Learning Forum

[Zwernjayden]

I need to model Ethanol and Lox combustion in chamber with a converging diverging nozzle attached. Fuel and Ox are atomized by injector at inlets. What would be the best way to do this. Non-premixed combustion? Do I need a flamelet? Should I use traditional inlets or DPM injections? Do I need multiphase and how would I set that up?

[Vijay Narayan]

Hi Jayden,

Below are a few comments to get you started.

a) If Atomization modelling is needed: then VOF-to-DPM modelling would be required.

To keep it simple, we can assume only DPM injection (and capture the DPM particle size corresponding to secondary breakup). Regular DPM alone doesnt require Multiphase module to be activated.

Chapter 21: Modeling Evaporating Liquid Spray (ansys.com)

b) Are you modelling a detailed mechanism or a few steps reaction. This could guide you to choose PDF based or Species Transport model. I think: with species transport - you can model both fuel and oxidizer as DPM and each evaporating to their respective gaseous component. Whereas in PDF based model, you could only model either the oxidizer or fuel as DPM (In general Fuel is modelled as DPM, but if you choose to model oxidizer as DPM, then you would have to flip the specification of fuel and oxidizer in the combustion model setup panel).

Within PDF models, you can also stick with equillibrium option instead of going in the path of flamelets (to start with).

I hope the above response helps.

Regards

[Zwernjayden]

Sorry I forgot to reply in the thread to notify you. Check my reply below

[Zwernjayden]

 

 

Ok thank you. If I am using a plain oriface atomizer , do I still need an traditional inlet boundary condition defined at the same location and diameter using the injector pressure? Or does the atomizer takes its place.