Learning Forum

[Morizio]

Hi All,

I'm using ANSYS fluent 19.1 to simulate a reactor with around 15 reactions in it. its a system of 15 reactions mechanism and I wrote a UDF for this purpose. the simulation is working well in my PC with out any error. However, as it takes a long time, I decided to run it on a High-Performance Computing (HPC- Compute Canada) system. but the same simulation is not working there and the error from the first iteration is :  

 

********** ISAT_ABORT  **************

 

 routine  = phi2y                                                               

 location =            1                                                        

 

 message  = non-positive species sum   

 

I was wondering if you could help me to find out the problem and how to solve it.

Thanks,

Morizio

[Rob]

Are you running in parallel on your PC?

[Morizio]

Yes, I do it in parallel in my PC. is there any suggestion to solve this problem? 

 

here is the console report:

......

parallel,

 

Note: 3d, double precision, pressure-based,  species, realizable k-epsilon case read into

      3d, pressure-based,  species, realizable k-epsilon solver.

 

 

 

Done.

 

Reading ""| gunzip -c \"IRRFLOWUNS5.dat.gz\"""...

 

 

 

Parallel variables...

Done.

 

> 

adapt/                  file/                   server/

adjoint/                mesh/                   solve/

define/                 parallel/               surface/

display/                plot/                   views/

exit                    report/

 

> ; Run the solver for this many steps:

/solve/iterate 20

plot-residuals: no graphics functions available.

 

  iter         oh-         o2-          o-         o3-          h2         ho2        ho2-         ho3          oh           h          h+           e          o2   c15h12n2o  c15h13n2o2  c15h14n2o3           p        h2o2     time/iter

!27008 solution is converged

 27008  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0.0000e+00  0:00:00   20

 

********** ISAT_ABORT  **************

 

 routine  = phi2y                                                               

 location =            1                                                        

 message  = non-positive species sum                                            

 

****** END ISAT_ABORT  **************

 

 

********** ISAT_ABORT  **************

 

 routine  = phi2y                                                               

 location =            1                                                        

 message  = non-positive species sum                                            

 

****** END ISAT_ABORT  **************

 

 

********** ISAT_ABORT  **************

 

 routine  = phi2y 

..............

 

 

Many thanks

[Rob]

As it runs in parallel on your PC, but not on the cluster then it's looking like something is missing on the cluster. Have you re-compiled the UDF for the cluster and checked it's hooked correctly? 

[Morizio]

I have compiled it on the HPC system and it is compiled well (based on the report file). but I'm not if it is hooked correctly or not...

the journal file that I have used is:

define/user-defined/compiled-functions compile libudf yes Reactions.c ,,

define/user-defined/compiled-functions load libudf

/file/read-case-data  IRRFLOWUNS5.cas.gz

/solve/iterate 20

/file/write-case-data  IRRFLOWUNSR5.cas.gz

exit

---

should I add any other line for its hooking?

 

Thanks,

Morizio

[Rob]

Make sure any command strings start with /  so always use /define for example.  It may not effect your problem but is good coding practice.