Learning Forum

[Viktoriya Bondus]

Dear ANSYS Support Team,

I am currently investigating a case where warmer air is introduced into a room at 20°C through a velocity inlet. The air from this room is then transferred to an adjacent room through an opening of the same size as the velocity inlet. To prevent backflow, which distorts the data I am aiming to obtain, I extended the pressure outlet in the second room with a pipe. The fluid properties are defined as piecewise linear.

The study focuses on room ventilation. The temperature of the air at the inlet is 303.15K, and the inlet velocities are very low (0.05 m/s), making it a buoyancy-driven flow. The yz-walls are set as brick with shell conduction, with a temperature of 291.65K. This setup ensures that heat is transferred to the outside, resulting in an outlet temperature of 293.15K. The velocity inlet and pressure outlet are vertically aligned, raising the question of whether it is appropriate to set the gauge pressure to 0 Pa or if it needs to be defined differently based on height.

My questions are as follows:

Is it correct to use the average density of the rooms as the operating density, or should it be defined at the pressure outlet?
How does selecting "Use Inlet Density" affect the simulation, and in which scenarios is this option recommended?
Given the vertical alignment of the velocity inlet and pressure outlet, is it possible to set the gauge pressure to 0 Pa, or should it be defined differently based on height?
Thank you for your assistance!

[Essence]

Hello,

In operating conditions, please use outlet density as operating density. Since, this is used to eliminate the hydrostatic pressure effects of air. Yes, you can set outlet pressure to 0 Pa, provided the operating density is applied correctly and is non-zero. It is generally recommended to use outlet density in operating conditions to remove hydrostatic effects.