I have a question about gas valve selection and working out the CV. The equation I have needs the mass flow in kg/hr, but I have been given the volumetric flow rate in litres/minute. How do I go about converting this? Thanks


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You can probably assume the natural gas is an ideal gas, then apply the corresponding equation of state on any arbitrary control volume of the flow:

$$ pV=mRT $$

where $p$ is pressure, $V$ is volume, $m$ is mass, $R$ is the specific gas constant, and $T$ is temperature. $R$ for methane is $518.3 \frac{J}{kg \cdot K}$, which might be close enough. You will also need to know pressure and temperature, then just solve the equation of state for mass. Don't forget to convert your units of time as well.


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