[Beni7kujaku]

Hello, newbie at Fluent here.
I was trying to do a simple simulation of a pipe (axisymmetric, 1mm from the axis, 400mm long) through which went some o2 (oxygen) slowly (mass flow inlet 1e-5 kg/s).
However, when I changed the density of the oxygen from constant to ideal-gas in Materials, then ran the simulation, the density of the fluid jumped from 1.3kg/m3 (what I would expect from oxygen at 1 bar and 300K) to almost 2.6kg/m3.
The plots for temperature and static pressure are almost constant at 300K and 1.00e+05 Pa, but the absolute pressure is 2e5Pa. I suppose the density difference is because the operating pressure is set to 1 bar, but I can't see where I can change that.

Can you help me?

[LiuYD]

Originally Posted by Beni7kujaku

Hello, newbie at Fluent here.
I was trying to do a simple simulation of a pipe (axisymmetric, 1mm from the axis, 400mm long) through which went some o2 (oxygen) slowly (mass flow inlet 1e-5 kg/s).
However, when I changed the density of the oxygen from constant to ideal-gas in Materials, then ran the simulation, the density of the fluid jumped from 1.3kg/m3 (what I would expect from oxygen at 1 bar and 300K) to almost 2.6kg/m3.
The plots for temperature and static pressure are almost constant at 300K and 1.00e+05 Pa, but the absolute pressure is 2e5Pa. I suppose the density difference is because the operating pressure is set to 1 bar, but I can't see where I can change that.

Can you help me?

Hi Beni7kujaku
I don't use Fluent very often either, but I remember adjusting the operating pressure. It can indeed affect the density of the gas. The specific place for the modification should be at the boundary condition interface. You can refer to the picture I provided.