Help: operating pressure for deflagration
 

Hello, everybody,

I am doing simulation of deflagration in a tunnel (flame propagation of premixed mixture). The mixture is ignited at one closed end of the tunnel. First, the Mach number <0.1, however,the flow velocity increase fast with time, and the Mach number also increase to a number larger then 0.1.

The reaction flow is treated as compressible flow.

The problem is how should I set the operating pressure in FLUENT6.3.26?
It's suggested in Fluent that when Mach number <0.1, operating pressure=mean flow pressure, while when Mach number >0.1, operating pressure=0 or mean flow pressure.

So what can I do.？
By the way, I use the density-based solver, so I can not use the floating operating pressure.

Thanks very much!

Hi

check if you can overide by writing an udf in fluent? It is my guess only.

Sree

hi, Sree

Thank you. but I can not find the udf choice of operating pressure.

hi Fireman

Can you clearly define, what do you mean by operating pressure. Do you want to set the entire domain at a pressrure equal to the experimental pressure? Do you want to devide your domain and setup two different pressure? Just eloborate a bit please.

Sree

hi Sree,

The operating pressure in fluent is used to reduce the roundoff error for low-Mach flow.

I want to setup the operating pressure equal to the mean flow pressure of the whole domain.
Or I need setup the operating pressure=mean flow pressure when Mach No.<0.1, operating pressure=0 when Mach No.>0.1

Now I don't know how to realize either of the two settings described above.

Thank you very much