4 replies to this topic

[mosalih90]

Hello all,

We have a 50mm Nitrogen pipeline with pressure of 4.5 barg. How can I determine the volumetric flowrate (or Gas linear velocity) through this pipeline? I do not have P2 therefore cannot determine the pressure drop and thus mass flowrate.

(T=20C, P= atm)

Thanks in advance

[ankur2061]

mosalih90,

 

You don't have the inlet volume flow rate or the mass flow rate to the pipeline. You also have have no initial or inlet velocity figure with you.

 

You haven't mentioned any pipeline length, so I presume you don't have the data.

 

You only have the start pressure (4.5 barg) at the inlet to the pipeline. You mentioned P=atm, is it the pressure at the end of the pipeline or the ambient condition of pressure and temperature where the pipeline is located? You need to clarify this. 

 

Since this is compressible flow, the density of the gas is decreasing along the flow direction with a corresponding increase in volumetric flow and velocity. Mass flow remains constant.

 

Do you honestly think that with all this missing information any calculations can be done? Your answer is awaited.

 

Regards,

Ankur.

[Anshul619]

Basically,

 

 

Q=Vel. x Area

 

Vel. for n2 in the pipe( taken standard) for horizontal line can be 10 m/s.

 

area can be calculated as A=pi()*d^2

 

But this value is based on the max. velocity taken for n2 line.AND IS ESTIMATE...

 

For accurate result, reply to Ankur sir's well asked question.

[latexman]

Mosalih90,

 

Crane Technical Paper 410 can show you how.  US$60 at http://shop.flowoffl...ry=Publications

[Ajay S. Satpute]

mosalih90,

 

You may have to prepare an excel sheet to calculate pressure drop. Use pressure drop calculation equations(http://www.cheresour...p-correlations/) and equivalent length calculations (http://www.cheresour...pes-and-valves/) available in this site. You need to vary mass flow rate to get the desired/expected outlet pressure. For more accurate results, divide your system in say 5 segments and use the same method for each segments in series.

 

Regards.

 

Ajay S. Satpute