Exhaust Duct Engineer 1

[TugboatEng]

I have an upcoming project that requires an offset in some 16 inch pipe but don't have room for two 90° elbows. I believe this can be achieved using rectangular ducting but there are complications of very high vibration and rapid temperature cycling of up to 1000°F within minutes. What type of engineer specializes in this type of design? This one is way over my head. I don't know where to look.

 

[mfgenggear]

A nice 3 d model with actual size might help.
In the old days before computers, hand drawn prints, model shop would built it to make it fit. Then the designer would draw and spec it out. With correct material, and process.

 

[mfgenggear]

 

[mfgenggear]

Tug

Some good info for you important
Search on YouTube

Thermal diesel generator insulated modular
Exhaust for emergency generator.

Tafe power diesel generator installation process

This may help as well
De Angelo marine water cooled exhaust.

 

[TugboatEng]

Center to center is 48 inches.

Moving the bellows into the horizontal run is an option it would gain 14 inches of additional vertical clearance vertically. I can possibly swap positions of the SCR and muffler to get the SCR further from the engine to make room in the horizontal run for the bellows.

3D, I intended to use turning vanes. CFD would need to be performed which is not in my wheelhouse which is why I'm interested in hiring a consultant.

 

[mfgenggear]

Tug

Look at the previous post it would be helpful. Draw it out full size, to verify fit up.
Horizontal bellows may do the trick.
Mint was on to it.

 

[dvd]

I have worked with Airflow Sciences on several CFD projects. I think highly of them.

 

[3DDave]

COMSOL has a list of consultants.

 

[JStephen]

We occasionally use short-radius ells in similar sizes and I'm not aware of an issue getting them. We use standard weight carbon steel, and if you were looking for other alloys, that might be a problem. Flow resistance is higher than long radius (which in turn is higher than even-longer radius) but probably not any worse than the into-a-box-out-of-a-box idea, either.

 

[TugboatEng]

86 inH2O is my allowable back pressure

3DDave, I Googled COMSOL and see that they are a software company? It does look like their software is relevant.

 

[3DDave]

https://www.comsol.com/partners-consultants/certified-consultants

 

[dvd]

It is only 1 psi, make it out of 10 ga or even 7 ga 309ss maybe 11 gores for each of two 135 degree elbows. A good industrial sheet metal shop can knock that out. This sketch has a 14" c.l. radius.

 

[TugboatEng]

Thanks, 3D, it looks like they have consultants in my state which is best.

We are currently awaiting word from our engine manufacturer on the orientation of the exhaust outlet. I am preparing in case we get the incorrect coynfigurarion which is looking likely.

DVD you have just described a $100k welding job...

 

[dvd]

DVD you have just described a $100k welding job...

... don't forget to add material costs and overhead!

 

[TugboatEng]

My target is $30k for 2.

 

[mfgenggear]

Wow for that much you order a custom setup

 

[TugboatEng]

I would certainly like to do it for less. To buy the correct outlets for the engines is $60k so if I can rig together a solution for half I am off to a good start. The correct outlets are not available to purchase within our required timeframe.

 

[Tmoose]

Is there a plan view of the installation showing available space?

 

[mfgenggear]

Tug
sheet metal, tube, and pipe manufacture can whip some thing out if they can get material order from fry steel, they can get it over night.
If they are hungry for work 6-7 weeks,
If not 12 to 16 weeks.

 

[TugboatEng]

There are plans views, I don't have them in my possession as they are property of the architect at this moment.

This project starts in 3 weeks. The yard has the fabricators, the materials are not scarce, and I have a vendor for the bellows expansion joint. I'm just looking to optimize the design.

 

[catserveng]

Tug,

A BTW, make sure they have pressure measuring taps at the right locations to evaluate the actual pressures under load, especially since you have an SCR.

I attached the most recent CAT A&I for Exhaust Systems, thought you might already have it but in case you don't it's a good reference even if your engines aren't yellow.

Good luck in your project.

MikeL.