Hello everyone. I have natural gas (methane) flowing through some piping, and the last little part of pipe is where I'm concerned. The gas goes through a drawn aluminum tube, about 5.08 mm ID (it's a very small tube). The tube has three 90 degree bends where it ejects out of an orifice. It is about 0.2286 m length total. The pressure right before the tubing measures 7"wc.... but I really want to know if there's a pressure drop across this bendy little piece of tube. Problem is I can not put a gauge at the end of the tube, before the orifice. There's reason to believe (from other data) that there may be as big as 1"wc pressure drop across this tube, but I'd like to prove that with technical calcs, and at least get a reasonable close number. Some of the values needed for this were hard to find, but I'll give you what I have d = 0.00508 m pipe roughness = 0.0000015 m L = 0.2286 m density = 0.667 kg/m^3 dynamic viscosity = 0.0000103 Pa*s The problem comes with the velocity of the gas... not sure how to find it. We have a flow meter, which is actually what we are testing to see if it's reading correctly, which will currently read between 12.79-12.98 SLPM, which gives about 10.25 - 10.39 m/s I'm stuck because even if we assume those velocities are correct and proceed to the equations, we still have an unknown friction factor and pressure drop.... PLUS, I'm not sure how exactly to take into account the 90 degree bends... I tried looking up equivilant lengths, but they don't account for pipes that are as small as mine. Any insight would be great/ Thank you EDIT: I had the meter readings wrong, I've updated it.