60-61 Performance evaluation of lined duct bends -Experiment vs. theory

Ramani Ramakrishnan, Romain Dumoulin


Acoustical performances of simple elbow silencers, used in building HVAC systems, have been conventionally evaluated using empirical relations based on laboratory and/or field measurements. The current investigation has made use of COMSOL, a powerful multiphvsics numerical analysis tool and has attempted to provide results based on multi-dimensional analysis. The acoustic propagation in the liner material uses the complex propagation constant and complex density of bulk reacting material. A given acoustic field was assumed at the inlet of the elbow and the outlet is connected to a long anechoic termination. To accommodate high frequency calculation, COMSOL suggests using a length of pipe in front of the elbow within which scattered acoustic field is calculated to provide the required acoustic field at the inlet of the lined (or unlined) elbow.


Acoustic spectroscopy; Climate control; Numerical analysis; Acoustic propagation; Acoustical performance; Empirical relations; Field measurement; High frequency; HVAC system; In-buildings; Lined ducts; Liner material; Performance evaluation; Propagation constant

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