hello can anyone help me in analysis of pump using CFD? I dont know how to use the effect of rotation in CFD. which mesh is better tetra or hexa? The software is ANSYS CFX.

Hi,

Hexa Mesh is best and to give rotation give the impeller

domain as rotating.

Dear Remith,

Always hexa mesh is better than the tetra mesh, please go through the tutorial file "Flow in an Axial Rotor/Stator" for defining rotation

Tetrahedron mesh is much more easy to build and for the first approaching, use this type of grid.

i agree with Rogerio,

for your initial calculations you can go ahead with tetra mesh, but finally if you are looking for accuracy go with hexa mesh

Even so for a good accuracy, if you use tetra with a good number of elements, it is not to be wondered at you will find a good result. BUT, it´s good to make a study of the independence of the grid.

if you are looking at drag or seperation then it does not make sense to run a case with tetra cell. even if you have good number of cells in your domain.