About Nm^3 and Flow Measurement

[dRic2]

I'm panicking right know, and I wonder if someone can answer these questions:

1) Nm^3 is a unit of measurement for Volume or Moles?

2) I have a flow at T=500K and, let's say, it is Q = 100 Nm^3/h

When I find the value of the flow at T=500K I do $Q_{real} = Q* \frac T {273.15K}$. The new Q is in m^3/h ore Nm^3/h?

 

[Chestermiller]

I'm panicking right know, and I wonder if someone can answer these questions:

1) Nm^3 is a unit of measurement for Volume or Moles?

2) I have a flow at T=500K and, let's say, it is Q = 100 Nm^3/h

When I find the value of the flow at T=500K I do $Q_{real} = Q* \frac T {273.15K}$. The new Q is in m^3/h ore Nm^3/h?

please provide the exact wording of your homework problem

 

[dRic2]

It is not an exercise, sorry. I'm a chemE students and I've been doing every exercise with the flow in mol/h for 2 years. This time our professor keeps giving us this strange unit of measurement and I can't understand what it means. I'm sorry I don't know ho to translate my problem correctly in English.

What I figured out is that 1 Nm^3 = 44.6 mol so 100 Nm^3/h = 44600 mol/h. But this works only at T=273.15K and P=1atm

If the volumetric flow remains constant if the the Temperature changes so does its density and the number of moles.

 

[mjc123]

44.6 moles of ideal gas at STP occupy 1 m³. What the N is doing there I have no idea. Perhaps it is an idealisation of a real gas - the amount of the real gas that would occupy 1 m³ if it was ideal. Or "ideal at 1 atm and 273.15K". In which case it is equivalent to a number of moles (44.6).
Now I think about it, I have done gas adsorption experiments where the amount of gas adsorbed is expressed as "volume at STP (cc/g)", although it is at 77K, and mol/g would be a more relevant unit.
So that's what I think it is. It's an amount (moles) of gas expressed as a volume.

 

[dRic2]

Thanks for the suggestion. I think the only way to know is to go ask him...

 

[baldbrain]

Nm³/h stands for Normal Cubic Metres per hour, i.e. the flow rate at 0°C, 1.01325 bars atmospheric pressure.
There's also a Standard Cubic Metres per hour, Sm³/h (just so you don't get confused in the future again), which is the flow rate at 20°C, 1.01325 bars atmospheric pressure
None of these are the standard units for volume flow rate. Sm³/h is probably only used in the US. It is not part of the SI system though.