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-   -   DPM Modelling: Colloid droplet evaporation (http://www.cfd-online.com/Forums/fluent/45573-dpm-modelling-colloid-droplet-evaporation.html)

Meng Wai Woo August 1, 2007 00:23

DPM Modelling: Colloid droplet evaporation
 
Hi- This is a long message to make my case clear. If anyone is able, please help.

Case: -Running a DPM model to tracking evaporating droplets.

-Specific to my desired product, the evpaoration rate should drop corrsponding to the droplet moisture content.

-Implemented a UDF droplet drying model which returns the droplet saturated surface vapour pressure correponding to the droplet mositure for 80% volatile droplet.

-Arbitrarily set the boiling point very high to activate only the built-in evaporation model.

Problem: -There is a sudden drop in particle mass throughout the evaporation preiod towards the end of of the evaporation curve wher the volatile component is ~4%. The final volatile component after the drop is 0%.

-Please go to the link attached below for the illustration. this is an enlargement of the final section fo the curve.

-Not sure why is this happening. Try to debug the UDF. It should give a continuous saturation pressure. After the drop, the evaporation model is not activated anymore.

-Is this a FLUENT built-in limitation? Anyone has idea how to overcome this?

http://img297.imageshack.us/img297/3...gcdcrm2.th.jpg

Worried, Woo

Meng Wai Woo August 1, 2007 00:27

Re: DPM Modelling: Colloid droplet evaporation
 
Another picture illustrating my problem. this is the enlargement of the droplet mass vs time curve towards the end of the evaporation period.

http://img232.imageshack.us/img232/5...gcdcfp0.th.jpg


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