I am setting BC with CEL, and my purpose is to allow liquid flows only through partial parts of the boundary with different mass rates. As I try to do it, I write this expression

step((0.02[m]-x)/1[m])*5+step((x-0.03[m])/1[m])*3

from the plot, it does what I want- some fluid flows with mass flow rate 5, some with 3, and some did not flow between the region 0.02~0.03. But it seems that CFX-pre does not allow this action since the message shows that mass flow rate should be defined to a single value.

the only idea in my head is to separate the boundary to more bounaries, but it cost a lot of time if I want to test many different set of parameters.

Wound anyone mind giving me a better idea?

Thx

Did you really tried xGlobal instead of x?

Hi YZ,

The mass flow condition specifies the bulk flow rate [kg/s], not the local mass flux [kg/(m^2 s)]. To specify the mass flux locally, change the boundary condition to a velocity specified condition.

-CycLone