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IDProjectCategoryView StatusLast Update
0000589ascendfpropspublic2016-03-31 17:37
Assigned Tojohn 
Status assignedResolutionopen 
PlatformLinuxOSUbuntuOS Version12.04 LTS
Product VersionSVN 
Target Version0.9.9Fixed in Version 
Summary0000589: thermal conductivity code incomplete (thcond)
DescriptionThermal conductivity code has been partially implemented eg for nitrogen, but is not yet functioning correctly. Debugging and fixing required.
Steps To Reproducein 'fprops',

./ nitrogen

Output includes:

Testing thermal conductivity values from REFPROP 8.0
k(T=100.000000, rho=0.000000) = -nan (target: 9.277500e-03)
k(T=300.000000, rho=0.000000) = -nan (target: 2.593600e-02)
k(T=100.000000, rho=25.000000) = 1.036408e-01 (target: 1.030900e-02)
k(T=200.000000, rho=10.000000) = 3.508972e-02 (target: 1.854500e-02)
k(T=300.000000, rho=5.000000) = 3.276973e-02 (target: 2.608500e-02)
k(T=126.195000, rho=11.180000) = 3.204393e-02 (target: 1.213200e-02)

(Note that the values don't agree, and there are 'nan' values in two cases also.)
TagsNo tags attached.




2016-03-26 05:55

reporter   ~0001003

the main problem with the thermal conductivity code for nitrogen was that the critical part of it....which inturn had a problem with the dp/drho at constant temperature...i have corrected the error related to gaussian term and power term...but due to lack of critical data for nitrogen i'm not able to do anything further...can u suggest where should i get the data from??


2016-03-27 13:32


helmholtz.c (40,615 bytes)


2016-03-27 13:33

reporter   ~0001004

i have corrected the error in dp/drho at constant T....and uploaded the file helmholtz.c


2016-03-27 13:34

reporter   ~0001005

i checked for the values from the given reference( Viscosity and Thermal Conductivity Equations for Nitrogen, Oxygen, Argon, and Air Int J Thermophys 25. doi:10.1023/B:IJOT.0000022327.04529.f3) on the FPROPS page of thermal conductivity...the values with rho other than 0 are all different...


2016-03-29 14:50

administrator   ~0001006

Thanks, Saurav. I checked your changes; as far as I can tell, you made a chance that cancels out any terms where the pow(delta, gt->d - 2) is infinite. What is the justification for that? To me, it seems that you are fixing a symptom, not a root cause. But perhaps you can explain it?


2016-03-29 15:15


thcond.c (11,762 bytes)


2016-03-29 15:20


result.jpg (213,541 bytes)
result.jpg (213,541 bytes)


2016-03-31 17:13

reporter   ~0001010

actually sir when ever the function ipow got a negative power it just inverted the number and then raised it to that power...if rho was 0,then on inverting it which gave infinity...but raising 0 to any finite power should yield that is why i had to add this statement...


2016-03-31 17:17

reporter   ~0001011

also sir i have fixed the error in answers are correct...major changes i made were correct the thcond_nitrogen->data->k1->rho_star to NITROGEN_RHOC...because throughout our program we used rho in kg m^-3...then in thcond_lamc...brackterm needs to be divided by 10^6 for compensating the mega in dpdrho used in chitilde function...i also rounded off the result at the end in i am uploading the file nitrogen.c,helmholtz.c & thcond.c...and also a screenshot of the result


2016-03-31 17:31


nitrogen.c (19,738 bytes)


2016-03-31 17:35


frpops_files.7z (17,499 bytes)


2016-03-31 17:37


res.jpg (350,589 bytes)

Issue History

Date Modified Username Field Change
2016-03-07 10:39 john New Issue
2016-03-07 10:39 john Status new => assigned
2016-03-07 10:39 john Assigned To => john
2016-03-26 05:55 sauravkumar2014 Note Added: 0001003
2016-03-27 13:32 sauravkumar2014 File Added: helmholtz.c
2016-03-27 13:33 sauravkumar2014 Note Added: 0001004
2016-03-27 13:34 sauravkumar2014 Note Added: 0001005
2016-03-29 14:50 john Note Added: 0001006
2016-03-29 15:15 sauravkumar2014 File Added: thcond.c
2016-03-29 15:20 sauravkumar2014 File Added: result.jpg
2016-03-31 17:13 sauravkumar2014 Note Added: 0001010
2016-03-31 17:17 sauravkumar2014 Note Added: 0001011
2016-03-31 17:31 sauravkumar2014 File Added: nitrogen.c
2016-03-31 17:35 sauravkumar2014 File Added: frpops_files.7z
2016-03-31 17:37 sauravkumar2014 File Added: res.jpg