Back pressure question for fixed RPM engine

[motorambler]

We have a 125kWe natural gas generator set (having a 8.3L 1800 rpm turbocharged engine). The genset is housed in its oem enclosure w/internal silencer and has the vertically oriented tailpipe w/rain-cap just clearing the enclosure roof (nothing esoteric, just standard stuff). Anyway, our client wishes to extend the tailpipe section (after the silencer) by about 6 feet. Will this be ok? I don't know if back pressure will be adversely affected or not on a fixed rpm engine.

Thoughts?

 

[mattsooty]

If it is downstream of the muffler it is unlikely to have an appreciable downside.

MS

 

[RossABQ]

From a backpressure perspective, an easy thing to do. From a support perspective, not so much. I once did about the same thing, on about the same sized unit, and the support system for the additional exhaust pipe was the biggest cost and actually required a separate support structure. The genset mfr. wouldn't allow any new loads on the enclosure, insisted on a flex joint to prevent any loads on the existing exhaust system, on and on. Thermal growth is considerable and support has to be maintained. As I recall we also had to add a drip leg for condensation.

 

[TheBlacksmith]

From a backpressure standpoint 6 feet isn't too back. I have seen installations with 10 or more times that much extension and it did affect performance.

 

[GregLocock]

You can work out the increase in back pressure by considering the flow rate and pipe size. the engine manufacturer should be able to tell you.

Cheers

Greg Locock


New here? Try reading these, they might help FAQ731-376

http://eng-tips.com/market.cfm?

 

[motorambler]

Thanks very much to all for your feedback. We got it licked