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-   -   Electric arc fault (http://www.cfd-online.com/Forums/cfx/27009-electric-arc-fault.html)

chandu February 10, 2009 03:31

Electric arc fault
 
Hi

I want predict the behavior of electric arc fault, as fault occurs in closed chamber the High temperature and high Pressure rise is take place, how I start this problem to predict the P and T, as I am having input as energy of arc varies with time, So I have to include magnetic and electric field data to create shock wave nature? Please give me subjections so that I can predict the feature of arc

Thank you

regards chandrakanth.G

Glenn Horrocks February 10, 2009 17:18

Re: Electric arc fault
 
Hi,

The simplest approach is to model the arc as a heat source. If that does not capture enough physics for sufficient accuracy then you need to look at a coupled electrical/fluids model and that is far more complicated. This will involve some plasma physics and other stuff which will be very complicated to get working.

I would just start with the heat source approach.

Glenn Horrocks

chandu February 11, 2009 05:02

Re: Electric arc fault
 
Thanks Glenn

I have tried this problem with giving input boundary condition as Heat source,in transient conditions,with this Pressure is constant(not so much rise), i think the heat that i am giving in the medium cuase stady state,no shock waves are created.

Please give me information about plasma physics to solve

Thanks once again

Chandu

Glenn Horrocks February 11, 2009 17:27

Re: Electric arc fault
 
Hi,

I don't understand your last post.

If the heat source did not generate enough heat then don't you just need to increase the heat source power input? Do you know how much power the spark is putting into the air anyway?

Forget about plasma physics. Until you show that the heat source approach is not capturing important physics you should stick with the simpler approach.

Glenn Horrocks

chandu February 12, 2009 01:26

Re: Electric arc fault
 
Hi in my problem iam having the Heat input of arc energy with respect to time,so how can i use this condition in the CFX to generate Shock wave in the air medium.

i approch this problem by taking only air as medium and i given inlet boundary condition as a Heat source(but iam giving maximum Heat energy,not with respect to time varies) to the air from one location remaing i considered as adiabatic wall this i done in transient state,

with this approch pressure is not so much changed as i required(Shock wave not created), How can i approch? is i have to add any speciel equation for heat source with respect to time?if the total arc generation time is 0.1 sec then maximum heat from arc is getting at 0.007 Sec How can i use this condition?

Please give me some advice.....Thanks you.....

Glenn Horrocks February 12, 2009 17:31

Re: Electric arc fault
 
Hi,

Are you running a fully compressible simulation? Have you got a fine grid next to the spark region? Are you using high res spatial differencing and second order time differencing?

Glenn Horrocks

Daniel Kilian February 13, 2009 03:10

Re: Electric arc fault
 
Greetings, i am also in some electric arc simulation. I am using also the first guess approach to model it as an heat source. any other ideas =?

srinivasa August 24, 2012 03:06

Electric arc fault
 
Hi Everyone,

I am looking for the same electric arc simulation in CFD / Fluent to show effect of this arc fault how pressure can rise. did any one know how to proceed .. Pls help me to proceed further.

Regards
GCK

ghorrocks August 24, 2012 07:44

This thread has plenty of suggestions - start off with the arc as a heat source and see how it heats things from there.


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