Protected Impeller Leading Edges for Compressor Erosion Resistance
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Solution Overview
Problem
Centrifugal compressors face erosion issues due to solid particles and liquid droplets, with existing solutions like filters and erosion-resistant materials compromising on mechanical properties, and requiring costly maintenance.
Innovation Solution
The integration of protection elements made from cobalt, nickel, titanium, or martensitic stainless steel alloys, permanently attached to the impeller's blades and shroud, providing targeted erosion resistance without affecting the main body's mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If erosion-resistant materials are used for the impeller, then erosion resistance is improved, but mechanical properties deteriorate
Solution Approach 1:
The patent applies different materials to different parts of the impeller: the main body uses material optimized for mechanical properties while the leading edges use material optimized for erosion resistance. This local differentiation resolves the contradiction by allowing each region to have the material properties best suited for its specific functional requirements.
Solution Approach 2:
The patent uses composite construction where the impeller combines a base material (e.g., aluminum alloy) with erosion-resistant coating or overlay materials (e.g., stellite, carbide coatings) on the leading edges. This composite approach enables simultaneous achievement of both mechanical strength and erosion resistance.
2Reliability
If filters and separators are installed at the inlet, then erosion is reduced, but device complexity and cost increase
Solution Approach 1:
The patent extracts the erosion protection function from the main impeller body and concentrates it on the leading edges through specialized materials or coatings. This eliminates the need for separate filters and separators, reducing system complexity while maintaining erosion protection.
Solution Approach 2:
The impeller's leading edges are equipped with erosion-resistant materials that provide self-protection against particle impact. This self-service approach eliminates the need for external protection devices like filters, simplifying the overall system.
Data Source
AI summary
The impeller includes a main body with a root, a shroud and a plurality of blades connecting the root and the shroud. Protection elements are associated to the blades and constitute at least the front part of the blades. The protection elements may consist of separate bodies or may be grouped together to form one or more protection bodies. In an embodiment, the material of the protection elements is different from the material of the main body, and may be, for example, a cobalt base alloy having a chromium content greater than 20% or nickel base alloy having a chromium content greater than 12%.