Multi species air-CO2
 

Hi,
we are two students and we're studying the greenhouse effect of CO2. We want to simulate the absorption and the convection of CO2 in a vessel open at the top. The CO2 is heated by a lamp positioned over the vessel. The vessel and the lamp are in a large box filled with air. We read some tutorials about multi species, but in the tutorial the second gas is inserted through a nozzle. We want to start with CO2 in the vessel and air in the box, without mass flows.
Is it possible? How can we set up the problem?
Thank you!
Best regards!
Andrea