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-   -   about DPM UDF fluent5.4.8 (http://www.cfd-online.com/Forums/fluent/31364-about-dpm-udf-fluent5-4-8-a.html)

Devy April 28, 2003 10:28

about DPM UDF fluent5.4.8
 
I have another problem.I used Compiled UDFs.In my DEFINE_DPM_SOURCE,I just use S->mass and S->energy.I activate DEFINE_DPM_LAW and DEFINE_DPM_SWITCH in FLUENT in the Custom Laws panel, which is opened from the Set Injection Properties panel.I also activate DEFINE_DPM_SOURCE in FLUENT in the Discrete Phase Model panel.When I perform trajectory calculations,I can get a result if I select Uncoupled Calculations.But if I select Coupled Calculations,it's divergence detected.

regards

Devy

phd_y2k2001 April 28, 2003 11:35

Re: about DPM UDF fluent5.4.8
 
This is because the effect of the particles in the primary flow is too much, decrease the time steps both for the primary and particulate flow or limit ur number of injection of particles.

How many particles are you injecting/sec ??

# of particles=total mass flow rate of particles/mass of one particle..

devy April 29, 2003 05:15

Re: about DPM UDF fluent5.4.8
 
Hi,

Thank you for your reply.

total mass flow rate of particles is 0.017kg/s. mass flow rate of primary flow is 0.17kg/s.

phd_y2k2001 April 29, 2003 09:36

Re: about DPM UDF fluent5.4.8
 
So you know whats your problem now. If you inject these amount of particles through a narrow inlet, the local concentration becomes higher than 10%. U may want to perform one-way coupling and then 2way ..


Devy May 1, 2003 23:00

Re: about DPM UDF fluent5.4.8
 
Hello,

Than you for your help.

total mass flow rate of particles is 0.017kg/s. mass flow rate of primary flow is 0.17kg/s.

But when I total mass flow rate of particles is 0.00017kg/s, it's divergence detected if I select Coupled Calculations.

What is one-way coupling and then 2way ?

Thank you


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