It was quite easy to add the thermal aspect in our previous case. Indeed, we have just had to highlight the option "Thermal" and added the thermal initial (for the fluid) and boundary (for the wall) conditions.
First case: Inlet
temperature of the fluid: 20C
Wall temperature:
100C
Here are the temperature profiles in laminar and turbulent conditions:
Laminar case:
Turbulent case:
The outlet temperature of the fluid is, for the laminar
case, 95-100C and for the turbulent case, 30-35C.
Second case: Inlet
temperature of the fluid: 100C
Wall temperature:
20C
Laminar case:
Turbulent case:
The outlet temperature of the fluid is, for the laminar case, 20-25C and for the turbulent case, 75C.
Comments
Summary of the results: Outlet temperature of
the fluid
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In laminar, the outlet temperature of the fluid is
quite equal to the wall temperature whereas in the turbulent case, the
outlet temperature of the fluid does not reach the wall temperature.
From the outlet temperature, it seems that
the heat transfer is higher in the laminar case than in the turbulent one.
Indeed. the time spent by the fluid in the labyrinth is more important
in laminar conditions than in turbulent ones. In fact, by looking at the
velocity profile, we can notice that the fluid even in turbulent, does
not pass through the whole labyrinth. There is a preferencial way. Besides,
the inlet velocity in the turbulent case is 100 times higher than for the
laminar case. So the fluid passing through the labyrinth has not
enough time to be heated or cooled by the wall.
In the other hand, we can notice, from the temperature
profiles, that the heat transfer between walls and the fluid in the "dead
zones" is better in the turbulent case than in the laminar one. The
convective effect of the turbulence plays an important role in the homogeneisation
of the temperature in the labyrinth.
