How to set up the B.C. for LNG gas
 

I'd like to simulate LNG gas in 3D pipe with the by-pass line.

The geometry is a quite simple - just 2 short pipes (4 m length). those pipelines are connected bypass line (a kind of W shape)

I want to know how much pressure on the elbow part of bypass line

But, I only know the inlet pressure - 60 bar (6Mpa).

How do I set up the inlet BC? also How to define the LNG gas in FLUENT?

Do I need other variables?

Please let me know any ideas for this problem.

Best Regards