[JOE BIN]

hello, foamers~ i am get troubled for 2 months about boundary setting in Scalar transport.
I want to simulate radon concentration diffusion in a laneway. The laneway has an inlet and an outlet, there is a radon source face in the end of the laneway. At present, I measured the radon concentration is 1500Bq/m3 (can translated to Kg/m3), so I want to make the concentration reach 1500Bq/m3 though the face source and to see the concentration distribution under identified airflow velocities.
I have tried many solvers.
Firstly, i used simpleFoam to make Velocity field convergence, and then I used tuburlentScalartransportForm (I added a turbulent effect to the CEqn) to simulate radon concentration diffusion, but the face is not diffused.
Secondly, i thought maybe the solver is not right, then i complied a tubulentSimpleFoam (added a turbulent concentration CEqn), but it still not work.

this problem make me frustrated in two months, is anyone can help me ? any advise is much appreciated
i simplified the model and upload the files.

[JOE BIN]

[JOE BIN]