本文阐述了柴油机水下排气噪音的形成过程,指出影响排气管口辐射噪音的主要因素是气体在尾管出口的平均流速、流速变化幅值和频率。当排气管内存在强噪音时,不宜忽视管壁的辐射噪音。为有效地降低柴油机水下排气噪音,在排气系统中安装排气冷却消音器应综合考虑上述因素。文中给出了柴油机排气冷却消音器结构设想和靠发动机安装的结论。 This paper describes the formation process of underwater exhaust noise of diesel engine. It is pointed out that the main factor affecting the radiation noise of exhaust nozzle is the average flow velocity, amplitude and frequency of gas flow at the exit of tail pipe. When there is strong noise in the exhaust pipe, it is not advisable to ignore the radiation noise of the pipe wall. In order to effectively reduce the underwater exhaust noise of diesel engines, the installation of exhaust cooling silencers in the exhaust system should take all these factors into consideration. The paper gives the structure of diesel engine exhaust cooling muffler design and conclusions by the engine installation.