get rid of negtive mesh
 

The geometry is not so complicated.
I spent two days to get rid of the negative values. but still no success.
could anybody help me?

I feel it is the problem of association.

Would you like to describe your geometry? Why there is outer region?

if it's not association. then the problem comes from law bunching in the edges. one edge has different bunching than the one parallel to her. may be you forgot to apply "copy to parallel edge"...

I had the association problem before.
Right now, I believe the association is fine.
The whole domain is basically a "T" with two converging nozzle facing each other inside the "T".
I attached tin file.