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multiphase VS multicomponet

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Old   July 2, 2002, 02:47
Default multiphase VS multicomponet
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dear all

anybody know what is multiphase same or difference from multicomponet?
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Old   July 2, 2002, 04:49
Default Re: multiphase VS multicomponet
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Bart Prast
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multiphase example: water vapour + liquid water multicomponent example: air(oxygen, nitrogen, carbondioxide, etc)
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Old   July 3, 2002, 00:35
Default Re: multiphase VS multicomponet
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Thank you Bart Prast for you answer and i have some quation ..

If mywork have water(liquid)+air can i use multicomponent (water+O2+N2+CO2)? Or I must use multiphase only.
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Old   July 3, 2002, 01:03
Default Re: multiphase VS multicomponet
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Hwan Shin
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Multi-component flow: The species are mixed at the molecular level. The model equations solve for common velocity and temperature fields, and mass transfer of one species in another is governed by diffusion driven by concentration gradients.

Multi-phase flow: The species are mixed at much larger than molecular length scale. They are given potentially different velocity and temperature fields etc., and these interact via empirically specified inter-phase transfer terms.

from CFX4 user manual
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Old   July 3, 2002, 04:19
Default Re: multiphase VS multicomponet
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Thank you Hwan Shin for your answer.
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Old   July 3, 2002, 09:39
Default Re: multiphase VS multicomponet
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Bouke
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I don't think you can use multicomponent fluids in multiphase simulations in CFX 5.5 (but please correct me if I'm wrong).

In multicomponent fluids the density is a function of composition, temperature and pressure. Hence multicomponent fluids are always compressible and you cannot do compressible multiphase simulations in CFX 5.5.

However, it might be possiible in the upcoming version: "CFX-5.5.1 can now simulate low speed compressible multiphase problems." (from the CFX website).

Whether you need to use a multicomponent fluid is another question, only if there is some significant (for the flow) change in composition in your model. If the composition change does not influence the flow then you might consider using additional scalars instead of components.

good luck,

Bouke
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