Shroud Resonators for Fluid Machine Noise Reduction
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Solution Overview
Problem
Fluid machines, such as compressors and pumps, face challenges in reducing noise generation while maintaining superior aerodynamics performance due to the high pressure generated between the impeller and the shroud, with existing noise reduction methods often resulting in increased aerodynamic loss.
Innovation Solution
The implementation of resonators within the flow passage of the shroud, arranged with varying densities and positions to guide fluid flow and reduce noise, while minimizing aerodynamic loss by forming a concave flow passage and hollow spaces that correspond to the blades, effectively addressing the noise and performance issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a separate apparatus is installed on the impeller or the shroud to reduce noise, then noise reduction is achieved, but aerodynamic loss increases
Solution Approach 1:
The noise reduction function is merged with the shroud structure by integrating resonators directly into the shroud's flow passage. This combines the aerodynamic function of the shroud with the noise reduction function of the resonators, eliminating the need for separate noise reduction apparatus that would cause aerodynamic loss.
Solution Approach 2:
The resonators act as an intermediary element within the flow passage, mediating between the high-pressure fluid and the shroud structure. They absorb pressure-induced vibrations and convert acoustic energy, reducing noise transmission while maintaining fluid flow paths.
2Object-affected harmful factors
If a groove is formed on a casing wall to reduce vibration, then vibration reduction is achieved, but aerodynamic loss increases seriously
Solution Approach 1:
Instead of forming grooves that disrupt the overall flow field, the resonators are strategically positioned at specific locations within the flow passage where pressure-induced vibrations occur. This local intervention reduces vibration without creating widespread aerodynamic disruption.
Solution Approach 2:
The resonators utilize mechanical vibration principles by being designed to resonate at specific frequencies matching the noise-generating vibrations from the impeller-shroud interaction. This allows them to absorb and dissipate vibrational energy effectively.
3Object-affected harmful factors
If a hole is formed in a shroud to reduce noise, then noise reduction is achieved, but aerodynamic loss increases
Solution Approach 1:
The resonators are nested within the shroud structure, with their openings facing the flow passage and their hollow spaces positioned within the shroud material. This nested configuration allows noise reduction functionality to be embedded within the existing shroud geometry without disrupting external flow patterns.
4Object-affected harmful factors
If resonators are arranged in the flow passage, then noise reduction is achieved, but aerodynamic performance may be affected
Solution Approach 1:
The resonators are arranged with varying densities in different sections of the flow passage, applying noise reduction action partially where needed rather than uniformly throughout. This selective arrangement reduces noise in high-pressure zones while minimizing interference with overall aerodynamic performance.
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 reduces noise generation and maintains or improves aerodynamic performance by allowing smooth fluid flow and reducing pressure-induced noise between the impeller and shroud, without increasing aerodynamic loss.
Implementation Method 1
a fluid machine having resonators for reducing noise and simultaneously having improved aerodynamics performance
Data Source
AI summary
A fluid machine includes a rotatable hub; a plurality of blades spaced apart from one another along a circumferential direction with respect to a rotation center of the hub; and a shroud extending along a circumferential direction with respect to the rotation center of the hub and covering the plurality of blades. The shroud includes: a flow passage, the flow passage formed to be recessed with respect to an inner surface of the shroud facing the blades; and a plurality of resonators provided in the flow passage.