APU Compressor Impeller Splitter Blade Resonance Control
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Solution Overview
Problem
The compressor blades in auxiliary power unit (APU) gas turbine engines are prone to resonance frequencies due to flow and rotational forces, leading to potential degradation and reduced lifespan.
Innovation Solution
The design incorporates a hub with splitter blades interposed between main blades, featuring contoured surfaces defined by specific Cartesian coordinates, with a contour between the tip and leading edge at an angle between 35 and 65 degrees, reducing resonance excitation and fatigue stresses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional compressor blades are used in APU, then the structure is simple and easy to manufacture, but the blades are prone to resonance frequencies and fatigue stresses that reduce lifespan
Solution Approach 1:
The blade is divided into multiple segments including main blades and splitter blades. The splitter blades are positioned between the main blades to break up the continuous blade structure, thereby reducing resonance frequencies and fatigue stresses while maintaining structural integrity and performance
Solution Approach 2:
The blade design incorporates varying local properties through different blade configurations. The splitter blades have specific contour definitions and positioning that differ from main blades, creating localized structural variations that reduce resonance and fatigue in critical areas without compromising overall blade function
2Reliability
If blade contours are optimized to reduce resonance, then blade lifespan is extended, but manufacturing precision requirements increase
Solution Approach 1:
The blade contours are pre-defined using coordinate systems and mathematical definitions before manufacturing. The splitter blade contours are specifically designed with predetermined geometric parameters and positioning relative to main blades, allowing for precise reproduction during manufacturing while reducing resonance and fatigue stresses
Data Source
AI summary
A compressor impeller for an Auxiliary Power Unit (APU) includes a hub including a plurality of splitter blades interposed between a plurality of main blades. Each of the plurality of splitter blades and the plurality of main blades include a first surface and a second surface. The first surface and the second surface of the plurality of splitter blades are defined as a set of X-coordinates, Y-coordinates and Z-coordinates set out in Table S-1 and S-2 scaled by a desired factor. The X-coordinate being in an axial direction, the Y-coordinate being in a first radial direction and the Z-coordinate being in a second radial direction transverse to the first radial direction. Each of the plurality of splitter blades includes a contour between the tip and the leading edge. An auxiliary power unit and method are also disclosed.