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Thermal Diffusivity of Enthalpy

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Old   August 29, 2006, 11:57
Default Hello, Does anyone know how
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E. David Huckaby
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Hello,

Does anyone know how the thermal diffusivity for enthalpy is derived ?

Both
"src/thermophysicalProperties/specie/transport/sutherland/sutherlandTransportI.H " and
"src/thermophysicalProperties/specie/transport/const/constTransportI.H"
in the function alpha() calculate this as:

alpha = kappa / CpBar

with

CpBar = ( (T - Tstd)*(H(T) - H(Tstd)) + Cp(T) )/(sqr(T-Tstd) + 1 )

I would have thought it would be
alpha = kappa/Cp(T).

thanks
Dave
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Old   November 6, 2010, 08:20
Question Re: thermal diffusivity for enthalpy - what is it and what is Cp bar ????
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Richard Samuel
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I was wondering about this also.

For T = Tstd, Cp bar is undefined, therefore I can't understand what sort of property Cp bar is. Some texts call Cp bar the mean value of Cp but that really doesn't make sense here either.

Anyone ???

Richard
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