what does we mean by frozen rotor. which softwares frozen rotor model is better, fluent or cfx

Hi Sam,

Frozen rotor is a method (developed with the need to simplify the full wheel transient problem) of muli-component turbomachinery simulation to a truncated steady simulation.

It probably is a bad term and a better one would be multiple reference frame with fixed relative position between components.

The problem with a turbomachine is that the flow is unsteady. A nice idea is to solve each component in the right frame ie as steady as possible. If the interactions between the two are applied for all time (rather than just for that time step) ie in one position then the whole problem is steady....wrong but greatly simplified.

There are a bunch of choices, how many passages to match and if they are to be stretched for a mismatch....360 on each side always matches. Where to place the interface between rotating and stationary components and what relative position (one or many) that you choose to simulate.

Fluent and CFX have similar approaches but CFX has worked out more in the stretching in the theta direction and the set-up is easier....basically it is a tubo code and Fluent is more general.

Regards,

Bak_Flow