How can i give Hydrogen Gas injection?
 

Hi ,
I am making a simulation of hydrogen gas diffusion in room when it leak from an experiment setup.
So how can i give hydrogen gas injection in room ? bcz injections have only option of hydrogen liquid as injection but i want to inject gas how can i do it?
and i want to give injection from bottom surface to vertical direction how can i give this boundary conditions?
I tried in boundary conditions in velocity components but dnt know some how it don't give solution.!!
What is the problem with it??