I have a problem with flush rate differential equation for the following situation.
A furnace has volume V(oven) [m3]. During thermical treatment a polution comes into the furnace with a volume rate Vg [m3/min].
To keep the polution under certain concentration the furnace is flushed with air at volume rate Vf [m3/min].
The flush rate flows at the same rate out with a certain volume of polution. Assume ideal mixing in the oven between air and polution gas.
At t=0 volume of oven is 100% air.
What is the differential equation which describes equilibrium at t=? when volume of polution flushed out is the same as the volume of incoming polution?
In other words: at what time the concentration of polution is not changed any more by flush air? I need equation that describes concentration or volume as a function of time inside the oven.
Any ideas? Thanks!