Разработка и оценка эффективности глушителя шума газовыхлопной системы подвесного лодочного мотора SEA PRO 2.5

Abstract

The article presents the results of developing and evaluating the effectiveness of the silencer of outboard motor SEA PRO 2.5 made in China. The experiments were carried out in a large experimental pool of Astrakhan State Technical University, with the use of a noise meter-spectrum analyzer Ecophysics-110 of the first class, with the software Signal+3G Light. In the theoretical analysis of the development, it has been suggested that the efficiency of silencers of exhaust systems of outboard motors could have a smaller effect than with cars, since at underwater exhaust the noise reduction will occur from the water layer when the motor is submerged. It has been proved that using a silencer in underwater exhaust systems of outboard motors can increase the aerodynamic drag for gases and reduce power. To test the theoretical assumptions, there was made a silencer for the gas exhaust system of the outboard motor SEA PRO 2.5 from stainless steel perforated sponge. It was determined that the net effect of the silencer (excluding water silencing) could be heard at low frequencies (up to 125 Hz) and makes up to 12.7 dba at full speed of the motor. The average equivalent sound level is reduced up to 4.5 dba at low speed, and at full speed of the outboard motor is practically not evident. In addition, the outboard motor noise level was reduced by water and made at full speed up to 22 dba for frequencies over 2000 Hz; for average equivalent noise level it made 15 dba. The combination of noise reduction by water and by a silencer helps to reduce noise at low and high sound frequencies, which is a positive effect of the developed device.