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Convection + Radiation BC

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Old   December 11, 2003, 17:53
Default Convection + Radiation BC
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dgd
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Could anyone advise how to add both the convective heat loss (linear heat bc) and the radiative heat loss to the same region?
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Old   July 14, 2004, 09:09
Default Re: Convection + Radiation BC
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mike
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Hello, just set two separate patch/covals for the same region as the sources are additive and hence the heat loss will be a net one.

I think these patches will need area multipliers, but you can check by looking at examples from the PHOENICS literature or working out units. Sources to the heat equations are in units Watts.

the heat transfer loss Q is : Q=htc(Tw-Tphi); where Tw=temp of wall or temp outside the domain. and htc is the heat transfer coefficient.

So in Phoenics for the coval Co=htc and Val =Tw

Radiative heat loss will be of the form Qrad= sigma Eps(Tw^4 -T^phi). Where sigma Eps are stefhan boltzman and emmisivity or something like this. In Phoenics there is a special patch to add radiative heat loss. Alternatively you will have to express Qrad in terms of Co(Val-Phi).

There will be plenty of examples of how to do this.

But to summarise two separate patch/covals are ok for the same region the net heat loss will be a combined one.

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Old   April 28, 2005, 11:30
Default Re: Convection + Radiation BC
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AMBER
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WAZ UP
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Old   February 19, 2006, 16:28
Default Re: Convection + Radiation BC
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i dunno??
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u r well confusing me plz someone help me wiv ma science coursework.....am stuc in ahole....*cries really bady* aww well im gonna get a e that will be cos of ma pathtic looser techers...grrrrrrrrrrrrr.....im gonna kill every1 argh!!!.........am going mad....stupid bloody coursework....arrhg!!!
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