Zhenghang silencer, silencer

Zhenghang muffler, muffler
The silencing principle of the muffler is to use the appropriate combination of cavity and tube to achieve two functions to silencing
One is to use the sudden change of pipe cross section (that is, the change of acoustic impedance) The sound waves propagating along the pipe are reflected back in the direction of the sound source, so that the sound energy is reflected back to the original place
The second is to use the reflection of several interfaces to make the first forward-propagating sound wave return to the origin, and It turns back and propagates forward again, and this point merges with the second forward-propagating sound wave that has not been reflected, and the two are equal in amplitude and an odd number of times different in phase, so they interfere with each other and cancel each other.