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-   -   DPM: Heating Laws (http://www.cfd-online.com/Forums/fluent/43789-dpm-heating-laws.html)

AndiG February 16, 2007 12:21

DPM: Heating Laws
 
Hello,

Iīve got a problem with DPM. I want to inject solid particles in a continous phase. The solid particles are heated up there and reach a temperature that is above the melting point. In the basic Fluent heating-laws there is only a vaporization-law included. Could anybody give me UDF-Files which consider also the process of melting??

Here the suggested equations:

for T < Tm:

mp.cp.dT/dt = h.A.dT

for T > Tm:

mp.cp.dT/dt = h.A.dT + mp.dL/dt.Hsf

,where L==liquid fraction and Hsf==latent heat of melting

How can I calculate the liquid fraction? (which Formula)?

Or can somebody tell me how to create such laws/udf-files??

(I already read that it works via the DEFINE_DPM_LAW, perhaps somebody could also give me an example-udf-file for defining a dpm-law, i didnīt find an example in the udf-manual for such a case)

Any help will be greately appreciated,

Andi

Allan Walsh February 16, 2007 15:18

Re: DPM: Heating Laws
 
You could write a UDF using the DEFINE_DPM_LAW, if you are familiar with UDFs. The example in the manual will give you the basic idea. But, it may take you awhile (a few weeks) to code up what you want.

Why don't you try this: - treat the particles as inert - in the material property panel for the inert particle, adjust the particle specific heat as a function of temperature with the piecewise function. At the particle melting temperature, use a specific heat that also includes your latent heat of fusion. At higher temperatures, use a third specific heat relationship.



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