A Study on Characteristics of Noise Radiated from Mufflers with Air Flow (1st Report)

気流を伴う消音器の放射騒音特性に関する研究 (第 1 報)

A Study on Characteristics of Noise Radiated from Mufflers with Air Flow (1st Report)

Creators Izumi Haruo

Creators Kojima Naoya

Creators Fukuda Motokazu

This paper presents an experimental study on generation machanism and reduction methods of air flow noise in cavity type mufflers. The effects of various flow speed, cavity lengths, cavity diameters were examined, clarifying the frequency characteristics of that noise. The visualization of internal flow and the measurement of local velocity in the muffler were performed using the smoke-wire method, and hot-wire velocimeter. From these experiments, the distribusion of mean velocity and the turbulence characteristics of the internal flow were able to be clearly shown for each type of muffler. It was also clarified that a great deal air flow noise is generated when a jet stream from the inlet pipe directly impacts the tail pipe. entrance Then, the effects of various methods for the reduction of impact energy and air flow noise are systematically studied.

[ISSN]0372-7661

[NCID]AN00244228