Abstract
A premixed-combustion type boiler with a multi-port burner plate has a strong tendency of extremely loud noise in the frequency range determined by the geometric structure of boiler system. Therefore, it is necessary to propose a noise reduction method for this type of boiler. In this paper, the passive reduction method using a cylindrical muffler with sliding stopper is proposed, considering the fact that the frequency spectrum of combustion driven oscillation noise has a peak level, that is similar to acoustic resonance of pipe. In this paper, at first, basic features of oscillation noise are made clear, and then noise reduction effect of proposed muffler, and its features and optimal parameters for its use are experimentally examined. Experimental results show that using the proposed muffler has a striking effect on noise reduction and the sound level can be lowered to the ground noise level by about 40dB at most.
