抄録
Equipment of sound absorbers mid-air in the duct is an effective countermeasure for anti acoustic resonance in tube bundles of heat exchangers. Its design method, including the number or placement of absorbers in the duct space for efficient performance, was developed based on acoustic FEM. Here, the acoustic characteristics of absorbers, such as effective bulk modulus, loss factor or density of the air within the absorbers are needed. These parameters are evaluated by flow resistance method or impedance tube method. Complex eigenvalue analysis with acoustic FEM is executed which yields the increase of modal damping ratio by the equipment of absorbers. In order to verify the above-mentioned method, the acoustic experiment with the scale model of coal-fired boilers was conducted and experimental and analytical results are in good agreement. Finally this method was applied to the actual boiler plant and based on these results, it was confirmed that the proposed method is the effective countermeasure for the and acoustic resonance in heat exchangers.
