Compressor Wheel Blunt Shroud Edge Design
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Solution Overview
Problem
Compressor wheels in exhaust-gas turbochargers suffer damage from corrosive elements and particles in the exhaust gas, leading to erosion and reduced service life, with existing coatings like NiP not adequately addressing the issue without compromising fluid mechanics and thermodynamic characteristics.
Innovation Solution
The compressor wheel design features a blunt shroud-side end region for the blade leading edges, which improves robustness against droplet and particle impact while maintaining optimal fluid mechanical and thermodynamic performance, achieved by making the shroud-side end region of the blade leading edges semicircular or blunt, contrasting with the sharp or elliptical hub-side ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the compressor wheel blades are made thin and sharp-edged to achieve optimal fluid mechanics characteristics, then the fluid mechanical and thermodynamic characteristics are improved, but the robustness against droplet and particle impact deteriorates
Solution Approach 1:
The patent applies different geometric characteristics to different regions of the blade leading edge. The hub-side end region maintains a sharp or slightly elliptical shape for optimal fluid mechanics, while the shroud-side end region features a blunt shape with a radius of curvature of 0.5mm to 5mm for enhanced robustness against particle and droplet impact. This local differentiation resolves the contradiction by optimizing each region for its specific functional requirements.
2Reliability
If the compressor wheel blades are thickened to improve robustness against droplet and particle impact, then the robustness is improved, but the fluid mechanical and thermodynamic characteristics deteriorate
Solution Approach 1:
Instead of uniformly thickening the entire blade, the invention locally modifies only the shroud-side end region of the blade leading edge to have a blunt shape. This localized approach provides the necessary robustness against particle and droplet impact while preserving the thin, sharp geometry of the hub-side region, thereby maintaining optimal fluid mechanical and thermodynamic characteristics.
3Reliability
If a coating like NiP is applied to protect against corrosion and particle damage, then protection against corrosion and particle damage is improved, but the fluid mechanical characteristics may be compromised
Solution Approach 1:
The patent implements a geometric modification (blunt shroud-side end region) as a preliminary protective measure against particle and droplet impact before any coating is applied. This pre-protective geometric design reduces the susceptibility to damage, allowing for the use of thinner or more fluid-mechanically-compatible coatings while still achieving adequate protection against corrosion and particle damage.
Data Source
AI summary
A compressor wheel is provided for an exhaust-gas turbocharger of an internal combustion engine. The compressor wheel has a hub, which extends around a central axis of the compressor wheel, and compressor wheel blades, which are connected to the hub and the blade leading edges of which extend in a radial direction and have a hub-side end region and an end region that is radially remote from the hub. The blade leading edges are blunt in their end region that is radially remote from the hub.