Measurement and modelling techniques to approach the problem of noise reduction of domestic range hood

The noise level of domestic range hood is one of the major causes of the product perceived quality. The market actually requires increasing of flow rates and low noise levels. Both the goals are difficult to obtain. Noise in range hoods comes from vibrations generated by the rotating components of the fan (electric motor and impeller unbalances, periodic excitation of magnetic forces, etc.) and from the air flows in the rotating and stationary ducts. A combined experimental and theoretical methodology is proposed to approach the problem of noise reduction of range hoods. The experimental approach is based on the use of simple microphones and accelerometers to have a quick characterization of the noise spectrum and vibration characteristics of different models of range hoods. The second phase is based on the theoretical modelling of the structural vibrations and flows by FEM and CFD codes in order to better understand and identify the reasons of the main noise sources. Once identified the main problems some work prototypes of range hood components with and without the noise source identified has been realized and the possibility of noise reduction quantified by intensity measurement techniques.