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Anyone here good with fluid mechanics? Muffler Q:

Discussion in 'Modifications and Projects' started by AndyJ, Aug 9, 2007.

  1. I'm wanting to weld up a muffler.

    This might sound strange, but i'd like to know:

    What would happen if you had a wide(ish) 90deg bend in the perforated section of the muffler? would this prevent it from distorting/absorbing the sound waves sufficiently?


  2. I'd warrant an educated guess that it wouldn't be a good thing! Any fluid has inertia and as such will resist a change of direction. If your attempting to change the direction of the fluid (in this case exhaust gases) and are doing that with a permeable membrane then your only going to be changing the direction of 'most' of the fluid not all of it. This is going to result in increased back pressure due to turbulence in the bend.
  3. You get pressure drop across any sort of bend. Obviously the larger the radius and the smaller the angle the less loss you get.

    As to acoustics, it would undoubtedly cut noise dramatically compared to a straight through system.

    What you would have to be careful of would be designing in a negative pressure wave that effected the gas flow adversely. given a large enough radius and smooth transitions this shouldn't be too hard to avoid.

    So yes, provided the above was observed and the pipe diameter was generous enough that the pressure drop (due to bend) was no less than a straight through system, the above design could significantly cut noise without adversely effecting performance.

    Well considered mate.