Convergence of calculation of internal energy(pressure, density) case hydrogen

[ELBAAMRANI]

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Description

I have a problem of Convergence of calculation of internal energy(pressure, density) case hydrogen. I use Refprop under Excel '=@Energy($B$1;"PD";"Molar SI";$B$7;Q14) P = 700 MPa: pressure D = [37 to 15] liquid density kg/m3

Steps to Reproduce

1. [First Step]
2. [Second Step]
3. [and so on...]

Expected behavior: [What you expect to happen]

Actual behavior: [What actually happens]

Versions

REFPROP Version: [REFPROP version 10]
Operating System and Version: [Windows 11 are running REFPROP on]
Access Method: [How you are accessing REFPROP (Excel)

Additional Information

I had the same problem using Refrop 9.1

Many Thanks

[ianhbell]

I am struggling to reproduce your problem. Please give me a single output that is failing, with units. Right now you are mixing density units as far as I can make out

[ELBAAMRANI]

I appreciate your quick response. I whant to calculate liquid density in function of pressure and density for the Hydrogen fluid. I use under Excel this call : @.***($B$1;"PD";"Molar SI";$B$7;Q14) B7 = pressure = 700 MPa Q14 = liquid density = @LiquidDensity($B$1;"Tliq";"Molar SI";Q12;0) For Tliq = Q12 = 23.8225 K ==> Q14 = liquid density = 32.965041 ==> Internal Energy = 32817.702 ==> OK And for Tliq = 24.42 K ==> Q14 = liquid density = 32.515925 ==> Internal Energy NOK [Une image contenant texte, capture d’écran, ligne, Police Description générée automatiquement] And the same problem for Tliq = 24 to critical temperature = 33.145 K

[ianhbell]

Please provide units for all quantities. You'll want to respond in the web client to attach images

[ELBAAMRANI]

OK Pressure : MPa Temperature Tliq : K Liquid density : kg/m3 Internal Energy = KJ/kg Thanks

[ianhbell]

The density units I don't think are kg/m^3. I think they are mol/dm^3, no?

[ELBAAMRANI]

Oups, I'll check But any way, I call the functions assuming that the unit is respected My main input is the temperature (K) and the pressure (MPa) , the rest I suppose use the right units

[ELBAAMRANI]

I can send you the Excel file I use if you want.

[ianhbell]

I see the problem: your input is at too high a temperature for 700 MPa:

import os
import numpy as np 
import ctREFPROP.ctREFPROP as ct
os.environ['RPPREFIX'] = os.getenv('HOME')+'/REFPROP10'

root = os.getenv('RPPREFIX')
RP = ct.REFPROPFunctionLibrary(root)
RP.SETPATHdll(root)
print(f'version: {RP.RPVersion()}')

z = [1]

r1 = RP.REFPROPdll('HYDROGEN','TQ','D',RP.MOLAR_BASE_SI,0,0,23.8225,0,z)
print(r1.Output[0], r1.herr)
r1 = RP.REFPROPdll('HYDROGEN','PD','E',RP.MOLAR_BASE_SI,0,0,700e6,r1.Output[0],z)
print(r1.Output[0], r1.herr)

r1 = RP.REFPROPdll('HYDROGEN','TQ','D',RP.MOLAR_BASE_SI,0,0,24.42,0,z)
print(r1.Output[0], r1.herr)
r1 = RP.REFPROPdll('HYDROGEN','PD','E',RP.MOLAR_BASE_SI,0,0,700e6,r1.Output[0],z)
print(r1.Output[0], r1.herr)

yielding

version: 10.0
32965.04080455675 
32817.70218567939 [PDFLSH warning -1] One or more inputs are out of range; Temperature above upper limit: T = 1468.73 K, Tmax = 1000.00 K.
32533.65518846334 
33688.3616820967 [PDFLSH error 1] One or more inputs are out of range; Temperature above 1.5x(upper limit): T = 1504.52 K, Tmax = 1000.00 K.

The first one yields just a VERY high temperature that is already outside the temperature range, but not quite 1.5Tmax, so that is a warning only. The next one yields a temperature outside 1.5Tmax, which is an error

[ELBAAMRANI]

What I dont inderestand is that all inputs temperatures are between Tmin = 14.5 K and the critical temperature = 33.145 K

[ianhbell]

But not when you go to 700 MPa

[ELBAAMRANI]

Because I want to calculate the maximun internal Energy. That is why I use the maximum of pressure which is less than the pressure limit (2000000 kPa)

[ianhbell]

But you are outside the range of validity of the EOS, so you can't do it

[ELBAAMRANI]

Yes, In this case I try to extrapol But this introduce no consistency in the other calculations

[ianhbell]

I don't think there is anything else I can offer; you are doing something that is not supported in REFPROP

[ELBAAMRANI]

I Tank you for your help.