Development of Micropore Mufflers

Research on micropore mufflers was started in the middle of the 1970s. In this article we have summarized and systematized what has been done in the past 20 years. Some expressions, derivations, and calculation curves have been formally modified to make them easier to understand and apply. Some new considerations have been added. The main purpose of this article is to introduce the fundamentals, theories, and calculations that are useful for the design of a micropore muffler. Therefore, we have not included any experiments. Direct and indirect experimental proofs can be found in the given relevant references. Micropore mufflers are grouped into two classes, simple micropore mufflers and expansion micropore mufflers. The latter have additional noise reduction due to flow expansion. Noise reduction and flow are two important aspects that have been discussed in detail.