Gas Turbine Outer Diffuser Case Structural Optimization
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Solution Overview
Problem
The existing designs for outer diffuser cases in gas turbine engines face challenges in achieving a long useful life, being lightweight, and capable of withstanding internal pressures, temperatures, and airflow volumes while allowing for easy maintenance.
Innovation Solution
The design of an outer diffuser case with a conical housing and radially projecting flanges made of high-strength materials like Inconel 718, featuring a diverging angle and optimized thickness and diameter ranges to support surrounding components and withstand internal dynamics, while minimizing weight and maintenance costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer diffuser case is designed with sufficient structural strength to withstand internal pressures and temperatures, then reliability is improved, but weight increases
Solution Approach 1:
The patent applies parameter changes by optimizing the wall thickness of the outer diffuser case within a specific range (0.125 to 0.250 inches) to achieve the minimum required structural strength while minimizing weight. The conical geometry with specific diverging angles (2.0 to 5.0 degrees) is also optimized to balance structural integrity and weight reduction.
Solution Approach 2:
The patent specifies using high-strength materials such as Inconel 718 or Inconel 625 for the outer diffuser case. These nickel-based superalloys provide exceptional strength-to-weight ratios and resistance to high temperatures and pressures, allowing the case to maintain reliability while being lighter than conventional materials.
2Ease of repair
If the outer diffuser case is designed for easy removal and installation during maintenance, then ease of repair is improved, but structural strength may be compromised
Solution Approach 1:
The outer diffuser case is designed as a separable component that can be removed as a unit from the engine assembly. The case includes integrated flanges with bolt patterns that allow it to be detached and reattached without requiring disassembly of the case itself, enabling easy maintenance while maintaining structural integrity through the unified design.
Solution Approach 2:
The outer diffuser case incorporates multiple functions into a single component: it provides structural support, contains the diffuser section, supports surrounding components via integrated flanges, and includes mounting features for accessories. This multi-functionality reduces the number of separate parts while maintaining strength and ease of maintenance.
3Reliability
If the outer diffuser case is designed to support surrounding components, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent merges the outer diffuser case with integrated flanges and mounting structures into a single unified component. The forward flange, mid-flange, and aft flange are directly formed as part of the case, eliminating the need for separate support brackets or mounting structures, thereby reducing overall device complexity while maintaining component support capabilities.
Data Source
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AI summary
An outer diffuser case 88 of a diffuser case assembly 84 for use in a gas turbine engine 20 may have a housing 98 orientated about an engine axis A, a forward flange 100 projecting radially outward from the housing 98, a mid-flange 104 spaced axially aft of the forward flange 100 and projecting radially inward from the housing 98, and an aft flange 102 projecting radially outward from the housing 98. The mid flange 104 is spaced axially between the forward 100 and aft 102 flanges and is configured to detachably engage an inner diffuser case 90 of the case assembly 84. The forward flange 100 is configured to detachably engage a high pressure compressor 52 and the aft flange 102 is configured to detachably engage a high pressure turbine 54 of the engine 20.