Diffuser tube resonator for refrigerant compressors
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Solution Overview
Problem
Refrigerant compressors, particularly centrifugal compressors, experience noise issues due to flow perturbations and pressure waves in the diffuser, which are not effectively attenuated by existing technologies.
Innovation Solution
Incorporating a diffuser plate with a plurality of quarter wave tubes, each featuring a cylindrical blind hole extending radially from the second wall, to attenuate acoustic noise by acting as a resonator and reducing specific acoustic frequencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional diffuser is used in the centrifugal compressor, then the compressor can maintain simple structure and ease of manufacture, but acoustic noise levels increase due to unattenuated flow perturbations and pressure waves
Solution Approach 1:
The diffuser plate is segmented by incorporating multiple quarter wave tubes distributed across its surface. Each tube acts as an independent resonator element, collectively providing noise attenuation across different frequencies while maintaining the overall diffuser structure's integrity and function.
Solution Approach 2:
Quarter wave tubes serve as intermediary resonating elements between the noise source (flow perturbations) and the surrounding environment. These tubes capture and attenuate acoustic energy through resonance, acting as a mediator that reduces noise transmission without blocking the diffuser's primary fluid flow function.
2Object-affected harmful factors
If quarter wave tubes are added to the diffuser plate, then acoustic noise is attenuated through resonance, but the manufacturing complexity and precision requirements increase
Solution Approach 1:
The quarter wave tubes are designed with specific dimensional parameters (depth, diameter, spacing) that can be optimized to target particular noise frequencies. By adjusting these parameters, the resonant frequency of each tube can be tuned to match dominant noise frequencies from the impeller-diffuser interaction, maximizing attenuation effectiveness.
Solution Approach 2:
Different regions of the diffuser plate can feature quarter wave tubes with varying dimensions and depths tailored to local noise characteristics. This allows targeted noise attenuation in specific frequency ranges or directional patterns without requiring uniform high-precision manufacturing across the entire diffuser structure.
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
The implementation of quarter wave tubes in the diffuser plate significantly reduces acoustic noise levels within the refrigerant compressor, particularly in high-frequency ranges, thereby improving operational silence and efficiency.
Implementation Method 1
the plurality of quarter wave tubes includes: a first series of circumferentially spaced quarter wave tubes; and a second series of circumferentially spaced quarter wave tubes radially outward of the first series
Implementation Method 2
to attenuate acoustic noise by acting as a resonator and reducing specific acoustic frequencies
Data Source
AI summary
A refrigerant compressor includes an impeller rotatable about an axis and a volute. A diffuser is axially between a first wall and a second wall, and radially between an outlet of the impeller and the volute. A diffuser plate provides the second wall, which includes a plurality of quarter wave tubes, each of the plurality of quarter wave tubes including a cylindrical blind hole extending radially from the second wall.