hello all i m working on CFD modeling of close clearance rotor.The gap is 2 mm. should i use MRF? i think gap is too small so currently i m working with moving single domain only. what to do?

Hi,

You have not explained what you are trying to do. How big is the rotor? What type of rotor is it? What is the Re of the impeller?

But at first glance I think a MRF approach would be fine, you will just have to be careful to generate a good mesh to capture the geometry.

Glenn Horrocks

thanks Glenn The geometry is having outer vessel (Length 0.4 m and diameter 0.05m) with a close clarance impeller having a rotor of length 0.35 m (nearly same as that of outer vessel)and three blades mounted on rotor (vane type impeller)having same length as that of rotor.the geomerty is somewhat similar to agitated thin film evaporator.

i want to study the flow pattern in my geometry but due to very low gap (< 2 mm) in outer wall of vessel and inner rotor, i m unable to apply moving refernece frame (MRF). currently i m applying whole domain to rotate with outer vessel wall as counter rotating wall. Is this right? if not can u suggest how to model such close clearance vessel.( note that clearance is not at the bottom its at the outer wall and inner agitator).

waiting for your response, thanks a lot in advance sanjay

Hi,

You can model this with MRF with an interface between the rotor and the housing but meshing is difficult. If you can model it as a fully rotating section with the housing counter-rotating that is much better.

Glenn Horrocks

hello Glenn thank a lot