Compressor Housing Appendix for Surge Margin and Noise Control
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Solution Overview
Problem
Compressors face limitations in pressure ratio at low mass flow rates due to surge limits and generate noise, particularly the 'whoosh' noise, which affects performance and customer satisfaction.
Innovation Solution
Incorporating a closed pipe appendix into the compressor housing inlet duct, which is inclined and positioned optimally to enhance fluid dynamics, increasing pressure ratios and reducing noise across various mass flow rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If compressor operates at low mass flow rates, then pressure ratio is limited by surge limit, but operating closer to surge may generate severe fluid dynamic instabilities and noise
Solution Approach 1:
A passive acoustic treatment element (appendix with closed pipe) is introduced as an intermediary component in the air intake duct. This element mediates between the incoming air flow and the compressor wheel, modifying the acoustic characteristics of the flow without requiring active control systems. The closed pipe acts as a resonator that targets specific noise frequencies, particularly the 'whoosh' noise generated near surge conditions, while maintaining adequate surge margin.
2Productivity
If compressor operates closer to surge limit, then operative portion of compressor map is enlarged, but severe fluid dynamic instabilities and whoosh noise occur
Solution Approach 1:
The acoustic treatment element converts the harmful 'whoosh' noise generated near surge conditions into a beneficial outcome. By using a passive resonator structure (closed pipe appendix), the harmful acoustic energy is absorbed and dissipated, transforming the noise problem into an opportunity for passive noise control. This allows the compressor to operate closer to the surge limit, enlarging the operative portion of the compressor map, while the harmful whoosh noise is simultaneously reduced through the acoustic damping effect of the closed pipe resonator.
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 solution enlarges the compressor map's operative portion, improving low-end torque and reducing noise, especially in the frequency range causing 'whoosh' noise, without compromising peak power performance.
Implementation Method 1
The fluid dynamic phenomenon induced by the proximal end of the closed pipe allows the achievement of higher pressure ratios at small mass flow rates
Implementation Method 2
The introduction of an appendix including a closed pipe and integrated into the compressor housing at its inlet has proven to be effective in enlarging the operative portion of the compressor map by shifting the surge limit towards smaller mass flow rates. The fluid dynamic phenomenon induced by the proximal end of the closed pipe allows the achievement of higher pressure ratios at small mass flow rates. A further advantage is the achievement of significant noise dampening at different mass flow rates, especially in the frequency range related to the 'whoosh' noise phenomenon
Data Source
AI summary
A compressor housing includes a compressor inlet duct and an inlet for a compressor wheel. The compressor inlet duct has a longitudinal axis and connects an air intake duct with the compressor wheel inlet. The compressor housing includes at least one appendix positioned between an upstream portion of the compressor inlet duct and the compressor wheel inlet. The appendix includes a pipe closed in a distal part thereof with respect to the longitudinal axis of the compressor inlet duct.