4 replies to this topic

[tarekmonier]

Is it laminar flow or turbulent flow inside the cyclone separator(solid-gas)?

[Art Montemayor]

Tarek:

The way to find out if a fluid is in turbulent or laminar flow is to find out its Reynolds Number. If you are going to discuss the type of a fluid flow, you had better be very knowledgeable about Mr. Reynolds and his Number.

You should know the region where the Reynolds Number is less than 2100 and that region where it is over 4,000. YOU are the only one who can calculate the Reynolds Number for your cyclone separator --- since you have failed to give us all of your Basic Data. We don't even know the diameter. Apply the Reynolds Number and you have your answer.

[tarekmonier]

Thank you Art Montemayor

[Andree]

in all I was dealing with, including hydrocyclones, the flow was turbulet... moreover, the turbulence is very anisotropic inside the cyclone body (within the vortex)... I was modelling cyclonic dust separators using CFD and k-epsilon RNG, RSM or LES models (these are most recommended for cyclones).

[Andree]

Re 2000, 3500 (or 4000) are the limiting value between laminar, intermediate and turbulent flows but for flow in pipe... for mixing these values are different, for flow around the rigid body different, and the Re are defined in different way (different characteristic length)... for cyclone many authors use Reynolds number based on inlet velocity and cyclone body diameter, but I doubt if the same criteria apply for such definition of Re