Hi all,(adsbygoogle = window.adsbygoogle || []).push({});

I have a question regarding the mass flow rate of air through a pipe. On paper, it looks like temperature and pressure effect the mass flow rate but I can't rationalize it in my head.

Here's what I got:

Goal: Calculate the actual mass flow rate of lets say, CH4 through a pipe

Given: 10 SCFH (standard conditions are defined as 60F, 1atm)

MW of CH4 = 16.04lb/lb-mol

T=250F

P=114.7psia

My calculation:

ACFH=10SCFH*(14.7psia/114.7psia)*((250+460)/(60+460))= 1.715ft^3/hr

Molar volume=(RT)/P=0.143ft^3/mol

Mass flow rate = molar volume/ACFM*MW=192.37lbs/hr

However, I am told that the mass flow rate doesn't depend on T and P and the calculation should be as follows:

Mass flow rate = SCFH/397*MW = 0.504lbs/hr

The 397 is the molar volume at STP (60F, 1atm)

Who is right in this case? Does the mass flow rate depend on T and P?

Thank you for your time and comments.

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# Does T and P effect the mass flow rate of air through a pipe?

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