[chniranjanreddy]

Hi,

I am trying to model the water flow in a concentric annulus and predict the pressure drop values. For the case without inner cylinder rotation, the pressure drop values are in close agreement with the experimental data reported in the literature. For the case with inner cylinder rotation, I used rotating wall boundary condition in CFX and I am getting the pressure drop values same as in the case of without rotation. It seems there is no effect of inner pipe rotation on the pressure drop predicted by CFX model but there is a strong effect of rotation is observed in experimental data. Can somebody help me in resolving this issue?

I tried to refine the mesh in the near wall and overall mesh also, but this doesn't have any effect on the results.

Pipe dimensions: Inner pipe diameter: 0.0334 m ; Outer pipe diameter: 0.062 m, Pipe length: 10 m. Inlet velocity: 1.78 m/s; Pipe rotation: 0, 120 rpm.

Turbulence model: SST

I have attached the experimental results published in literature.

Thanks and regards
Niranjan

[ghorrocks]

Have you checked the basics? https://www.cfd-online.com/Wiki/Ansy..._inaccurate.3F

Assuming you have checked the basics: If this is a turbulent flow then I would think a default 2-eqn model will not handle the turbulence anisotropy. Try the curvature correction model in the SST model. Even better, try a RSM or LES model.