How to Calculate Nitrogen Purge Velocity in Fixed Volume Tanks?

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SUMMARY

The discussion focuses on calculating the nitrogen purge velocity in fixed volume tanks, specifically addressing a scenario involving four tanks with a volume of 90m³ each, initially at 701.3 kPag and purged to 131.3 kPag through a 100mm pipe. Key factors influencing the velocity include not only the pressure and density of the nitrogen gas but also the pipe's length, roughness, and entry geometry. The conversation emphasizes the importance of considering both major and minor head losses in compressible fluids, as well as the impact of temperature changes on flow measurements.

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bluesman4509
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This is not homework, but a problem from work.

If 4 tanks with fixed 90m^3 volume contained Nitrogen gas at 701.3 kPag were purged to 131.3 kPag through a 100mm pipe how would I work out the velocity/volumetric flow rate of the output?

Thanks
 
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The velocity isn't dependent only upon the fluid (pressure, viscosity, density), and not just on the diameter of the 100mm pipe, either, but also the length of the tube, it's roughness, and the entry geometry (exit, not so much provided its flush or free air). Is the tube's entrance flush with the interior of the tank, or in free air?
 
Thanks all for the pointers,

mugsliens I've completed a subject in fluid mechanics that only looked at incompressible fluids so would I be correct in saying that major (friction) and minor (inlet/outlet exspansions) head losses relate smilarly in compressible fluids?

I will receive data from some flow meters soon, since I read in another post that I would need to consider the change in temp. through the pipe I guess introducing measured data would make the theoretical calc useless anyways.
 

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