Cold Spray Reinforced Impeller Shroud for Centrifugal Compressors
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Solution Overview
Problem
Shrouded impellers in centrifugal compressors face mechanical stress due to centrifugal forces at high peripheral speeds, limiting their efficiency and maximum power density, and are prone to deformation, making them unsuitable for extreme industrial applications.
Innovation Solution
The method employs cold spray additive manufacturing to deposit multiple layers of specific materials on the impeller hub and shroud, optimizing cohesion and modifying local natural frequencies to reduce stress and enhance performance, allowing higher peripheral speeds without structural issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If shrouded impellers are used to reduce leakage and improve efficiency, then efficiency is improved, but mechanical stress increases limiting maximum peripheral speed
Solution Approach 1:
The patent applies cold spray additive manufacturing to deposit material layers on the shroud, fundamentally changing the manufacturing parameters and material structure. This creates a porous, gradient-structured shroud that reduces mass while maintaining strength, thereby reducing centrifugal forces and mechanical stress at high peripheral speeds while preserving the seal function.
Solution Approach 2:
The patent uses composite material structure created by cold spray additive manufacturing, where layers of material are deposited to form a porous structure with gradient density. This composite structure provides both the sealing function to prevent leakage and the reduced mass needed to withstand high peripheral speeds with lower mechanical stress.
2Speed
If shroud mass is reduced to lower centrifugal forces, then peripheral speed capability is improved, but structural strength may be compromised
Solution Approach 1:
The patent employs porous materials created through cold spray additive manufacturing to construct the shroud. The porous structure reduces the overall mass of the shroud, thereby reducing centrifugal forces at high rotational speeds, while the controlled porosity and gradient structure maintain sufficient structural strength to prevent deformation and failure.
Solution Approach 2:
The patent implements local quality variations through gradient-structured material deposition on the shroud. Different regions of the shroud have different material densities and pore structures, with higher density in high-stress areas and lower density in low-stress areas. This optimizes the strength-to-weight ratio, enabling the shroud to withstand high peripheral speeds without compromising structural integrity.
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 approach enables shrouded impellers to withstand high centrifugal forces, achieving efficiency and power density comparable to unshrouded impellers while minimizing mechanical stress and deformation, thus suitable for demanding industrial applications.
Implementation Method 1
The method comprises depositing, on the shroud of a pre-machined impeller base material, additional material by cold spray additive manufacturing
Implementation Method 2
cold spray additive manufacturing produces oxide-free deposits and has proved better in retaining the original properties of the raw material to process without damaging it during manufacturing
Data Source
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AI summary
Shrouded impeller for centrifugal compressors and method for the manufacturing of shrouded impellers for centrifugal compressors comprising the steps of manufacturing an impeller base, then depositing by cold spraying at least one layer of metallic material on the surface of the frontal part of the impeller corresponding to the shroud of the impeller and machining the impeller to complete and finish the structure thereof. The at least one layer deposited by cold spraying may include grooves adapted to optimize the dynamic behavior of the impeller by modifying and tuning the local natural frequencies.