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Old   February 10, 2009, 02:31
Default Electric arc fault
  #1
chandu
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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
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Old   February 10, 2009, 16:18
Default Re: Electric arc fault
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Glenn Horrocks
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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
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Old   February 11, 2009, 04:02
Default Re: Electric arc fault
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chandu
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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
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Old   February 11, 2009, 16:27
Default Re: Electric arc fault
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Glenn Horrocks
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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
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Old   February 12, 2009, 00:26
Default Re: Electric arc fault
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chandu
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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.....
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Old   February 12, 2009, 16:31
Default Re: Electric arc fault
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Glenn Horrocks
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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
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Old   February 13, 2009, 02:10
Default Re: Electric arc fault
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Daniel Kilian
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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 =?
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Old   August 24, 2012, 03:06
Smile Electric arc fault
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sree
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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
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Old   August 24, 2012, 07:44
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Glenn Horrocks
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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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