[sunyilsh]

Hi everybody

Can anybody help me regarding urea spraying in SCR(selective catalyst reduction) . I used DPM model to simulate urea solution spraying, breaking up of droplets, evaporation, and chemical reaction with exaust gas(continuous phase). However I am faced with questions as follows:
1. The specific meaning of "break up parcels" and so on.
2. The method of defining urea solution as one of material showed in injection panel. If use UDF, how to use it?
3. The custom laws of droplet particle doesn't have chemical reactions. How and where to add chemical reaction with exaust gas?
4. Do I need to use the nozzle model provided by fluent itself or set a model defined by myself?

Thanks

[shk12345]

Originally Posted by sunyilsh

Hi everybody

Can anybody help me regarding urea spraying in SCR(selective catalyst reduction) . I used DPM model to simulate urea solution spraying, breaking up of droplets, evaporation, and chemical reaction with exaust gas(continuous phase). However I am faced with questions as follows:
1. The specific meaning of "break up parcels" and so on.
2. The method of defining urea solution as one of material showed in injection panel. If use UDF, how to use it?
3. The custom laws of droplet particle doesn't have chemical reactions. How and where to add chemical reaction with exaust gas?
4. Do I need to use the nozzle model provided by fluent itself or set a model defined by myself?

Thanks

I am working on DPM since a long time.
I hope i may answer some of your queries.
1) Breakup means how many parcels are been breake up based on the instabilities that re in the flow. You may change the parameters of the breakup models primary or secondary and fine tune the amount of the particles being break up.
2)Just use the default material panel and provide the properties of urea there. Then use that urea in the DPM model.
3) I have no idea about it but i think there should be option of reactions in DPM.
4)Use the default models in fluent. Just fine tine them depending upon your injector.

Regards
shk

[sunyilsh]

Originally Posted by shk12345

I am working on DPM since a long time.
I hope i may answer some of your queries.
1) Breakup means how many parcels are been breake up based on the instabilities that re in the flow. You may change the parameters of the breakup models primary or secondary and fine tune the amount of the particles being break up.
2)Just use the default material panel and provide the properties of urea there. Then use that urea in the DPM model.
3) I have no idea about it but i think there should be option of reactions in DPM.
4)Use the default models in fluent. Just fine tine them depending upon your injector.

Regards
shk

Thank you for your answers. Does the material of DPM droplets evapourate and then become one of the species of the continuous phase? If so, can I use the "species transport" model to finish the edit chemical reactions ?
I am also doubt about the your answer about "particle parcel". How can I edit the amout droplet contained in one parcel ?

Regards