Compressor Case Cooling Cavity for Blade Tip Clearance Control
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Solution Overview
Problem
Existing compressor cases for gas turbine engines face challenges in blade tip clearance control, requiring complex and costly manufacturing processes, and limited options for modifying the exterior to manage system response, while maintaining the ability to mount engine accessories.
Innovation Solution
A compressor case design featuring a cooling cavity with a vane stage and trunnion bearing, where the cavity walls are cast or welded as unitary members to form a U-shaped end channel, allowing for airflow to control temperature and optimize tip clearance, with a thinner cavity outer wall for minimal component interference and improved responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the wall thickness of the compressor case is adjusted to control blade tip clearance, then the system response speed is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The compressor case is segmented into multiple functional zones with different wall thicknesses. The case includes a forward annular portion, an aft annular portion, and a intermediate annular portion with varying thicknesses to optimize thermal response in different regions while maintaining manufacturability of each segment
Solution Approach 2:
Different regions of the compressor case are designed with locally optimized wall thicknesses. The forward annular portion has a first wall thickness, the intermediate portion has a second wall thickness, and the aft portion has a third wall thickness, allowing each region to respond appropriately to thermal conditions while maintaining overall structural integrity
2Device complexity
If the cavity outer wall is made thinner to reduce interference, then the component interference is minimized, but the structural strength may be compromised
Solution Approach 1:
The cavity outer wall is designed with locally optimized thickness. It is thinner than the forward and aft annular portion walls to minimize interference with adjacent components, while still maintaining sufficient structural strength through strategic placement and support from the thicker forward and aft portions
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 design enables active cooling or heating of the compressor case, enhancing blade tip clearance control and stability, and allows for more responsive system dynamics with minimal impact on external component mounting.
Implementation Method 1
a port, formed in the cavity outer wall, for directing an airflow into the cooling cavity
Implementation Method 2
blade tip clearance control in compressor cases, e.g., accounting for movement of the blade, may be controlled by adjusting a wall thickness of the case
Data Source
AI summary
A method of manufacturing a compressor. A member is cast having forward and aft annular portions. A cavity forward wall extends from the forward annular portion to a first inner end. A cavity aft wall extends from the aft annular portion to a second inner end. A cavity outer wall extends between the forward and aft annular portions and defines an outer aperture. A cavity inner wall is cast and welded between the cavity forward and aft walls such that the cavity inner wall is offset from the first and second inner ends of the cavity forward and aft walls to form a U-shaped end channel. The compressor case is capable of receiving a vane so that a trunnion bearing extends from a vane root to a trunnion bearing outer end, through the inner aperture in the cavity inner wall and the outer aperture in the cavity outer wall.