Centrifugal Compressor Impeller Vane Thickness Variation
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Solution Overview
Problem
Centrifugal compressor impellers face stress concentration issues near the hub, which can reduce their lifespan, and traditional methods to address this, such as oversizing, negatively impact aerodynamic properties.
Innovation Solution
The impeller design features a chordwise reduction in vane thickness, with the trailing edge thickness between 65% and 70% of the maximum, and a maximum thickness positioned upstream within the upstream half of the vane, reducing stress concentration and maintaining aerodynamic efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If vane bulk is increased to reduce stress concentration, then stress resistance is improved, but aerodynamic properties deteriorate
Solution Approach 1:
The patent applies local quality by varying the vane thickness along the chordwise direction. The vane has maximum thickness at the leading edge (40-60% of chord length) to provide stress resistance, while the thickness decreases toward the trailing edge (20-40% of maximum thickness) to maintain aerodynamic efficiency. This non-uniform thickness distribution allows different regions of the vane to have optimized properties for their specific functional requirements.
2Strength
If oversizing approach is used to address stress concentration, then stress resistance is improved, but device complexity increases
Solution Approach 1:
The patent employs parameter changes by modifying the vane thickness parameter along the chordwise direction. The thickness is defined as a function of position, with specific ranges given for different sections: maximum thickness at 40-60% chord position, and trailing edge thickness at 20-40% of maximum. This parametric approach allows stress resistance improvement through controlled thickness variation rather than uniform oversizing, simplifying the overall design while addressing stress concentration.
Data Source
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AI summary
An impeller (22) for a centrifugal compressor (20) of a turbine engine (10), the impeller (22) including a hub (30) defining a rotation axis (26) about which the impeller (22) is rotatable, and a vane (32, 32a) extending from the hub (30). The vane (32, 32a) has a leading edge (56), a trailing edge (58), and a chord (60) defined therebetween, a pressure side (52) of the vane (32a, 32) and a suction side (54) of the vane (32a, 32) opposite the pressure side (52). A vane thickness is defined transversely between the pressure side (52) and the suction side (54), the vane thickness reducing over at least a downstream 40% of the chord (60). The vane thickness has a trailing edge thickness (58a) value at the trailing edge (58) of between 40% and 80% of a maximum thickness value (78) of the vane thickness.