and the second outer structure. Methods of cooling structures such as compressor casings also are provided.