In order to analyze the flow field characteristics of the split-stream rushing muffler, a theoretical model describing the velocity of the split streams is established
and verified by the tracer test. For this new-principle muffler, the acoustic performance and the relationship between the velocity drop of the airflow and the
pressure field are analyzed, also the structure optimization of the muffler is carried out based on the orthogonal test. Finally, a new muffler is fabricated based
on the designing theory of this type of muffler for a prototype of diesel engine,
and the comparative analyses are conducted compared with its original muffler.
The results show that the establishment and analysis of the theoretical model for
velocity during the split-streams rushing process are correct. In the frequency
range of 0–1000 Hz, the average transmission loss of split-stream rushing muffler
is better than that of the original muffler. While the speed of airflow is reduced by
split-streams rushing, a certain pressure loss is caused at the same time, which is
about 50% of total pressure loss of the muffler, and the average fluid resistance
coefficient of the split-stream rushing process is 0.91. Compared to the original
muffler of the sample engine, the average insertion loss of the optimized new muffler is increased by 61.2%. At inlet air velocity of 30 m/s, the pressure loss is reduced
by 16.8%. The results provide a potential for practical engineering application of
this new split-stream rushing muffler in future. © 2020 Institute of Noise Control
Engineering