Attenuation for the Simple Expansion Chamber Muffler with a Right Angle Inlet

ABSTRACT The simple expansion chamber muffler is a base control device whose use is to attenuate sound power, and has been known for a long time. Some of the most compelling research has focused on the mufflers with a straight inlet and outlet. To date, a muffler with a right angle inlet has never been studied. Therefore, the purpose of this work is to analyze the simple expansion chamber muffler with a right angle inlet. The numerical results show a comparable agreement between the experiment and other numerical approaches. A discussion is also presented in this work on the muffler with a different radius to that of the inlet/outlet pipe, a different inlet part, etc. The result clearly shows that the attenuation of the muffler with a right angle inlet is better than that with a straight inlet at particular frequencies. In addition, the mufflers do not have any absorbent linings attached to the inside of them, unlike the right angle-inlets which do. However, the propagation of sound in the muffler with a right angle inlet can lead its sound power to be attenuated about 10 ∼ 40dB at those particular frequencies.