Abstract
Keywords :
Subsonic centrifugal compressor, analytical tool, acoustic sources, propagation modelling, mode matching techniques
Abstract
Centrifugal compressors are used for air conditioning applications in most of the transport systems. The acoustic disturbance mostly consists in tonal noise at the blade passing frequency and its harmonics. The estimation of noise from unsteady CFD calculations is not compatible with the development process of the compressor. Alternative methods are needed, in order to estimate in a short time schedule the radiated noise at the early stage of the design. An analytical software is developed to carry out noise calculation.
Two source mechanisms are considered :
• the interaction of the impeller wake flow with the diffuser blade, at the outlet of the impeller,
• the interaction of the flow distortion with the inlet of the impeller.
The modelling work has been separated in several elementary tasks dealing with :
- the modelling of the noise sources
- the analytical modelling of the propagation inside the different parts of the compressor
- the coupling of the source models and the propagation models (using mode matching techniques).
Preliminary results are given for the first two tasks and the task chaining is still in progress.