Learning Forum

[fatemeh.hosseini1992]

Hello everyone,

I am currently simulating a jet milling process. The system consists of a cylindrical chamber with six nozzles. Air enters through the nozzles at a velocity of 200 m/s, creating a strong circulating flow inside the chamber due to the cylindrical geometry. The gas then exits from the bottom outlet of the chamber. I am using the k-ε turbulence model (at this stage I have not added particles yet; I am only simulating the gas phase).

My current setup is as follows:

• Gravity: Off

• Gas model: Ideal gas law

• Inlet boundary condition: Velocity inlet (200 m/s at the nozzles)

• Outlet boundary condition: Pressure outlet

The problem I am facing is that a region of negative static pressure appears inside the chamber, particularly near the outlet

A similar geometry has been attached for reference; it is not my exact geometry, but it is quite similar.I would really appreciate any suggestions or insights regarding this type of flow behavior in jet mill simulations.

[Rob]

Please post some images, pressure along with tangential velocity & axial velocity across the centre yz plane. I suspect I know what's happening but am supposed to use your images to answer questions on here. 

Which turbulence model are you using, and how are you planning on including the particles?