Acoustic Modelling and Low Frequency Control of Furnace Noise

The high temperature hot water heating system at the University of Calgary uses three similar Dominion Bridge furnaces. The acoustic radiation from their stacks shows several distinct frequency components from 4 to 80 Hz. In order to explore techniques to reduce the levels in the 30-60 Hz range, finite element modelling of these furnaces was developed. Once the model confirmed that these frequencies were a result of resonant behaviour, it was further used to design a stack silencer which would meet architectural as well as acoustic criteria. Evaluation of the silencer indicated that the reduction in overall level was close to that predicted by the finite element model.