Significance of passives
 

What is the difference between passive boundary condition (boundary condition) and passive section(regions and initialisation) ?

Good afternoon!

Transport passives work very similar to any other variable that is being transported. They require a boundary condition and an initial condition to find a unique solution.

For example - think of a dye tracer. If I wanted to trace where the flow from the intake region and boundary of a 4-stroke engine I could "dye" the flow from that region and boundary with an passive (call it INTAKE). I would initialize the intake region with that passive equal to 1 and have the corresponding inflow boundary also have the INTAKE passive set to 1. That way any flow entering the intake region keeps the INTAKE passive and all mass in the INTAKE region initially is "dyed" with the INTAKE passive to start.

Let me know if I can be of further assistance!

Thanks,

- John

then sir why we give NOX or HIROY_soot passives in regions and initialisation part? what is the significance of that?

Good morning!

Unless you expect there to be some inital value of NOX or soot in the region of interest it is not necessary to give NOX or HIROY_soot a non-zero value. If you are mapping from a previous run those passives will be set by the the map file.

I recommend taking a look at the following two example cases in Studio to help with what it appears you are trying to do:

- Tumble_GDI_SAGE
- HSDI_Diesel_engine_with_induction

Thanks!

- John

Thank you so much sir.

You're quite welcome.

Sir can you tell me about the position global coordinate center? For an IC engine, is it important to keep the coordinate center at the center of head of Cylinder?

Good morning -

It is a recommended practice but is not necessary unless you are using some of the built in calculations within CONVERGE. For example - a multi-cylinder simulation will not have all cylinders centered on the global coordinate system.

Thanks,

- John