[fluent_noob]

Hello,


I am trying to model the following scenario:
I have a silicon volume filled with CO2. Also, I have an IR emitter (which contains a heater, that heats up and emit IR radiation). The silicon has IR transmissivity of about 60%. So I would assume 60% IR intensity in the volume. Once the IR is in the volume, I want to model -

1. IR absorption (and subsequent relaxation) by CO2 over time
2. Other parameter such as temperature and pressure change in the volume corresponding to this absorption and relaxation.

For the beginning, I plan to use uncomplicated P1 radiation model. My queries are:

1. Can I simulate just the volume w/ "IR source" at the bottom face of the volume without an actual IR source as in the figure below? I know I can provide temperature for the bottom face, but the case will then deviate from the original scenario and I will have temperature effects in addition to the radiation. Is there any other way to define an IR source for a surface?
2. In real life the gases don't just absorb, but they relax as well (release of that absorbed energy) after a certain relaxation time. In ANSYS, I know that we can model the absorption by the gas. But if we run transient simulation, do we also see the relaxation? Is the relaxation time for the gases defined for the gases in ANSYS?

Fig: A rough model of the scenario explained above


Thanks