Mass flow problem
 

I can't understand why when i put some BC into my heat exchanger. For example mass inlet and pressure out. And after reports I've got 0.05 kg/s inlet, fluid domain 0.2 kg/s and outlet -0.0499. Why I've got 0.2 kg/s for my interior?What i have to do ? I tried with pressure based and density based solver and nothing. Could you help me ?
Regards !

Ok, another question when I've got complicated geometry with many opens and another. I determine BC mass flow inlet and pressure outlet i would like to see how much mass flow outlet i have. For example I've got one burner with complicated geometry and I deliver 0,1 kg/s air and the outlet I've got 0,05 kg/s (experimental report). I would like to simulate this. Could you explain how can i determine this kind of solver. I've got 0,1 kg/s, 100 Pa air at the inlet and 0,05 kg/s , 14 Pa air at the outlet.