[wadoud31]

HI all,
I try this simulation to know the mass flow rate of air at the bottom in the furnace, I used the knonw boundary conditions wich are:
1 the speed, mass flow rate and the pressure at the inlet of the ejector.
2 at the bottom of the furmace (atmospheric openning), we have only the atmospheric pressur, normaly is the inlet of atmospheric air.
3 at th top (duct) of furnace is the same (atmospheric openning), normaly is the exit (out).
at the and of this simulation we must confirm the mass flow rate at the bottom;
I am trying to simulate an existing device(ejector) used to purge an fired furnace, but the issue is how we must define the boundary conditions.
I tried the boundary conditions below:
Reference pressure: 1 atm
Inlet of ejector: static pressure 7 bar and velocity 48 m/s
In the bottom of the furnace I tried 2 options:
1 inlet of furnace with a static pressure 0 atm
2 as opening with a static pressure 0atm
Out of the furnace I tried 2 options:
1 outlet of furnace with a static pressure 0 atm
2 as opening with a static pressure 0atm
The simulation did not converge.
NB: the geometry and the conditions is like the site (real case).
I need your help and your advice; thank you in advance.
after trying a lot of different setups, it seems that I need some help with the boundary conditions of my problem. I'm looking for a stable (steady state?) solution
I am using ANSYS CFX 14.5.
thanks, I am very grateful