Protected Impeller Structure for Centrifugal Compressor Erosion
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Solution Overview
Problem
Centrifugal compressors face erosion issues, particularly from liquid droplets, which existing solutions like filters and erosion-resistant materials compromise on mechanical properties, and are costly and bulky.
Innovation Solution
The implementation of protection elements made from materials like cobalt base alloy, nickel base alloy, titanium base alloy, and precipitation hardening stainless steel, permanently attached to the front part of the impeller blades, shroud, and root, providing enhanced erosion resistance without compromising mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If filters and separators are used to reduce erosion, then erosion resistance is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the erosion protection function from separate filters and separators and integrates it directly into the impeller blades through protection elements. These protection elements are permanently arranged on the front side of the impeller blades, allowing the impeller itself to serve as the erosion barrier, thereby eliminating the need for additional filter components.
Solution Approach 2:
The protection elements act as an intermediary between the impeller blades and the erosive particles/droplets. Made from erosion-resistant materials, these elements absorb the impact damage that would otherwise affect the main impeller structure, serving as a sacrificial protective layer.
2Reliability
If erosion-resistant materials are used for the impeller, then erosion resistance is improved, but mechanical properties deteriorate
Solution Approach 1:
The patent applies local quality by using different materials for different parts of the impeller. The main impeller body is made from material optimized for mechanical strength, while only the front portions of the blades (where erosion occurs) are covered with erosion-resistant protection elements. This localized application of erosion resistance avoids the need to compromise the entire impeller's mechanical properties.
Solution Approach 2:
The impeller becomes a composite structure combining two material systems: the base impeller material providing mechanical strength and the protection element materials (such as cobalt base alloy, nickel base alloy, titanium base alloy, or stainless steel) providing erosion resistance. This composite approach allows each material to perform its optimal function.
3Reliability
If protection elements are permanently arranged on the impeller, then erosion resistance is improved, but manufacturing complexity increases
Solution Approach 1:
The protection elements are designed as separate, segmented components that can be manufactured independently from the main impeller body. This segmentation allows for specialized manufacturing processes for the protection elements (such as additive manufacturing or precision casting) while keeping the main impeller manufacturing simple. The elements are then attached to the impeller blades through various joining methods.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively protects the impeller from liquid droplet erosion, allowing the use of different materials for the main body and protection elements, reducing the need for filters and separators, and ensuring a long lifetime of the impeller by withstanding impacts and fluid flow.
Implementation Method 1
protection elements made of a cobalt base alloy, a nickel base alloy, a titanium base alloy, a precipitation hardening stainless steel, a martensitic stainless steel... protecting the impeller from e.g. liquid droplets erosion... withstand the impacts of solid particles and/or liquid droplets
Data Source
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AI summary
The impeller comprises a main body with a root (1), a shroud (2) and a plurality of blades (3) connecting the root and the shroud; protection elements (10) are associated to the blades (3) and constitute at least the front part of the blades (3); the protection elements (10) may consist of separate bodies or may be grouped together to form one or more protection bodies; advantageously, 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%.