The　noise　pollution　in　pipelines　exists　for　a　long　time　and　can＇t　be　ignored　in　modern　industries.　It　is　important　to　investigate　the　transfer　mechanism　of　sound　energy　in　pipelines　and　develop　high　efficiency　mufflers　with　low　penalty　of　pressure　drop.　Different　with　the　traditional　method,　this　study　is　focused　on　the　flow　and　sound　fields　synergy　principle　to　investigate　the　flow　noise　propagation　mechanism　in　reactive　mufflers.　In　this　study,　theoretical　analysis　and　numerical　simulation　methods　are　coupled　to　investigate　the　noise　propagation　process.　In　the　theoretical　analysis　aspect,　the　synergetic　relationships　between　the　flow　and　pressure　gradient　fields　are　deduced　and　the　field　synergy　theory　is　established.　In　the　numerical　simulation　aspect,　the　flow　noise　propagation　process　in　the　simple　expansion　chamber　mufflers　is　studied.　The　results　show　that　with　the　decrease　of　synergy　between　flow　and　sound　fields,　the　work　done　by　the　fluid　on　the　wall　decreases,　which　means　the　exchange　of　sound　energy　between　the　wall　and　the　fluid　decreases.　©　2017　The　Author(s).