Angled Inlet Guide Vane Assembly With Conforming Shroud Plug Sealing
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Solution Overview
Problem
Gas turbine engines face issues with airflow non-uniformity due to the long and heavy vane inlet structure, which allows air ingestion and creates undesirable flow through the interface between the inlet case and rotor shroud, complicating the gas path.
Innovation Solution
A variable inlet guide vane assembly with an elliptically shaped vane inlet at an acute angle and a conforming shroud plug, featuring a teardrop design with packing gaskets and fasteners, which seals the interface and prevents air ingestion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the vane inlet is made long enough to allow the vane airfoil to pass, then the vane can be properly installed, but the inlet case becomes relatively long and heavy
Solution Approach 1:
The inlet case is divided into a front section and a rear section by introducing a shroud plug that closes the vane inlet aperture. This segmentation allows the inlet case to be shorter while still providing sufficient length for vane installation, as the shroud plug effectively extends the functional length of the inlet path without adding to the physical length or weight of the inlet case structure.
2Ease of manufacture
If the vane inlet aperture is aligned with the engine centerline, then assembly is simplified, but air ingestion at the interface creates undesirable non-uniform flow
Solution Approach 1:
A shroud plug is introduced as an intermediary component that closes the vane inlet aperture and prevents air ingestion at the interface between the inlet case and rotor shroud. This intermediary element eliminates the harmful airflow path while maintaining the simple centerline-aligned aperture configuration, thus preserving assembly simplicity while removing the flow uniformity problem.
3Ease of manufacture
If a standard circular shroud plug is used, then manufacturing is easier, but it does not conform to the elliptical vane inlet shape creating gaps
Solution Approach 1:
The shroud plug is designed with an elliptical cross-section that matches the specific geometry of the vane inlet aperture. This local adaptation of the plug shape to the aperture geometry ensures complete sealing and eliminates gaps at the interface, while the elliptical shape itself remains relatively simple to manufacture using standard machining processes.
Data Source
Figure 1
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Figure 4
AI summary
An inlet guide vane assembly (120) of a gas turbine engine (20), the assembly (120) having an inlet case (110) having an outer ring (240) that extends axially along an engine axis (A) between a ring front end (250) and a ring aft end (260), and radially between a ring outer surface (270) and a ring inner surface (280), wherein: the outer ring (240) has a vane inlet (290), defined by a vane inlet surface (295) that extends between the ring outer and inner surfaces (270, 280); the vane inlet (290) that is elliptically shaped having an inlet long axis (LA1) disposed at an acute angle to the engine axis (A); and the assembly (120) includes a shroud plug (330), the shroud plug (330) having an inner portion (360) that is disposed within the vane inlet (290), the inner portion (360) having a shape that conforms with the vane inlet (290).