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 Roland August 2, 2006 08:56

CFX-Pre Expression

Hello, who can help me?

I want to create an expression as a function of time

At t=0s I want a Temperature of 300K then until t=60s T shoulp be equal to 923.4 K then after t>60s T should be stable at the level of 923.4 K. So how can I get an expression with this time Steps? For 0s=<t=<60s I would need an expression like: T=300[K]+Time*10.39[K s^-1]

And for t>60s I would need the expression T=923,4K

But how can I combine this?

 opaque August 2, 2006 09:16

Re: CFX-Pre Expression

Dear Roland,

Please read the documentation about the CEL step function.. It is meant for this type of situation..

Opaque..

 Ram Dayal August 2, 2006 10:18

Re: CFX-Pre Expression

Dear Roland Use min function. first calculate T1=300[K]+Time*10.39[K s^-1],then T2=923.4[K] then T=min(T1,T2). I think this should work. Bye Ram Dayal

 Roland August 2, 2006 10:29

Re: CFX-Pre Expression

Thank you, it worked with the step function

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