CFD capabilities
 

Hi there,

I have a client that would like to install a natural gas pipe. The pipe will be made from PE pipe using diameters between 180mm-400mm and will be approximately 20km long. The client would like to have a 3D model of the entire pipe created, and then analyse the model using CFD to work out pressure loss along the length of the pipe.

I have very limited experience using CFD so I wasn't too sure about this, but my first thought was that using CFD for this purpose would be a waste of time due to the fact that it would take a very long time to model the entire 20km pipe, and the pressure loss results that we would obtain would likely not be significantly different than those obtained using simple hand calculations. And would a CFD simulation even work at all for a model of this size, without needing some sort of super-computer? Does anyone have any thoughts on this?

Thanks for your help,

James

Sounds like total overkill, and probably nowhere near as effective as purpose-written pipe network analysis software.

If client insists on the use of CFD, consider modeling a pipe section to pinpoint where the flow profile is fully developed (there are empirical correlations to use as a first estimate) and then some lengths to find a lossfactor per length scale. Really dont see the added value of CFD here either though.

Its you job as the consultant to tell them CFD is not needed in this case, and would be a waste of time. Pipe flow has been well studied and one can make use of compressible flow equations quite easily, This includes K-factors for bends, reducers, roughness of the pipe wall ect. Plus then you can calculatee curves for the pressure drop depending on the temperature, flow rate ect.

Just Reiterating
 

Hi James, I will just say, for sake of further support,

Don't bother with CFD.

It will not tell you anything that you don't already know. Seriously, it's just a pipe, what can happen? Simple, time-tested and well proven results from fluids are much more practical (and reliable). CFD would be too cumbersome to actually even implement all real life factors (surface roughness, junction effects, did the sun even come up on that day?). Definitely no to CFD if all that they are interested in is pressure loss.

Also, given the scope of the problem. I seriously doubt that the customer can even afford ($$) to perform the CFD