How to set boundary condition for non-flowing fluid

Hello,

Would not you mind to give me tips. I need to simulate water cooling of sealed water reservoir with heater inside. I give drawing in attached ppt file. In this dreawing tube is going through a sealed volume  with oil (liquid 1). Water (liquid 2) is flowing through the tube. Inside the volume there is a heat source, which by means of convection heats the oil. Flowing water is cooling the oil.

      I need to calculate temperature of oil for given water flow rate and inlet temperature.

I do not know how to set up boundary conditions for non-flowing oil. When I set flow rate 0 (since oil is not flowing), program asks me to set non-zero value. Also, for the same reason, I do not know how to assign the volume to the oil, to which heat will be transfered from heater.


I would appreciate your help.

Regards,

Yahya.

SolidworksFlow Simulation