Noise silencing technology for manifold flow noise based on ANSYS fluent

•The SPL of manifolds can be as high as 110 dB, which can easily cause mental damage and should be urgently addressed.•To controlling the impact damage caused by the medium will effectively reducing the impact noise inside the manifold.•A type of small-hole muffler was designed to address the excessive flow noise of manifolds.

Fluid dynamic noise, namely, flow noise, produced by eddy disturbances and friction along the pipe walls becomes a significant problem in a natural gas transmission and distribution station. The Sound Pressure Level (SPL) distribution of the manifold flow noise is studied based on a theoretical method that combines large eddy simulations with the Ffowcs Williams–Hawkings (FW–H) acoustic analogy theory. The results shows that decreased with the inlet pipe diameter, the acoustic energy and the SPL of the flow noise at the end of the inlet pipe gradually increased. A small-hole muffler is designed and installed to address the manifold flow noise, and their noise reduction effects are subsequently analyzed. The results show that the small-hole muffler effectively reduced low-frequency noise up to 37.4 dB, and the mean noise reduction is about 20.9 dB.