Hello all can anyone tell me how we put boundary condition for fan blade problem. I am trying using inlet as a static pressure and outlet as a mass flow rate. thanks in advance

A static pressure inlet condition is not a good idea for several reasons. Specifically for fan applications, a given static pressure inlet condition can correspond to multiple volumetric flow rates (depending on the shape of the fan performance curve). So, I would choose a mass flow inlet that is representative of your volumetric flow rate and use a static pressure outlet.

Hi,

the static pressure inlet is not a stable boundary condition because it does not put a "limit constraint" on the momentum equations. As noted by Ron this has the consequence of maybe having more than one solution for the machine caracteristics?

A total pressure boundary condition at the inlet and mass flow outlet is stable or total inlet and static outlet. It all depends on what you want to know if you set one you will get the other.

Hope this helps.

Regards,

Bak_Flow