|
[Sponsors] |
How to calculate Enthalpy in j/mol.kg in ansys ? |
![]() |
|
LinkBack | Thread Tools | Search this Thread | Display Modes |
![]() |
![]() |
#1 |
New Member
Join Date: Nov 2018
Posts: 5
Rep Power: 7 ![]() |
Hi
I have some confusion about how ansys calculates enthalpy in j/mol.kg I have seen many answers that says just multiply enthalpy of a material by the its molecular weight but that simply does not make sense for me because : enthalpy is in j/kg and molecular weight is in kg/mol so the resultant dimension would be j/mol not j/mol.kg as required by ansys? may be this naive question ![]() ![]() Thanks |
|
![]() |
![]() |
![]() |
![]() |
#2 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,728
Rep Power: 66 ![]() ![]() ![]() |
Enthalpy is indeed J/kg or J/mol. I think you are confusing J/kgmol as being kg*mol. A kgmol is not kg*mol but a type of mol.
|
|
![]() |
![]() |
![]() |
![]() |
#3 |
New Member
Join Date: Nov 2018
Posts: 5
Rep Power: 7 ![]() |
so if for example, the enthalpy is 2000 j/mol, how to convert it to j/kgmol?
|
|
![]() |
![]() |
![]() |
![]() |
#4 |
Senior Member
Lucky
Join Date: Apr 2011
Location: Orlando, FL USA
Posts: 5,728
Rep Power: 66 ![]() ![]() ![]() |
Believe it or not, 2000 J/mol is 2000 000 J/kgmol or 2000 kJ/kgmol
|
|
![]() |
![]() |
![]() |
![]() |
#5 |
New Member
Tamil Nadu
Join Date: Dec 2019
Posts: 11
Rep Power: 6 ![]() |
Hi
Actually standard state of enthalpy of CO2 is -393.5 kJ/mol but in fluent the database value of CO2 is -3.935324e+08 J/kg mol. How this is possible??? whether the unit is correct as mentioned before? |
|
![]() |
![]() |
![]() |
![]() |
#6 |
New Member
Vidushi
Join Date: Sep 2018
Location: Cape Town
Posts: 20
Rep Power: 7 ![]() |
kgmol is not kg*mol. It is like a kilo mol.
So 1kgmol = 1000 mol. |
|
![]() |
![]() |
![]() |
![]() |
#7 | |
New Member
Marco Bernagozzi
Join Date: Jul 2019
Location: Brighton, UK
Posts: 3
Rep Power: 7 ![]() |
Quote:
that is correct. In fact you need to multiply by a factor 1000 to go from kJ to J. Moreover, you need to divide by a factor 1000 to go from mol to kmol (let's remember that the lowercase letter 'k' means 'kilo' which is, I think, ancient Greek for 'a thousand'). Thus, being that at the denominator, you need to multiply everything by 1000. So, 3 digits because of kJ + 3 digits because of kmol + 2 digits for scientific notation and there you go you have your e+08. Hope it helps, Marco |
||
![]() |
![]() |
![]() |
![]() |
#8 |
New Member
Laurens
Join Date: Sep 2018
Location: the Netherlands
Posts: 20
Rep Power: 7 ![]() |
I'm still confused as to why Fluent adds 'kg' to indicate 1e3 instead if just 'k'. Haven't seen this anywhere but here.
|
|
![]() |
![]() |
![]() |
|
|
![]() |
||||
Thread | Thread Starter | Forum | Replies | Last Post |
Enthalpies: Am I confused or is OpenFOAM? (rel. standard vs. enthalpy of formation) | KarenRei | OpenFOAM Running, Solving & CFD | 8 | November 10, 2016 18:18 |
How to combine ANSYS Fluent and Structural analysis? | diwakar | ANSYS | 2 | June 18, 2015 12:07 |
Fluid structure interaction | jnattia | Main CFD Forum | 25 | May 21, 2015 09:16 |
error about fsi in CFX and ANSYS | WANGFIRE | CFX | 1 | April 21, 2015 01:48 |
Enthalpy in a binary gas mixture | ChrisA | FLUENT | 0 | August 26, 2013 19:32 |