Evaporator problem
 

Hi everybody, I've used the heat-exchanger-model in order to simulate heat transfer inside an air â€"cooled evaporator (using R134a refrigerant as auxiliary fluid). However, I'm not sure if I have designed the appropriate geometry (that heat-exchanger-model uses) or chosen the right boundary conditions. I'm novice in FLUENT usage and the user's manual isn't so helpful at this point. So, I've designed in Gambit a cube and applied a hex/map mesh. Then, I've defined the four faces of the cube as walls, the one face as velocity inlet and the opposite one as outflow….am' I right??? Thanks in advance…