Vacuum in the furnace
 

Question about lesson Chapter 30: Coal Combustion, you want to specify a vacuum in the furnace.

In the example, the initial conditions are:
Through Coal Inlet air is supplied 1.015e-3 kg / s
Through Air Inlet air is supplied 1.035e-2 kg / s
At the outlet Outlet average static pressure = 0 Pa

How to set the boundary conditions (on Air Inlet and Outlet) to a pressure drop and air flow corresponded to the original value.

Tried a bunch of options obtained by either an error or a decision not to converge.

P.S. I do not know whether this will affect it at boundary conditions but in a furnace set - Buoyancy (for conv. heat).

Can you explain what you are trying to do? I do not understand your explanation.

OK.
How to create the boundary conditions on the in and out. (see illustration).
The model included treatment-Buoyancy.

http://img834.imageshack.us/img834/1811/76427821.jpg

I would set the In boundary to be a mass flow boundary at 1.035e-2 kg/s and the outlet to be a pressure opening at 0Pa. Use a reference pressure of 1atm-20Pa.

You cannot specify both the pressure and flow rate of an inlet boundary. This would over specify the boundary.